For Physicians. By Physicians.™

ObGFirst: Get guideline notifications, fast. First month free!Click here

NIH COVID-19 Treatment Guidelines

NOTE: The FDA has addressed the use of bebtelovimab among nonhospitalized patients in light of an increase in subvariants. Due to resistance, bebtelovimab is not currently authorized for emergency use in any US region. Information and guidelines may change rapidly. Check in with listed reference in ‘Learn More – Primary Sources’ to best keep up to date.


NIH has released guidance on the diagnosis, management and treatment of COVID-19. A Panel was convened to develop recommendations, with the understanding that there is still much that is unknown and the guidelines will be updated as additional data become available

Critical Care Treatment

Infection Control When Caring for Patients with COVID-19

  • Aerosol-generating procedures
    • Use fit-tested respirators (N-95 respirators) or powered air-purifying respirators rather than surgical masks
    • The above masks should be used in addition to other PPE (gloves, gown, and eye protection such as a face shield or safety goggles)
  • Endotracheal intubation
    • Should be done by healthcare professionals “with extensive airway management experience, if possible”
    • Intubation should be done with video laryngoscopy, if possible

Hemodynamic Support

  • First-choice vasopressor: Norepinephrine
  • To assess fluid responsiveness
    • Use dynamic parameters, skin temperature, capillary refilling time, and/or lactate levels vs static parameters
  • Acute resuscitation of adults with COVID-19 and shock
    • Use buffered/balanced crystalloids over unbalanced crystalloids
    • Panel recommends against initial use of albumin
  • Septic shock and steroids
    • IV hydrocortisone 200 mg per day administered either as an infusion or in intermittent doses
    • Duration of hydrocortisone is typically a clinical decision
    • Patients who are receiving corticosteroids for COVID-19 are receiving sufficient replacement therapy such that they do not require additional hydrocortisone

Ventilatory Support for Patients with COVID-19

  • Oxygen saturation (SpO2) target
    • Optimal goal is uncertain
    • A target SpO2 of 92% to 96% “seems logical”
    • Experience suggests that SpO2 <92% or >96% may be harmful
  • Prone position
    • Appropriate candidate for awake prone positioning: Patients who can adjust their own position independently and tolerate lying prone
    • Awake proning should not be used as a substitute for intubation and invasive mechanical ventilation in patients with refractory hypoxemia who otherwise meet the indications for these interventions
    • Pregnancy: Acceptable and can be done in left lateral decubitus or fully prone
  • Refractory hypoxemia in patients who otherwise require intubation and mechanical ventilation
    • Panel recommends against using awake prone positioning as a rescue therapy to avoid intubation 
  • Acute hypoxemic respiratory failure despite conventional oxygen therapy
    • Options for providing enhanced respiratory support include high-flow nasal cannula (HFNC), NIPPV, intubation and invasive mechanical ventilation, or extracorporeal membrane oxygenation (ECMO)
    • Use HFNC oxygen rather than noninvasive positive pressure ventilation (NIPPV)
    • If HFNC is unavailable and there is no indication of intubation: Use a closely monitored trial of NIPPV
  • For patients on supplemental oxygen
    • Monitor closely for worsening of respiratory status
    • If respiratory status worsens, the Panel recommends early intubation by an experienced practitioner in a controlled setting
  • For patients mechanically ventilated with ARDS
    • Use low tidal volume (VT) ventilation (VT 4 to 8 mL/kg of predicted body weight) vs higher tidal volumes (VT >8 mL/kg)
    • If refractory hypoxemia despite optimized ventilation, the Panel recommends prone ventilation for 12 to 16 hours per day over no prone ventilation
    • In the setting of hypoxemia and severe ARDS despite optimized ventilation and other rescue strategies, a trial of inhaled pulmonary vasodilators is recommended as a rescue therapy| Taper if there is no rapid improvement in oxygenation

Inpatient Pharmacologic Management

Note: For patients who are hospitalized for reasons other than COVID-19 and who are found to have mild to moderate COVID-19 and a high risk of disease progression, the Panel recommends following its recommendations for treating nonhospitalized patients with COVID-19 (section below)

The following applies to individuals admitted for the treatment of COVID-19

Therapeutic Management of Hospitalized Adults With COVID-19 Based on Disease Severity


  • Recommended for use in hospitalized patients who require supplemental oxygen
    • 200 mg IV once, then RDV 100 mg IV once daily for 4 days or until hospital discharge
    • If the patient progresses to more severe illness, complete course


  • Found to improve survival in hospitalized patients who require supplemental oxygen
    • Greatest effect observed in patients who require mechanical ventilation
    • The Panel recommends against using dexamethasone among patients who do not require supplemental oxygen
  • Primary immunomodulator for all patients who require high-flow nasal canula oxygen, noninvasive ventilation, mechanical ventilation, or ECMO
  • Dose
    • 6 mg IV or PO once daily for up to 10 days or until hospital discharge
    • If dexamethasone is not available, an equivalent dose of another corticosteroid may be used


  • Humanized monoclonal antibody against the interleukin-6 receptor (IL-6R)
    • FDA approved to treat inflammatory diseases
  • Dose
    • 8 mg/kg actual body weight (up to 800 mg) administered as a single IV dose
    • In clinical trials, a third of the participants received a second dose of tocilizumab 8 hours after the first dose if no clinical improvement was observed
  • Avoid tocilizumab for the following
    • Significant immunosuppression | Alanine transaminase >5 times the upper limit of normal | High risk for gastrointestinal perforation | Uncontrolled, serious bacterial, fungal, or non-SARS-CoV-2 viral infection | Absolute neutrophil count <500 cells/µL | Platelet count <50,000 cells/µL


  • Oral Janus kinase (JAK) inhibitor that is selective for JAK1 and JAK2
    • FDA approved to treat rheumatoid arthritis
  • Dose
    • Baricitinib dose is dependent on eGFR; duration of therapy is up to 14 days or until hospital discharge
    • eGFR ≥60 mL/min/1.73 m2: Baricitinib 4 mg PO once daily
    • eGFR 30 to <60 mL/min/1.73 m2: Baricitinib 2 mg PO once daily
    • eGFR 15 to <30 mL/min/1.73 m2: Baricitinib 1 mg PO once daily
    • eGFR <15 mL/min/1.73 m2: Baricitinib is not recommended


  • Oral Janus kinase (JAK) inhibitor for the treatment of rheumatoid arthritis
  • Dose
    • 10 mg PO twice daily for up to 14 days or until hospital discharge
    • Use as an alternative immunomodulatory drug if baricitinib is not available or not feasible to use (BIIa)
    • eGFR <60 mL/min/1.73 m2: Tofacitinib 5 mg PO twice daily


  • Humanized monoclonal antibody against the interleukin-6 receptor (IL-6R)
    • FDA approved to treat rheumatoid arthritis
  • Dose
    • Use the single-dose, prefilled syringe (not the prefilled pen) for SQ injection
    • Reconstitute sarilumab 400 mg in 100 cc 0.9% NaCl and administer as an IV infusion over 1 hour
    • Use as an alternative immunomodulatory drug if tocilizumab is not available or not feasible to use

