Comparative Effectiveness of Moderna, Pfizer-BioNTech, and Janssen (Johnson & Johnson) Vaccines in Preventing COVID-19 Hospitalizations Among Adults Without Immunocompromising Conditions — United States, March–August 2021

Outbreak of SARS-CoV-2 B.1.617.2 (Delta) Variant Infections Among Incarcerated Persons in a Federal Prison — Texas, July–August 2021

“…Three of the four hospitalizations and the only death occurred in unvaccinated persons. These findings are consistent with a previous study in which vaccination with a COVID-19 mRNA vaccine (Pfizer-BioNTech or Moderna) reduced the risk for hospitalization associated with Delta variant infection (6). These findings reinforce the critical importance of vaccination in reducing risk for severe illness and death from SARS-CoV-2 Delta variant infections, particularly in congregate settings.…”

“…In addition, attack rates in persons without previous infection were higher among Pfizer-BioNTech recipients than among Moderna recipients. In a recent study, the Moderna vaccine was found to be more effective at preventing COVID-19-related hospitalizations among U.S. adults without immunocompromising conditions (6). In this outbreak, attack rates were also higher in persons who were vaccinated ≥4 months before the outbreak compared with persons vaccinated more recently.…”

Predicting COVID-19 Vaccine Efficacy from Neutralizing Antibody Levels

“…Our data also shows a clear trend that single dose J&J vaccinated individuals produce substantially less NAbs compared to fully vaccinated Pfizer and Moderna subjects which would be expected to result in lower vaccine efficacy for SARS-CoV-2 infection. These results are consistent with Phase 3 clinical trial results as well as a recent report from the CDC19 that demonstrated 32.7% breakthrough infections for fully vaccinated J&J participants, compared to just 17.3% and 11.3% for fully vaccinated Pfizer and Moderna, respectively. The low level of starting NAbs for J&J vaccinated individuals is concerning, especially considering the ~4-fold reduced neutralizing efficacy of vaccine antibodies for the Delta variant compared to WT COVID-19.…”

Product-specific COVID-19 vaccine effectiveness against secondary infection in close contacts, Navarre, Spain, April to August 2021

“…Our findings are consistent with previous studies that reported high effectiveness of full COVID-19 vaccination in preventing hospitalisations [ 9 - 11 ] and moderate VE in preventing symptomatic and asymptomatic SARS-CoV-2 infection [ 12 , 13 ]. However, few studies evaluated VE for specific products [ 11 , 14 ].…”