HealthDay News — The 24-week risk for COVID-19 outcomes is slightly lower after vaccination with mRNA-1273 than BNT162b2, according to a study published online Dec. 1 in the New England Journal of Medicine.
Barbra A. Dickerman, Ph.D., from CAUSALab in Boston, and colleagues emulated a target trial using the electronic health records of U.S. veterans who received a first dose of BNT162b2 or mRNA-1273 vaccine between Jan. 4 and May 14, 2021, which was marked by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) B.1.1.7 (alpha) variant predominance. A second target trial involving veterans vaccinated between July 1 and Sept. 20, 2021, was emulated to assess the influence of the B.1.617.2 (delta) variant.
A total of 219,842 participants were included in each vaccine group. The researchers found that the estimated risk for documented infection was 5.75 (95 percent confidence interval [CI], 5.39 to 6.23) and 4.52 (95 percent CI, 4.17 to 4.84) events per 1,000 persons in the BNT162b2 and mRNA-1273 groups, respectively, during 24 weeks of follow-up in a period marked by alpha variant predominance. For BNT162b2 versus mRNA-1273, the excess number of events per 1,000 persons was 1.23 (95 percent CI, 0.72 to 1.81) for documented infection, 0.44 (95 percent CI, 0.25 to 0.70) for symptomatic COVID-19, 0.55 (95 percent CI, 0.36 to 0.83) for COVID-19 hospitalization, 0.10 (95 percent CI, 0.00 to 0.26) for intensive care unit admission for COVID-19, and 0.02 (95 percent CI, −0.06 to 0.12) for death from COVID-19. For documented infection over 12 weeks during delta variant predominance, the corresponding excess risk for BNT162b2 versus mRNA-1273 was 6.54 events per 1,000 persons (95 percent CI, −2.58 to 11.82).
“Although when we look at hundreds of thousands of recipients, mRNA-1273 is marginally more effective than BNT162b2, the death rate among vaccinated persons remains tiny,” write the authors of an accompanying editorial.