Therapeutic Management of Nonhospitalized Adults With COVID-19

NIH refers to the CDC guidance to determine at increased risk for progression | See ‘Learn More – Primary Care’ for reference

In Order of Preference

  • Paxlovid (for more information, see ‘oral antivirals below’)
    • Orally twice daily for 5 days, initiated as soon as possible and within 5 days of symptom onset in those aged ≥12 years and weighing ≥40 kg
  • Remdesivir
    • 200 mg IV on Day 1, followed by remdesivir 100 mg IV daily on Days 2 and 3, initiated as soon as possible and within 7 days of symptom onset in those aged ≥12 years and weighing ≥40 kg 

Alternative Therapies to be used ONLY if none of the preferred therapies are available, feasible to deliver, or clinically appropriate (listed in alphabetical order)


800 mg orally twice daily for 5 days, initiated as soon as possible and within 5 days of symptom onset in those aged ≥18 years ONLY when none of the above options can be used

Note: BQ.1 and BQ.1.1 subvariants appear to be resistant to bebtelovimab and as of 11/30/2022, bebtelovimab is not currently authorized for emergency use in any US region | The Panel continues to recommend Paxlovid, followed by remdesivir for treatment of mild to moderate COVID-19 in nonhospitalized adults who are at high risk for progression

More on Oral Antivirals

  • Ritonavir-Boosted Nirmatrelvir (Paxlovid)
    • Nirmatrelvir
      • Orally bioavailable protease inhibitor
      • Works by inhibiting viral protease MPRO (protease that plays an essential role in viral replication)
      • Active against all coronaviruses known to infect humans
    • Packaged with ritonavir (as Paxlovid)
      • Ritonavir is a cytochrome P450 (CYP) 3A4 inhibitor and pharmacokinetic boosting agent
      • Boosts nirmatrelvir concentrations to the target therapeutic ranges

Note: Review other medications to assess drug interactions including OTCs and herbal supplements | University of Liverpool has a site with COVID-19 Drug Interactions (included in the NIH Panel guidelines – see “Learn More – Primary Resources’ below)

  • Molnupiravir
    • Oral prodrug of beta-D-N4-hydroxycytidine (NHC)
    • NHC is a ribonucleoside with antiviral activity against RNA viruses
    • NHC uptake by viral RNA-dependent RNA-polymerases results in viral mutations and lethal mutagenesis

Note: Pregnancy and COVID-19 Oral Antivirals

  • Paxlovid
    • SMFM supports the use of Paxlovid in pregnancy as indicated (see ‘Primary Sources – Learn More’ below)
  • Molnupiravir
    • Although FDA concluded that there is a low risk for genotoxicity, due to concern regarding mutagenesis, the FDA EUA recommends against use during pregnancy
    • The NIH Panel states “However, when other therapies are not available, pregnant people with COVID-19 who are at high risk of progressing to severe disease may reasonably choose molnupiravir therapy after being fully informed of the risks, particularly those who are beyond the time of embryogenesis (i.e., >10 weeks’ gestation). The prescribing clinician should document that a discussion of the risks and benefits occurred and that the patient chose this therapy”


Serologic or Antibody Testing for Diagnosis of SARS-CoV-2 Infection

The Panel does not recommend using serologic testing as the sole basis for diagnosing acute SARS-CoV-2 infection 

  • Serologic or antibody tests can detect recent or prior SARS-CoV-2 infection
  • It may take ≥21 days after symptoms for seroconversion to occur (i.e., IgM and/or IgG antibodies to SARS-CoV-2)
  • NAATs and antigen tests for SARS-CoV-2 occasionally yield false negative results
    • Serologic tests have been used in some settings as an additional diagnostic test for patients who are strongly suspected to have SARS-CoV-2 infection
    • Using a serologic test in combination with a NAAT to detect IgG or total antibodies 3 to 4 weeks after symptom onset maximizes the sensitivity and specificity to detect past infection

Concomitant Medications in Patients with COVID-19

Angiotensin-Converting Enzyme (ACE) Inhibitors and Angiotensin Receptor Blockers (ARBs) and Statins (HMG-CoA Reductase Inhibitors)

  • Continue taking these medications as prescribed
  • The Panel recommends against the use of ACE inhibitors or ARBs for the treatment of COVID-19 outside of the setting of a clinical trial

Chronic Corticosteroids

  • For patients on oral corticosteroid therapy used prior to COVID-19 diagnosis for another underlying condition (e.g., rheumatological diseases)
    • Corticosteroids should not be discontinued
    • Supplemental or stress-dose steroids: Determine use on a case-by-case basis
  • Asthma and chronic obstructive pulmonary disease for control of airway inflammation (daily use)
    • Should not be discontinued

Pregnancy Considerations

  • Betamethasone and dexamethasone cross the placenta and are therefore used for fetal benefit to decrease the risk of RDS in the setting or threatened preterm delivery
  • The Panel recommends “using dexamethasone in pregnant women with COVID-19 who are mechanically ventilated or who require supplemental oxygen but who are not mechanically ventilated”

Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)

  • Continue taking NSAIDs for a co-morbid condition as previously directed by physician
  • “The Panel recommends that there be no difference in the use of antipyretic strategies (e.g., with acetaminophen or NSAIDs) between patients with or without COVID-19”

Coagulopathy Considerations

Antithrombotic Therapy for Nonhospitalized Patients without VTE

  • The Panel recommends against the use of anticoagulants and antiplatelet therapy (aspirin or P2Y12 inhibitors) for the prevention of VTE or arterial thrombosis unless the patient has other indications for the therapy or is participating in a clinical trial
  • The Panel recommends against routinely continuing VTE prophylaxis for patients with COVID-19 after hospital discharge, except in a clinical trial 
  • For patients who are at high risk for VTE and low risk for bleeding, there is insufficient evidence to recommend either for or against continuing anticoagulation after hospital discharge unless another indication for VTE prophylaxis exists

General Considerations for Hospitalized Patients

  • The Panel recommends against using anticoagulant or antiplatelet therapy to prevent arterial thrombosis outside of the usual standard of care for patients without COVID-19 
  • In hospitalized patients, low-molecular-weight heparin (LMWH) or unfractionated heparin (UFH) is preferred over oral anticoagulants, because these 2 types of heparin have shorter half-lives and the effect can be reversed quickly, can be administered intravenously or subcutaneously, and have fewer drug-drug interactions 
  • When heparin is used, LMWH is preferred over UFH

Hospitalized, Nonpregnant Adults Who Require Low-Flow Oxygen and Are Not Receiving Intensive Care Unit Level of Care

  • Use therapeutic-dose heparin for patients who have a D-dimer above the upper limit of normal and have no increased bleeding risk
  • LMWH is preferred over unfractionated heparin
  • Contraindications for therapeutic anticoagulation for COVID-19 due to an increased bleeding risk
    • Platelet count <50 x 109/L
    • Hemoglobin <8 g/dL
    • Need for dual antiplatelet therapy
    • Known bleeding within the last 30 days requiring an emergency room visit or hospitalization
    • Known history of a bleeding disorder
    • Inherited or active acquired bleeding disorder
  • If no VTE
    • Continue therapeutic treatment for 14 days or until hospital discharge, whichever comes first
  • The Panel recommends using prophylactic-dose heparin (LMWH or unfractionated heparin) for patients who are not administered therapeutic heparin unless a contraindication exists 


