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.

SUMMARY:

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.

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• COVID-19 Definitions
• Symptoms
• Those at Risk
• Travel Warnings
• Recommendations for Reporting, Testing, and Specimen Collection
• Healthcare Personnel: Infection Prevention
• Discontinuation of Transmission-Based Precautions
• Hospital Discharge
• Quarantine

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COVID-19 Definitions

• Mild Illness: Individuals who have
  • Any of the various signs and symptoms of COVID-19 (e.g., fever, cough, sore throat, malaise, headache, muscle pain) without shortness of breath, dyspnea, or abnormal chest imaging
• Moderate Illness: Individuals who have
  • Evidence of lower respiratory disease by clinical assessment or imaging and
  • Saturation of oxygen (SpO2) ≥94% on room air at sea level
• Severe Illness: Individuals who have
  • Respiratory frequency >30 breaths per minute
  • SpO2 <94% on room air at sea level (or, for patients with chronic hypoxemia, a decrease from baseline of >3%)
  • Ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2/FiO2) <300 mmHg
  • Lung infiltrates >50%
• Critical Illness: Individuals who have
  • Respiratory failure
  • Septic shock
  • Multiple organ dysfunction

Symptoms

• Incubation period
  • Time from exposure to development of symptoms: 2 to 14 days
  • 97.5% of persons with COVID-19 who develop symptoms will do so within 11.5 days of SARS-CoV-2 infection (see ‘Related ObG Topics’ below)
  • Median time from exposure to symptoms onset: 4-5 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

Comorbidities with ≥1 meta-analysis or systematic review or by review method defined in Scientific Evidence brief

• Cancer
• Cerebrovascular disease
• Chronic kidney disease*
• Chronic lung diseases limited to:
  • Interstitial lung disease
  • Pulmonary embolism
  • Pulmonary hypertension
  • Bronchopulmonary dysplasia
  • Bronchiectasis
  • COPD (chronic obstructive pulmonary disease)
• Chronic liver diseases limited to:
  • Cirrhosis
  • Non-alcoholic fatty liver disease
  • Alcoholic liver disease
  • Autoimmune hepatitis
• Diabetes mellitus, type 1 and type 2*
• Heart conditions (such as heart failure, coronary artery disease, or cardiomyopathies)
• Mental health disorders limited to:
  • Mood disorders, including depression
  • Schizophrenia spectrum disorders
• Obesity (BMI ≥30 kg/m2)*
• Pregnancy and recent pregnancy
• Smoking, current and former
• Tuberculosis

Comorbidities with ≥1 observational study (e.g., cohort, case-control, or cross-sectional)

• Children with certain underlying conditions
• Down syndrome
• HIV (human immunodeficiency virus)
• Neurologic conditions, including dementia
• Overweight (BMI ≥25 kg/m2, but <30 kg/m2)
• Sickle cell disease
• Solid organ or blood stem cell transplantation
• Substance use disorders
• Use of corticosteroids or other immunosuppressive medications

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

• Cystic fibrosis
• Thalassemia

Comorbidities that are supported by mixed evidence (association in at least one meta-analysis or systematic review and additional studies or reviews that reached different conclusions about risk associated with a medical condition)

• Asthma
• Hypertension, possibly*
• Immune deficiencies (except people with moderate to severe immune compromise due to a medical condition or receipt of immunosuppressive medications or treatments)

Footnote:

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

Travel Warnings

• Updated travelers’ warnings can be found within the CDC Novel Coronavirus Summary page below (‘Learn More – Primary Sources’)

KEY POINTS:

Recommendations for Reporting, Testing, and Specimen Collection

Diagnostic 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

Note: CDC does not recommend using antibody testing to diagnose acute infection | Use a viral (nucleic acid or antigen) test to diagnose acute infection

