Effectiveness of mRNA-1273, BNT162b2, and JNJ-78436735 COVID-19 Vaccines Among US Military Personnel Before and During the Predominance of the Delta Variant (original) (raw)

IMPORTANCE No studies to date have evaluated the effectiveness of 3 COVID-19 vaccines in the US military population, especially during the circulation of the SARS-CoV-2 Delta (B.1.617.2) variant. OBJECTIVE To estimate the effectiveness of the mRNA-1273, BNT162b2, and JNJ-78436735 vaccines among US military personnel before and during the predominance of the Delta variant in the US. DESIGN, SETTING, AND PARTICIPANTS This case-control study was conducted among all unvaccinated and fully vaccinated US military personnel who had a documented SARS-CoV-2 test performed in the US between January 1 and September 24, 2021. Individuals were identified using Department of Defense (DOD) electronic medical, laboratory, and surveillance databases. The pre-Delta period was defined as January 1 to May 31, 2021, and the Delta period as June 19 to September 24, 2021. Case individuals were defined by a positive polymerase chain reaction SARS-CoV-2 test result or a positive antigen test result with symptoms. Control individuals had at least 1 negative SARS-CoV-2 test result. EXPOSURES COVID-19 vaccination with the mRNA-1273, BNT162b2, or JNJ-78436735 vaccine, assessed from DOD electronic vaccination records. MAIN OUTCOMES AND MEASURES COVID-19 vaccine effectiveness overall, by vaccine type, and by outcome stratified by the pre-Delta and Delta periods in the US. Vaccine effectiveness was estimated as 100 × (1 − odds ratio) in a logistic regression model with adjustment for potential confounders. RESULTS The cohort included 441 379 individuals, with 290 256 in the pre-Delta period (236 555 [81%] male; median age, 25 years [range, 17-68 years]) and 151 123 in the Delta period (120 536 [80%] male; median age, 26 years [range, 17-70 years]). Adjusted vaccine effectiveness of all vaccines was significantly higher during the pre-Delta period (89.2%; 95% CI, 88.1%-90.1%) compared with the Delta period (70.2%; 95% CI, 69.3%-71.1%) for all outcomes, an overall decrease of 19%. mRNA-1273 vaccine effectiveness was highest in the pre-Delta (93.5%; 95% CI, 91.9%-94.7%) and Delta (79.4%; 95% CI, 78.3%-80.4%) periods for all outcomes, whereas the JNJ-78436735 vaccine had the lowest effectiveness during the pre-Delta (81.8%; 95% CI, 74.2%-87.1%) and Delta (38.3%; 95% CI, 34.5%-41.9%) periods. Effectiveness for all vaccines during both periods was higher for symptomatic infection and hospitalization among individuals with SARS-CoV-2 infection. (continued) Key Points Question Did the effectiveness of the mRNA-1273, BNT162b2, and JNJ-78436735 COVID-19 vaccines change among US-based military personnel before and during the predominance of the SARS-CoV-2 Delta (B.1.617.2) variant? Findings In this case-control study of 441 379 active US military personnel, overall COVID-19 vaccine effectiveness decreased by 19% from the pre-Delta to the Delta period. JNJ-78436735 had the lowest overall vaccine effectiveness in the pre-Delta (81.8%) and Delta (38.3%) periods. Meaning In this study, COVID-19 vaccine effectiveness decreased among US-based military personnel during the time of SARS-CoV-2 Delta variant predominance, especially for recipients of the JNJ-78436735 vaccine; this finding supports the use of booster doses to increase effectiveness.