  • There is insufficient evidence for the Panel to recommend either for or against the use of a therapeutic dose of apixaban for VTE prophylaxis or the prevention of COVID-19 progression.
  • The Panel recommends against the use of a therapeutic dose of rivaroxaban for VTE prophylaxis or the prevention of COVID-19 progression
  • There is insufficient evidence for the Panel to recommend either for or against the use of thrombolytic agents for the treatment of COVID-19
  • The Panel recommends against the use of antiplatelet therapy to prevent COVID-19 progression or death in noncritically ill patients 

Hospitalized, Nonpregnant Adults Who Are Receiving ICU Level of Care (Including Patients Who Are Receiving High-Flow Oxygen)

  • Use prophylactic-dose heparin as VTE prophylaxis unless a contraindication exists 
  • The Panel recommends against the following except in a clinical trial
    • Use of intermediate-dose (e.g., enoxaparin 1 mg/kg daily)
    • Therapeutic-dose anticoagulation for VTE prophylaxis
  • For patients who start on therapeutic-dose heparin while on low-flow oxygen due to COVID-19 and then transfer to the ICU
    • Switch from therapeutic to prophylactic-dose heparin unless a VTE is confirmed 
  • There is insufficient evidence for the Panel to recommend either for or against antiplatelet therapy in critically ill patients with COVID-19

Pregnant Adults

  • The Panel recommends that pregnant patients who are receiving anticoagulant or antiplatelet therapies for underlying conditions continue these medications after they receive a diagnosis of COVID-19
  • Use prophylactic-dose anticoagulation for pregnant patients hospitalized for manifestations of COVID-19 unless otherwise contraindicated
  • Because pregnant patients have not been included in most clinical trials evaluating therapeutic anticoagulation in the setting of COVID-19, there is currently insufficient evidence to recommend either for or against therapeutic anticoagulation for pregnant patients with COVID-19 in the absence of a known VTE

Influenza and COVID-19

Vaccine Considerations

  • It is important to ensure that vaccination programs to protect against influenza continue during the pandemic
  • Patients with COVID-19 can receive inactivated influenza vaccine
  • Moderately or Severely Ill with SARS-CoV-2
    • Consider deferring influenza vaccination until the patients have completed the COVID-19 isolation period and are no longer moderately or severely ill
  • Asymptomatic or not moderately or severely ill with SARS-CoV-2
    • Influenza vaccination can be given when infected individual no longer require isolation
    • Vaccinate sooner if they are in a health care setting for other reasons

Note: Influenza vaccine and a COVID-19 vaccine may be administered concurrently at different injection sites

Testing for Influenza

  • Test for both viruses in all hospitalized patients with acute respiratory illness 
  • The Panel recommends influenza testing in addition to SARS-CoV-2 testing in outpatients with acute respiratory illness if
    • Results will change the clinical management strategy for the patient such as initiating antiviral treatment for influenza 
  • Consider testing patients for other pathogens based on their specific clinical circumstances
    • Additional testing is especially important for patients with influenza who have a high risk of acquiring bacterial superinfections

Treatment for Influenza

  • Antiviral treatment of influenza is the same in all patients with or without SARS-CoV-2 coinfection 
  • Hospitalized patients with suspected influenza
    • Start on empiric treatment for influenza with oseltamivir as soon as possible 
    • Do not wait for influenza test results 
    • Stop antiviral treatment for influenza when influenza has been ruled out by nucleic acid detection assay
      • Nonintubated: Negative report for upper respiratory tract specimens
      • Intubated: Negative report for both upper and lower respiratory tract specimens

Learn More – Primary Sources:

NIH: Coronavirus Disease 2019 (COVID-19) Treatment Guidelines

Underlying Medical Conditions Associated with Higher Risk for Severe COVID-19: Information for Healthcare Providers (

NIH: Paxlovid Drug-Drug Interactions | COVID-19 Treatment Guidelines

Liverpool COVID-19 Interactions (

SMFM: FDA Issues EUA for the Treatment of Mild-to-Moderate COVID-19 (Paxlovid)

CHEST: Antithrombotic therapy in arterial thrombosis and thromboembolism in COVID-19

COVID-19 Testing: CDC Guidance on Virus and Antibody Testing

NOTE: Information and guidelines may change rapidly. Check in with listed references in ‘Learn More – Primary Sources’ to best keep up to date.


The CDC has provided guidance on both viral testing for SARS-CoV-2 as well as the role of antibody testing. Testing for the presence of the virus during the pandemic remains the current diagnostic standard. While antibody testing can play a role for public health teams to understand the spread of the disease, currently its use as a diagnostic test for individuals remains limited. A COVID-19 vaccine will not affect the results of SARS-CoV-2 viral tests.

Viral Testing

Specimen Collection

  • Obtain an upper respiratory specimen for initial diagnostic testing
    • A nasopharyngeal (NP) specimen collected by a healthcare professional  or
    • An oropharyngeal (OP) specimen collected by a healthcare professional  or
    • A nasal mid-turbinate swab collected by a healthcare professional or by a supervised onsite self-collection (using a flocked tapered swab)  or
    • An anterior nares (nasal swab) specimen collected by a healthcare professional or by onsite or home self-collection (using a flocked or spun polyester swab)  or
    • Nasopharyngeal wash/aspirate or nasal wash/aspirate (NW) specimen collected by a healthcare professional
  • Lower respiratory tract specimens
    • Collect and test sputum in patients who develop a productive cough | Induction of sputum is not recommended
    • Under certain clinical circumstances (e.g., those receiving invasive mechanical ventilation), a lower respiratory tract aspirate or bronchoalveolar lavage sample should be collected and tested as a lower respiratory tract specimen

How is SARS-CoV-2 RNA Testing Performed?


  • Usually performed using real-time reverse transcription polymerase chain reaction (RT-PCR)
    • Qualitative detection of RNA
  • Multiple tests on the market that can target various genes
    • Envelope (env) | Nucleocapsid (N) | Spike (S) | RNA-dependent RNA polymerase (RdRp) | ORF1
  • A positive test can only determine presence of SARS-CoV-2 RNA and not whether the virus is intact and capable of infecting others


  • Antigen tests can quickly detect fragments of proteins found on or within the virus by testing samples collected from the nasal cavity using swabs
  • The benefit of antigen testing is speed, with results potentially available within minutes
  • However, antigen tests, while very specific for the virus, are not as sensitive as molecular PCR tests
    • Positive antigen results: Highly accurate but higher chance of false negatives | Negative antigen results may still need PCR confirmation prior to treatment decisions or to prevent inadvertent spread of SARS-CoV-2

Note: Prior receipt of a COVID-19 vaccine should not affect the results of SARS-CoV-2 viral tests (NAAT or antigen)

Breath Sample Analysis

  • FDA has issued an emergency use authorization (EUA) for a diagnostic test that detects chemical compounds in breath samples associated with a SARS-CoV-2 infection
  • Test is performed by a qualified, trained operator under the supervision of a health care provider licensed or authorized by state law to prescribe tests
  • Results available in <3 minutes

Diagnostic Testing

Signs or Symptoms of COVID-19

  • Positive test
    • NAAT: Indicates infection regardless of vaccine status
    • Positive antigen test result may need confirmatory testing if the person has a low likelihood of SARS-CoV-2 infection (e.g., no known exposure to a person with COVID-19 within the last 14 days or is fully vaccinated or has had a SARS-CoV-2 infection in the last 3 months)
    • Isolate if positive test: Discontinue isolation 5 days after symptom onset and at least 24 hours after the resolution of any fever (without the use of fever-reducing medications) | Continue to wear mask around others for 5 additional days
      • Some individuals may require extended isolation and precautions (e.g., severely immunocompromised)
      • Testing is not recommended to determine when infection has resolved
      • Loss of taste and smell may persist for weeks or months after recovery and need not delay the end of isolation​
  • Negative test
    • If symptoms are consistent with COVID-19, may be a false negative | Isolation and further discussion with healthcare professional recommended

Testing to determine resolution of infection

  • May be appropriate for severe illness or immunocompromise
  • “For all others, a test-based strategy is no longer recommended except to discontinue isolation or precautions earlier than would occur under the symptom-based strategy”

Screening Testing

No Symptoms and No Close Contact with Someone Known to Have a COVID-19 Infection

  • Asymptomatic or presymptomatic infection contribute to community SARS-CoV-2 transmission
    • May help with re-opening of businesses, communities, and schools
  • Point-of-care tests (e.g., antigen tests) can be particularly helpful due to short turn-around times
  • Quarantine not required while results are pending
  • Examples of screening programs
    • Testing employees in a workplace setting
    • Testing students, faculty, and staff in a school or university setting
    • Testing a person before or after travel

How Early Will a Test Be Positive and How Long Until Negative?

  • In patient with COVID-19 infection who tested positive using a nasopharyngeal swab
    • Earliest detection: Day 1 of symptoms
    • Peak levels highest within week 1 and therefore probability of detection will be highest during that time
    • Viral load declines by week 3 and therefore virus more likely to be undetectable in to week 4
    • Infection severity: More virus may be present in patients with severe disease and therefore it may take longer to obtain a negative test result vs someone with a mild COVID-19 infection

Performance of RT-PCR Viral Tests

  • RT-PCR specificities are close to 100% because they target specific RNA sequences of the SARS-CoV-2 virus
  • False negative results may be due to
    • Inappropriate timing of collection vs symptom onset
    • Poor sampling technique (need to sample at the back of the nose)
  • False positive results may occur due to lab error or contamination
  • However, even with good analytic performance, PPV and NPV are related to prevalence and therefore can differ between geographic regions
    • In a setting with high COVID-19 prevalence, a negative test does not necessarily rule out the possibility that an individual is infected with SARS-CoV-2

Antibody Testing

General CDC Antibody Guidance

  • According to the CDC

Antibody testing does not replace virologic testing and should not be used to establish the presence or absence of acute SARS-CoV-2 infection

Antibody testing is not currently recommended to assess for immunity to SARS-CoV-2 following COVID-19 vaccination, to assess the need for vaccination in an unvaccinated person, or to determine the need to quarantine after a close contact with someone who has COVID-19

Some antibody tests will not detect the antibodies generated by COVID-19 vaccines

Because these vaccines induce antibodies to specific viral protein targets, post-vaccination antibody test results will be negative in persons without history of previous infection, if the test used does not detect antibodies induced by the vaccine

  • In general, antibodies will be detectable 7 to 14 days after illness onset and will be present in most people by 3 weeks
    • Infectiousness likely decreased by that time
    • Evidence suggests some degree of immunity will have developed
  • IgM and IgG can appear together, usually within 1 to 3 weeks
    • IgG antibodies appear to persist for at least several months
    • Some individuals may be infected but will not develop antibodies
  • Neutralizing antibodies can also be identified and are associated with immunity
  • FDA requires companies providing antibody testing to obtain an EUA

What Are the Different Types of Antibody Tests?

  • Antigenic Targets
    • Spike glycoprotein (S): Present on viral surface and facilitates virus entry
    • Nucleocapsid phosphoprotein (N): Immunodominant and interacts with RNA
    • Protein targeting is important to reduce cross-reactivity (cause of false positives which may occur with other coronaviruses like the common cold) and improve specificity
  • Types of Antibody Testing
    • Binding antibody detection that use purified SARS-CoV-2 (not live virus)
      • Point-of-care (POC) tests
      • Laboratory tests that usually require skilled personnel and specialized equipment
    • Neutralizing antibody detection (none currently FDA authorized)
      • Serum or plasma is incubated with live virus followed by infection and incubation of cells
      • Can take up to 5 days to complete the study

When Can Antibody Testing be Helpful?

Antibody testing may be helpful in the following situations

  • Seroconversion: In a patient who did not receive a positive viral test
    • A positive antibody test at least 7 days following acute illness onset but a previous negative antibody test may indicate new onset SARS-CoV-2 infection
  • To support a diagnosis in the presence of a complex clinical situation, such as patients who present with COVID-19 complications (e.g., multisystem inflammatory syndrome and other post-acute sequelae of COVID-19)
    • Note: Due to antibody persistence, a single positive antibody test result may reflect previous SARS-CoV-2 infection and not a recent illness
  • Clinical, occupational health, and public health purposes, such as serologic surveys

Vaccination and Test Interpretation

  • In a person never vaccinated
    • testing positive for antibody against either N, S, or RBD indicates prior natural infection
  • In a vaccinated person
    • Testing positive for antibody against the vaccine antigen target, such as the S protein, and negative for other antigen: Suggests vaccine-induced antibody and not SARS-CoV-2 infection
    • Testing positive for any antibody other than the vaccine-induced antibody, such as the N protein: Indicates resolving or resolved SARS-CoV-2 infection that could have occurred before or after vaccination
  • The CDC states that

SARS-CoV-2 antibodies, particularly IgG antibodies, might persist for months and possibly years

Therefore, when antibody tests are used to support diagnosis of recent COVID-19, a single positive antibody test result could reflect previous SARS-CoV-2 infection or vaccination rather than the most recent illness

Learn More – Primary Sources:

CDC: Interim Guidelines for Collecting, Handling, and Testing Clinical Specimens from Persons for Coronavirus Disease 2019 (COVID-19)

Interim Guidelines for COVID-19 Antibody Testing in Clinical and Public Health Settings

CDC: Overview of Testing for SARS-CoV-2

CDC: Interim Public Health Recommendations for Fully Vaccinated People

Interpreting SARS-CoV-2 Test Results

The Promise and Peril of Antibody Testing for COVID-19

EUA Authorized Serology Test Performance

CDC Updates and Shortens Recommended Isolation and Quarantine Period for General Population

CDC: Quarantine and Isolation

Coronavirus (COVID-19) Update: FDA Authorizes First COVID-19 Diagnostic Test Using Breath Samples

COVID-19: Category Definitions, Symptoms and Those at Increased Risk

NOTE: Information and guidelines may change rapidly. Check in with listed references in ‘Learn More – Primary Sources’ to best keep up to date. This summary has been updated with the latest CDC guidelines on when to end quarantine.