Healthcare Personnel: Infection Prevention

• Healthcare personnel: CDC advises use of
  • Gloves
  • Gowns
  • Airborne precautions
  • Eye protection (e.g., goggles or a face shield)
• Face masks are an acceptable alternative when the supply chain of N95 respirators (or similar respirators that filter inspired air and offer respiratory protection) cannot meet the demand
• If respirators are in short supply, priority should be given to aerosol-generating procedures
• CDC addresses alternatives in the setting of face mask shortages on the page entitled Strategies for Optimizing the Supply of Facemasks (see ‘Learn More – Primary Sources’)
  

Discontinuation of Isolation Following a Positive Test

Symptom-Based

• Isolation may be discontinued if
  • ≥5 days since symptoms first appeared and
  • ≥24 hours have passed since last fever without the use of fever-reducing medications and
  • Symptoms (e.g., cough, shortness of breath) have improved
  • Continue to wear a mask around others for an additional 5 days

Note: Patients who are severely immunocompromised may produce replication-competent virus beyond 20 days after symptom onset or, for those who were asymptomatic throughout their infection, the date of their first positive viral test | Consultation with infectious diseases specialists is recommended | Use of a test-based strategy for determining when Transmission-Based Precautions may be discontinued could be considered

Hospital Discharge

• Patient can be discharged from hospital with COVID-19 when clinically indicated even if not having met criteria for discontinuation of Transmission-Based Precautions
• If not yet met criteria for discontinuation of Transmission-Based Precautions
  • Decision should be made with clinical care team and local or state public health departments
  • Take in to consideration patient’s home situation and whether it is appropriate for home isolation recommendations (e.g., separate bedroom, appropriate caregivers, access to PPE, potential risk to others in the home who may be at risk)

Quarantine

• The purpose of quarantine is to separate someone who might have been exposed to COVID-19 with the goal of preventing transmission to others

Unvaccinated or Incomplete Vaccination  

• (1) Unvaccinated or (2) >6 months from Second mRNA Dose and not Boosted or (3) >2 Months after the J&J Vaccine and not Boosted
  • Quarantine for 5 days
  • Strict mask use for an additional 5 days

Note: If 5-day quarantine is not feasible, always wear a well-fitting mask when around others for 10 days

Vaccinated with Complete Primary Series (with Booster if Appropriate)

• (1) Completed Primary mRNA Vaccine Series Within Last 6 Months or (2) Completed Primary J&J Vaccine Within Last 2 Months or (3) Have Received Booster
  • Quarantine following an exposure is not required
  • Wear a mask for 10 days after the exposure.
  • Best practice: Test for SARS-CoV-2 at day 5 after exposure

Note: If symptoms occur, quarantine immediately until a negative test confirms symptoms are not attributable to COVID-19

Learn More – Primary Sources:

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

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

CDC: Interim Clinical Guidance for Management of Patients with Confirmed Coronavirus Disease (COVID-19)

CDC: Discontinuation of Transmission-Based Precautions and Disposition of Patients with COVID-19 in Healthcare Settings (Interim Guidance)

CDC Coronavirus Disease 2019: Guidelines for Clinical Specimens

CDC: Interim U.S. Guidance for Risk Assessment and Work Restrictions for Healthcare Personnel with Potential Exposure to COVID-19

CDC: Coronavirus Disease 2019 Information for Travel

Clinical Questions about COVID-19: Questions and Answers

CDC: Strategies for Optimizing the Supply of Facemasks

Interim Infection Prevention and Control Recommendations for Healthcare Personnel During the Coronavirus Disease 2019 (COVID-19) Pandemic

CDC: Implementing Home Care

CDC: Quarantine and Isolation

WHO: Novel coronavirus Information Page

JAMA: Coronavirus Disease 2019

FDA: Coronavirus Disease 2019

BMJ: Coronavirus Updates

Lancet: Coronavirus Hub

NEJM: 2019 Novel Coronavirus

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

CDC: Standard Precautions

CDC: Contact and Airborne Precautions

CDC: Middle East Respiratory Syndrome (MERS)

CDC: Severe acute respiratory syndrome (SARS)

JAMA: What Is a Pandemic?

Related ObG Topics: