BACKGROUND AND PURPOSE:

• Self et al. (CDC MMWR, 2021) assessed vaccine effectiveness (VE) of the three available vaccines in preventing COVID-19 hospitalization, and compared serum antibody levels after full vaccination with the Moderna, Pfizer-BioNTech, or Janssen COVID-19 vaccine

METHODS:

• Case-control analysis (during March 11 to August 15, 2021)
• Population
  • ≥18 years
  • Without an immunocompromising condition
  • Hospitalized at 21 U.S. hospitals across 18 states
• Exposures
  • Case-patients: Admitted to a hospital with COVID-19–like illness and a positive SARS-CoV-2 RT-PCR or antigen test result
  • Control-patients: Admitted to a hospital with negative SARS-CoV-2 RT-PCR test result
• Study design
  • In addition to VE case-control analysis, additional postvaccine antibody analysis was conducted against three SARS-CoV-2 antigens (spike protein, the spike receptor binding domain [RBD], and nucleocapsid)
  • IgG levels reported in international binding antibody units (BAU)
• Primary outcome
  • VE against COVID-19 hospitalization

RESULTS:

• 1682 COVID-19 patients | 2007 control patients
  • Fully vaccinated with Moderna: 12.9%
  • Fully vaccinated with Pfizer: 20.0%
  • Fully vaccinated with Janssen: 3.1%
  • Nonvaccinated: 64.0%
• VE against COVID-19 hospitalization was higher for the Moderna vaccine than for the Pfizer vaccine (P=0.011)
  • Moderna VE: 93%
  • Pfizer VE: 88%
• VE for both mRNA vaccines were higher than for the Janssen vaccine (all P<0.001)
  • Janssen VE: 71%
• VE remained consistent over time for Moderna, but declined significantly for Pfizer
  • Moderna (P=1.000)
    • 14 to 120 days (median 66 days) after second dose: 93%
    • >120 days (median 141 days): 92%
  • Pfizer (P<0.001)
    • 14 to 120 days (median 69 days) after second dose: 91%
    • 120 days (median 143 days): 77%
• 100 healthy volunteers for antibody testing
  • Moderna: 32 participants
  • Pfizer: 51 participants
  • Janssen: 17 participants
• Anti-RBD levels were higher in participants vaccinated with the Moderna vaccine compared with the other two vaccines
  • Moderna
    • Median (IQR) 4333 (3134 to 7197) BAU/mL
  • Pfizer (P=0.033)
    • Median (IQR) 3217 (2048 to 4668) BAU/mL
  • Janssen (P<0.001)
    • Median (IQR) 57 (26 to 94) BAU/mL
• Anti-spike IgG levels in participants vaccinated with the Moderna vaccine were not significantly different from those in Pfizer recipients, but were significantly higher than those who received Janssen
  • Moderna
    • Median (IQR) 3236 (2125 to 4975) BAU/mL
  • Pfizer (P=0.217)
    • Median (IQR) 2983 (1954 to 4059) BAU/mL
  • Janssen (P<0.001)
    • Median (IQR) 59 (30 to 104) BAU/mL

CONCLUSION:

• Moderna and Pfizer vaccines had a VE against COVID-19 hospital admission of 93% and 88% respectively
  • Janssen’s VE was somewhat lower, at 71%
• Antibody levels were similarly elevated in those that received an mRNA vaccine, while Janssen vaccine recipients had significantly lower titers
• Pfizer vaccine protection declined 4 months after vaccination
• The Moderna vaccine produced higher postvaccination anti-RBD antibody levels than Pfizer, which may be due to higher mRNA content in Moderna, or the timing between doses

Learn More – Primary Sources:

Comparative Effectiveness of Moderna, Pfizer-BioNTech, and Janssen (Johnson & Johnson) Vaccines in Preventing COVID-19 Hospitalizations Among Adults Without Immunocompromising Conditions

Related ObG Topics:

COVID-19 mRNA Vaccine Effectiveness in the Real World Including in Those Partially Immunized

COVID-19 Vaccine Effectiveness: Cases and Hospitalizations in New York by Vaccination Status

How Effective are Pfizer and AstraZeneca Vaccines vs the Delta Variant?