The novel coronavirus, named SARS-CoV-2, is the pathogen underlying the pandemic (a global outbreak of disease). The disease associated with this virus has been officially named COVID-19. Coronaviruses represent a large family of viruses. They can cause human illness, but many are found in animals and, rarely, animal coronaviruses can evolve and infect people as was the case in previous infectious outbreaks such as MERS and SARS.

COVID-19 Categories (NIH Panel)

  • Asymptomatic or pre-symptomatic infection
    • Test positive for SARS-CoV-2 using a virologic test (i.e., a nucleic acid amplification test [NAAT] or an antigen test)
    • No symptoms that are consistent with COVID-19
  • Mild illness
    • Have any of the various signs and symptoms of COVID-19 (e.g., fever, cough, sore throat, malaise, headache, muscle pain, nausea, vomiting, diarrhea, loss of taste and smell)
    • No shortness of breath, dyspnea, or abnormal chest imaging
  • Moderate illness
    • Evidence of lower respiratory disease during clinical assessment or imaging and oxygen saturation (SpO2) ≥94% on room air at sea level
  • Severe illness
    • SpO2 <94% on room air at sea level, a ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2/FiO2) <300 mm Hg, a respiratory rate >30 breaths/min, or lung infiltrates >50%
  • Critical illness
    • Respiratory failure, septic shock, and/or multiple organ dysfunction

Note: SpO2 is a key parameter for defining the illness categories listed above | Pulse oximetry has important limitations (e.g., skin pigmentation, thickness or temperature) | Clinicians who use SpO2 when assessing a patient must be aware of those limitations and conduct the assessment in the context of that patient’s clinical status

Pregnancy: Oxygen supplementation in pregnancy generally used when SpO2 <95% on room air at sea level to accommodate the physiologic needs of mother and fetus


  • Incubation period
    • Time from exposure to development of symptoms: 2 to 14 days
      • Delta variant studies: Mean incubation period of 4.3 days (see ‘Learn More – Primary Sources Below) which was shorter than initial variants (5.0 days)
      • Omicron variant studies: Median incubation period of 3 to 4 days
  • Signs and Symptoms
    • Fever or chills
    • Cough
    • Shortness of breath or difficulty breathing
    • Fatigue
    • Muscle or body aches
    • Headache
    • New loss of taste or smell
    • Sore throat
    • Congestion or runny nose
    • Nausea or vomiting
    • Diarrhea
  • Additional points regarding presentation
    • Older adults: Especially those with comorbidities may have delayed presentation of fever and respiratory symptoms
    • Fatigue, headache, and muscle aches (myalgia) are among the most commonly reported symptoms in people who are not hospitalized
    • Sore throat and nasal congestion or runny nose (rhinorrhea) also may be prominent symptoms
    • GI symptoms may be relatively common
      • Nausea, vomiting or diarrhea may occur prior to fever and lower respiratory tract signs and symptoms
    • Loss of smell (anosmia) or taste (ageusia) has been commonly reported, especially among women and younger or middle-aged patients

Those at Risk Based on Evidence (CDC)

  • Age
    • The CDC states

Age is the strongest risk factor for severe COVID-19 outcomes. Approximately 54.1 million people aged 65 years or older reside in the United States; in 2020 this age group accounted for 81% of U.S. COVID-19 related deaths, and as of September 2021 the mortality rate in this group was more than 80 times the rate of those aged 18-29

Higher Risk: Meta-analysis or systematic review demonstrates good or strong evidence

  • Asthma
  • Cancer
  • Cerebrovascular disease
  • Chronic kidney disease*
  • Chronic lung diseases limited to
    • Interstitial lung disease
    • Pulmonary embolism
    • Pulmonary hypertension
    • Bronchiectasis
    • COPD (chronic obstructive pulmonary disease)
  • Chronic liver diseases limited to
    • Cirrhosis
    • Non-alcoholic fatty liver disease
    • Alcoholic liver disease
    • Autoimmune hepatitis
  • Cystic fibrosis
  • Diabetes mellitus, type 1 and type 2*‡
  • Disabilities‡
    • Attention-Deficit/Hyperactivity Disorder (ADHD)
    • Cerebral Palsy
    • Congenital Malformations (Birth Defects)
    • Down syndrome
    • Limitations with self-care or activities of daily living
    • Learning Disabilities
    • Spinal Cord Injuries
    • See ‘Learn More – Primary Care’ CDC reference that includes extensive list for included disabilities
  • Heart conditions (such as heart failure, coronary artery disease, or cardiomyopathies)
  • HIV (human immunodeficiency virus)
  • Mental health disorders limited to
    • Mood disorders, including depression
    • Schizophrenia spectrum disorders
  • Neurologic conditions limited to dementia‡
  • Obesity (BMI ≥30 kg/m2 or ≥95th percentile in children)*‡
  • Primary Immunodeficiencies
  • Pregnancy and recent pregnancy
  • Physical inactivity
  • Smoking, current and former
  • Solid organ or hematopoietic cell transplantation
  • Tuberculosis
  • Use of corticosteroids or other immunosuppressive medications

Suggestive Higher Risk: Underlying medical condition or risk factor that neither has a published meta-analysis or systematic review nor completed the CDC systematic review process

  • Children with certain underlying conditions
  • Overweight (BMI ≥25 kg/m2, but <30 kg/m2)
  • Sickle cell disease
  • Substance use disorders

Comorbidities with mostly case series, case reports, or, if other study design, the sample size is small 

  • Overweight (BMI ≥25 kg/m2, but <30 kg/m2)
  • Sickle cell disease
  • Substance use disorders
  • Thalassemia

Mixed Evidence: Meta-analysis or systematic review is inconclusive, either because the aggregated data on the association between an underlying condition and severe COVID-19 outcomes are inconsistent in direction or there are insufficient data

  • Alpha 1 antitrypsin deficiency
  • Bronchopulmonary dysplasia
  • Hepatitis B
  • Hepatitis C
  • Hypertension*
  • Thallassemia


* indicates underlying conditions for which there is evidence for pregnant and non-pregnant people

‡ underlying conditions for which there is evidence in pediatric patients

Learn More – Primary Sources:

Underlying Medical Conditions Associated with Higher Risk for Severe COVID-19: Information for Healthcare Providers

Impact of SARS-CoV-2 Delta variant on incubation, transmission settings and vaccine effectiveness: Results from a nationwide case-control study in France (Lancet Regional Health, 2022)

CDC: Clinical Presentation | Clinical Care Considerations

CDC Coronavirus Disease 2019: Overview of Testing for SARS-CoV-2

Clinical Questions about COVID-19: Questions and Answers

WHO: Novel coronavirus Information Page

JAMA: Coronavirus Disease 2019

FDA: Coronavirus Disease 2019

BMJ: Coronavirus Updates

NEJM: 2019 Novel Coronavirus

Annals of Internal Medicine: Content Related to Coronavirus in Annals of Internal Medicine

JAMA: What Is a Pandemic?

The SAFER Study: What is the Risk to Healthcare Workers for COVID-19 During the Pandemic Peak?


  • Houlihan et al. (The Lancet, 2020) evaluate the risk of HCWs contracting and transmitting COVID-19


  • Prospective cohort study (March 26 to April 8, 2020)
    • SARS-CoV-2 Acquisition in Frontline Healthcare Workers—Evaluation to inform Response (SAFER)
  • Setting
    • National Health Service hospital trust in London, UK
  • Participants
    • Patient-facing healthcare workers (HCWs)
  • Study design
    • Nasopharyngeal swabs were collected twice weekly for RT-PCR testing | RT-PCR tests were done twice a week
    • HCWs symptom data were tracked


  • Total of 200 HCWs were enrolled
    • Median age: 34 (IQR 29 to 44) years
    • Evidence of COVID-19 at any time point: 44% (87 of 200 HCWs)
      • 21% had at least 1 positive RT-PCR test
      • Antibodies: 20% seroconverted and 25% were already seropositive at study entry
    • No hospitalizations reported
  • Mean duration of SARS-CoV-2 detection: 12.9 days (95% CI, 9.4 to 17.3)
    • Longest duration: 29 days
  • Trend towards a higher infection rate in younger HCWs <30 years (p=0.0199)
    • <30: 55%
    • >50: 33%
  • Asymptomatic carriage
    • Symptoms within 7 days of positive test: 48%
    • No symptoms within 7 days of positive test: 38%
  • Infection rates
    • Infection rate within 1 month in those with negative RT-PCR test and without antibodies: 13% (14 of 112 HCWs)
    • Infection rate in HCWs in those who had antibodies with negative RT-PCR at enrollment: 3% (1 of 33 HCWs)
    • Most infections occurred during the week with the highest number of new cases in London


  • 44% of HCWs had evidence of SARS-CoV-2 infection through RT-PCR or serology
    • Higher than other international reports
    • Percentage >2x that of the general population in London
  • The authors suggest that urgent policies are needed
    • HCWs need adequate PPE
    • Adequately protect against asymptomatic transmission into the general population from HCWs (through surveillance testing)

Learn More – Primary Sources:

Pandemic peak SARS-CoV-2 infection and seroconversion rates in London frontline health-care workers

Does Hydroxychloroquine Provide Benefit in Nonhospitalized Patients with Early COVID-19 Infection?


  • Skipper et al. (Annals of Internal Medicine, 2020) sought to determine if hydroxychloroquine is of benefit to individuals with COVID-19 early in their clinical course  


  • Multisite, international, randomized, double-blind, placebo-controlled trial (March 22 through May 20, with final hospital outcomes available June 15, 2020)  
    • 40 states (US) | 3 provinces (Canada)
    • Researchers collected self-reported survey data using the Research Electronic Data Capture (REDCap) system | Outreach traditional and through social media
  • Participants
    • Nonhospitalized | ≤4 days of symptoms with
      • Laboratory-confirmed COVID-19 or COVID-19–compatible symptoms and in contact with COVID-19 positive individual
    • Symptomatic health care workers with high-risk exposure but whose contact had PCR results pending were also included
  • Randomized 1:1 to the following
    • Oral hydroxychloroquine: 800 mg once, followed by 600 mg in 6 to 8 hours, then 600 mg daily for 4 more days
    • Masked placebo
  • Measurements
    • Symptoms and severity at baseline and then at days 3, 5, 10, and 14
    • Assessed using a 10-point visual analogue scale
  • Outcomes
    • The primary end point was changed to an overall symptom severity score over the course of 14 days


  • 423 contributed primary end point data (out of 491 randomized)
    • Median age: 40 years | 56% women | Identified as Black or African American were underrepresented (3%)  
    • Enrolled within 1 day of onset of symptoms: 56% (236 of 423)
  • Change in symptom severity over 14 days did not differ between groups
    • Absolute difference in symptom severity: −0.27 points (95% CI, −0.61 to 0.07 points; P=0.117)
  • There was no difference in proportion of patients with ongoing symptoms at 14 days (P=0.21)
    • Hydroxychloroquine: 24%
    • Placebo: 30%
  • Medication adverse effects were more frequent with hydroxychloroquine (P < 0.001)
    • Hydroxychloroquine: 43%
    • Placebo: 22%
  • There was no significant difference in hospitalization or death (P = 0.29)
    • Hydroxychloroquine: 4 hospitalizations occurred | 1 nonhospitalized death
    • Placebo: 10 hospitalizations (2 non–COVID-19–related) | 1 hospitalized death


  • The authors note that the population was relatively young, with few comorbid conditions and therefore these outcomes may not be generalizable to all population groups | A substantial proportion of patients were enrolled based on symptoms and not SARS-CoV-2 testing (due to limited availability)
  • The authors conclude that

Hydroxychloroquine did not substantially reduce symptom severity in outpatients with early, mild COVID-19

Learn More – Primary Sources:

Hydroxychloroquine in Nonhospitalized Adults With Early COVID-19

CDC Reports on Pregnancy and COVID-19 Outcomes

NOTE: Information and guidelines may change rapidly. Check in with listed references in ‘Learn More – Primary Sources’ to best keep up to date


The CDC now includes a separate page on COVID-19 and pregnancy data (see ‘Learn More – Primary Sources’). The initial dataset is based on the MMWR review (June 26, 2020) and the page will be updates as new data becomes available

Summary of MMWR study


  • CDC receives reports of COVID-19 cases through
    • Electronic standardized case report form or The National Notifiable Diseases Surveillance System
    • Data updated by health departments
    • Case reports for this study: January 22 to June 7 and updated as of June 17, 2020
  • Participants
    • Women aged 15 to 44 years (reproductive age) from 50 states, the District of Columbia, and New York City
    • Lab confirmed SARS-CoV-2 infection
  • Data collected included
    • Demographics | Pregnancy status | Underlying medical conditions | Clinical course | Outcomes (maternal)
  • Missing data
    • To avoid overestimating the risk for adverse outcomes, “Outcomes with missing data were assumed not to have occurred (i.e., if data were missing on hospitalization, women were assumed to not have been hospitalized)”
  • Statistical analysis
    • Outcomes: Logistic regression, using crude and adjusted risk ratios and 95% CIs
    • Risk ratios (RR) adjusted for
      • Age | Presence of underlying chronic conditions | Race/ethnicity


  • Women of reproductive age and positive for SARS-CoV-2: 326,335
  • Pregnancy status
    • 28% (91,412) of all reproductive age women had pregnancy status available | Among those women with pregnancy information, 9% (8,207) were reported as pregnant
  • Symptoms
    • Cough: Similar between pregnant and nonpregnant women (>50%)
    • Shortness of breath: Similar between pregnant and non-pregnant (30%)
    • Pregnant women less frequently reported
      • Headache | Muscle aches | Fever | Chills | Diarrhea
  • Comorbidities
    • More frequently reported in pregnant women
      • Chronic lung disease | Diabetes mellitus | CVD
  • Hospitalization
    • Significantly higher in pregnant women (adjusted)
    • Pregnant: 31.5% | Nonpregnant: 5.8%
    • aRR: 5.4 (95% CI, 5.1 to 5.6)
  • ICU admission
    • Significantly higher in pregnant women (adjusted)
    • Pregnant: 1.5% | Nonpregnant: 0.9%
    • aRR: 1.5 (95% CI, 1.2 to 1.8)
  • Mechanical ventilation
    • Significantly higher in pregnant women (adjusted)
    • Pregnant: 0.5% | Nonpregnant 0.3%
    • aRR: 1.7 (95% CI, 1.2 to 2.4)
  • Maternal mortality
    • There was no difference between groups
    • Pregnant : 0.2% (16 patients) | Nonpregnant: 0.2% (208 patients)
    • aRR: 0.9 (95% CI, 0.5 to 1.5)


  • Limitations include
    • Pregnancy status was missing for approximately 75% of women of reproductive age
    • Data on race/ethnicity, symptoms, underlying conditions, and outcomes were missing “for a large proportion of cases”
    • Data not available for the following
      • Trimester at time of infection was not available
      • Whether hospitalization was related to COVID-19
    • Current routine case surveillance does not capture pregnancy or birth outcomes
  • CDC concludes that

These findings suggest that among women of reproductive age with COVID-19, pregnant women are more likely to be hospitalized and at increased risk for ICU admission and receipt of mechanical ventilation compared with nonpregnant women, but their risk for death is similar

Learn More – Primary Sources:

CDC (MMWR): Characteristics of Women of Reproductive Age with Laboratory-Confirmed SARS-CoV-2 Infection by Pregnancy Status — United States, January 22–June 7, 2020

CDC: Data on COVID-19 During Pregnancy

CDC Who Needs Extra Precautions: People of Any Age with Underlying Medical Conditions

ACOG: Novel Coronavirus 2019 (COVID-19)

Is There a ‘Preeclampsia-Like’ Syndrome in Pregnant Women with COVID-19?


  • There is overlapping symptomatology between preeclampsia (PE) and COVID-19 including liver injury and coagulopathy
    • Being able to differentiate between the two could have significant implications for clinical care as PE with severe features usually requires delivery
  • Mendoza et al. (BJOG, 2020) sought to investigate pregnancies with COVID-19 and determine, based on clinical, ultrasound and biochemical findings if patients with true PE vs ‘PE-like’ features could be distinguished


  • Prospective observational study
    • Tertiary referral hospital
  • Participants
    • Singleton pregnancies
    • Confirmed or suspected COVID-19
    • >20w0d gestation
  • Classified in to two groups: Severe vs nonsevere COVID-19, based on presence of severe pneumonia
  • Aside from clinical outcomes, the following ultrasound and biochemical parameters were also assessed in patients with suspected PE
    • Uterine artery pulsatility index (UtAPI)
    • Angiogenic factors: Soluble fms-like tyrosine kinase-1/placental growth factor (sFlt-1/PlGF)
  • Primary outcome measures
    • Incidence of signs and symptoms related to PE, including
      • Hypertension | Proteinuria | Thrombocytopenia | Elevated liver enzymes | Abnormal UtAPI and increased sFlt-1/PlGF
    • “UtAPI >95th centile for gestational age, and sFlt-1/PlGF values ≥85 (at <34 weeks) or ≥110 (at ≥34 weeks) were considered highly suggestive of underlying placental disease”


  • 42 consecutive pregnancies were recruited
    • Nonsevere: 34
    • Severe (requiring ICU admission): 8
  • Clinical course of severe group
    • Prior to onset of severe pneumonia, all 8 women were normotensive and only 1 patient had elevated UtAPI
  • Median age of severe cases (39.4 years) were significantly higher than nonsevere (30.9 years); p=0.006
  • Following severe pneumonia onset, 6 women (14.3% of total cohort) met PE criteria including
    • New onset hypertension and proteinuria and/or thrombocytopenia and/or elevated liver enzymes
    • No cases met diagnostic criteria in the nonsevere group
    • All required antihypertensive medication
    • Only 1 patient had abnormal LDH level >600 UI/L, sFlt-1/PlGF, and UtAPI
    • 4 cesarean births
      • HELLP syndrome (1 case)
      • Worsening COVID-19 (3 cases)
  • Two cases were still pregnant after recovery from severe pneumonia
    • PE-like syndrome resolved in both cases


  • Pregnant women with severe COVID-19 can develop a PE-like syndrome
  • The authors suggest that only 1 out of the 8 cases demonstrated ultrasound and biochemical features compatible with placental dysfunction
    • PE-like syndrome vs PE could possibly be differentiated based on these biochemical markers (sFlt-1/PlGF, LDH) and Doppler (UtAPI) features
  • Based on the resolution in 2 of the cases, the authors state that

PE-like syndrome might not be an indication for earlier delivery in itself since it might not be a placental complication and could resolve spontaneously after recovery from severe pneumonia.

Learn More – Primary Sources:

Preeclampsia-like Syndrome Induced by Severe COVID-19: A Prospective Observational Study

Commentary: Can COVID‐19 in pregnancy cause preeclampsia?

RECOVERY RCT ALERT: Dexamethasone Reduces COVID-19 Deaths


The ‘Randomised Evaluation of COVid-19 thERapY (RECOVERY) Trial’ is a national program in the UK to study multiple potential therapies for SARS-CoV-2 infection. The program involves thousands of doctors, nurses, pharmacists, and research personnel. The dexamethasone branch of the RECOVERY Trial program was halted on June 8th because the steering committee felt there was sufficient evidence to make a determination whether there was benefit to this therapy. The chief investigators, Professors Horby and Landray, reported the findings on June 16, 2020.

  • The preliminary results found that

Overall dexamethasone reduced the 28-day mortality rate by 17% (0.83 [0.74 to 0.92]; P=0.0007) with a highly significant trend showing greatest benefit among those patients requiring ventilation (test for trend p<0.001)


Randomized controlled trial (RCT)

  • Participants
    • Patients hospitalized with COVID-19
  • Randomization
    • Dexamethasone 6 mg daily (oral or IV) vs usual care alone
  • Primary Outcomes
    • Within 28 days after randomization: Death | Discharge | Need for ventilation | Need for renal replacement therapy
  • Additional data collected
    • Age | Sex | Major co-morbidity | Pregnancy | COVID-19 onset date and severity


  • Dexamethasone group: 2104 patients | Usual care alone: 4321 patients
  • Usual care group
    • 28-day mortality rates
      • Requiring ventilation: 41%
      • Oxygen only: 25%
      • No respiratory intervention: 13%
  • Dexamethasone group: Reduction in deaths vs usual care alone
    • Requiring ventilation: Rate ratio (RR) 0.65 (95% CI, 0.48 to 0.88]; p=0.0003)
    • Oxygen only: RR 0.80 (95% CI, 0.67 to 0.96; p=0.0021)
    • No respiratory intervention: RR 1.22 (95% CI, 0.86 to 1.75; p=0.14)
  • Need to treat
    • Ventilated patients: 1 death would be prevented by treatment of approximately 8 patients
    • Oxygen alone: 1 death prevented by treatment of approximately 25 patients


  • Reduction in deaths for hospitalized patients with COVID-19 with the use of low dose dexamethasone
    • Reduced deaths by one-third in ventilated patients
    • Reduced deaths by 20% for oxygen only patients   
    • No benefit for patients not requiring respiratory support
  • Full report will be published
  • Professor Hornsby, one of the chief investigators states that

…dexamethasone should now become standard of care in these patients. Dexamethasone is inexpensive, on the shelf, and can be used immediately to save lives worldwide

Learn More – Primary Sources:

RECOVERY TRIAL: Low-cost dexamethasone reduces death by up to one third in hospitalised patients with severe respiratory complications of COVID-19

Dexamethasone in Hospitalized Patients with Covid-19 — Preliminary Report (NEJM)

FDA Revokes Hydroxychloroquine and Chloroquine EUA for the Treatment of COVID-19


The FDA has revoked the Emergency Use Authorization (EUA) for chloroquine phosphate and hydroxychloroquine sulfate. Based on the available data, these medications do not appear to be effective in the treatment of COVID-19 and also present harms, specifically related to cardiac arrhythmias.

  • An EUA is different than a full FDA approval
    • EUA based on an FDA evaluation of evidence and risks vs potential or known benefits of “unproven” products during an emergency
  • Chloroquine phosphate and hydroxychloroquine sulfate, donated to the Strategic National Stockpile, received an EUA to be used to treat certain hospitalized patients with COVID-19 when a clinical trial was unavailable, or participation in a clinical trial was not feasible
  • Based on benefits/harms analysis, these medications no longer meet the EUA requirements


  • Research has demonstrated the following regarding hydroxychloroquine and chloroquine (see ‘Related ObG Entries’ below)
    • Hydroxychloroquine showed no benefit on mortality or in speeding recovery (RCT)
    • Suggested dosing regimens for chloroquine and hydroxychloroquine are unlikely to kill or inhibit the virus that causes COVID-19
    • “The totality of scientific evidence currently available indicate a lack of benefit”
  • FDA approved use of chloroquine and hydroxychloroquine
    • Still both FDA-approved to treat or prevent malaria
    • Hydroxychloroquine is also approved to treat autoimmune conditions such as chronic discoid lupus erythematosus, systemic lupus erythematosus in adults, and rheumatoid arthritis

Note: “FDA approved products may be prescribed by physicians for off-label uses if they determine it is appropriate for treating their patients, including during COVID”

Possible Drug Interaction with Remdesivir

  • The FDA also released a warning regarding a potential drug interaction between remdesivir and chloroquine and hydroxychloroquine
  • Data derived from a non-clinical laboratory study demonstrated possible reduction in the antiviral activity of remdesivir activity when co-administered with these medications
  • The FDA is not currently aware of reduced activity in the clinical setting and continues to evaluate data on this subject

Learn More – Primary Sources:

Coronavirus (COVID-19) Update: FDA Revokes Emergency Use Authorization for Chloroquine and Hydroxychloroquine

Coronavirus (COVID-19) Update: FDA Warns of Newly Discovered Potential Drug Interaction That May Reduce Effectiveness of a COVID-19 Treatment Authorized for Emergency Use

Neonatal Infection: COVID-19 and Risk for Vertical Transmission


  • Walker et al. (BJOG, 2020) sought to investigate the risk for vertical transmission in women with COVID-19 around the time of delivery
  • A systematic analysis was performed, including an effort to address duplicate reporting in previous studies


  • Systematic review and critical analysis (Search from April through May, 2020)
    • Authors sought out full text copies of any studies that may be eligible for inclusion
  • Eligibility criteria for studies
    • Pregnant women with confirmed (positive test or high clinical suspicion) COVID-19
    • Case reports or case series | No language restriction
  • Rates of infection were determined for the following
    • Mode of birth (cesarean or vaginal)
    • Breast or formula feeding
    • Rooming in or isolation
  • Studies underwent disambiguation to avoid duplication of patients among different reports


  • 49 studies included
    • 666 neonates | 655 pregnant women
    • 11 twins
  • Infected neonates: 4%
  • Duplicate pregnancies (in Chinese data) were identified and were properly accounted for in subsequent analyses

Mode of Delivery

  • Neonatal infection rates based on mode of delivery
    • Vaginal delivery: 2.7%
    • Cesarean: 5.3%

Breast vs Formula Feeding

  • Among neonates with confirmed COVID-19
    • Breast fed: 7
    • Formula: 3
    • Expressed breast milk: 1
    • Unreported: 17

Rooming In vs Isolation

  • Among neonates with confirmed COVID-19
    • Isolated: 7
    • Rooming in: 5
    • Not reported: 16


  • Overall, there was a low rate of neonatal infection following maternal COVID-19 infection
  • There does not appear to be a greater risk for vertical SARS-CoV-2 transmission based on mode of delivery, breast feeding or rooming in
  • The authors acknowledge limitations including
    • Not all newborns tested for SARS-CoV-2
    • Case series have possibility of bias | More severe cases are more likely to be reported
    • “…disappointing that details of outcome and care” were not available and should be considered a “missed opportunity”
    • Due to low newborn infection rate, ‘n’ of infected neonates is still relatively small and appropriate caution should be used in interpreting the data
  • The authors conclude that

There is no evidence that isolating the baby away from the mother is beneficial if such precautions are taken, and encouraging the baby to spend time with its mother is likely to help with breastfeeding and bonding

We recommend that separation only occurs where this is necessary for clinical indications

Learn More – Primary Sources:

Maternal transmission of SARS‐COV‐2 to the neonate, and possible routes for such transmission: A systematic review and critical analysis

Do Warmer Temperatures Decrease the Incidence of COVID-19?


  • Sehra et al. (Clinical Infectious Diseases, 2020) investigated the effects of temperature, precipitation, and UV Light on community transmission of SARS-CoV-2


  • Observational analysis of case data
  • Data analyzed (January 22 to April 3, 2020)
    • Daily reported cases of SARS-CoV-2 and daily weather patterns across the US
  • Analysis
    • Null hypothesis: There is no association between daily temperatures and COVID-19 spread
    • Modeling techniques were used to investigate whether daily maximum temperature, precipitation, UV Index and the SARS-CoV-2 incidence 5 days later were related
    • Sensitivity analyses to assess transmission lags were performed at 3 days, 7 days and 9 days


  • 974 daily observations
  • Max temperature of >52°F associated with a lower rate of new cases at 5 days
    • Incidence rate ratio (IRR) 0.85 (95% CI 0.76 to 0.96; p = 0.009)


  • Temperature <52°F was inversely associated with case rate at 5 days
    • IRR 0.98 (95% CI 0.97 to 0.99; p = 0.001)
  • Modeling results: Rate of new cases was lower for theoretical states where daily temperature remained >52°F
    • At this temperature threshold, modeling predicted that there would be 23-fewer cases per-million per-day by 25 days of the epidemic

UV Index

  • A 1-unit higher UV index associated with a lower rate at 5 days
    • IRR 0.97(95% CI 0.95 to 0.99; p = 0.004)


  • Precipitation was not associated with a greater rate of cases at 5 days
    • IRR 0.98 (95% CI 0.89 to 1.08; p = 0.65)


  • COVID-19 incidence was lower at warmer vs cooler temperatures
    • Incidence declined with increasing temperature until 52°F
  • The authors state that while statistically significant, the actual association is small and therefore

…unlikely to provide significant effect beyond current strategies for mitigation

…although there is an association between daily temperature and subsequent case volume the disease may continue to spread in the United States even in periods of warmer weather

Learn More – Primary Sources:

Maximum Daily Temperature, Precipitation, Ultra-Violet Light and Rates of Transmission of SARS-Cov-2 in the United States