“Abstract: Studies have reported reduced natural SARS-CoV-2 infection- and vaccine-induced neutralization against Omicron BA.4/BA.5 compared with earlier Omicron subvariants. We conducted a test-negative case–control study evaluating mRNA-1273 vaccine effectiveness (VE) against infection and hospitalization with Omicron subvariants. The study included 30,809 SARS-CoV-2 positive and 92,427 SARS-CoV-2 negative individuals aged ≥18 years tested during 1/1/2022-6/30/2022…
Results: … In analyses of 3-dose VE (versus unvaccinated) against infection with Omicron subvariants by time since vaccination, the 3-dose VE against BA.1 ranged from 85.8% (95% confidence interval [CI] 82.7%, 88.3%) in the 14-30 days after the third dose to 54.9% (95% CI 35.6%, 68.4%) >150 days after the third dose (Fig. 2, Supplementary Table 2a). VE for these two time intervals, respectively, was 61.0% (95% CI 27.6%, 79.0%) and -24.9% (95% CI -32.3%, -16.7%) for BA.2, excluding BA.2.12.1; 82.7% (95% CI 44.2%, 94.7%) and -26.8% (95% CI -34.6%, -18.0%) for BA.2.12.1; 72.6% (95% CI - 54.7%, 96.6%) and -16.4% (95% CI -35.8%, 8.2%) for BA.4; and 90.6% (95% CI 30.6%, 98.7%) and -17.9% (95% CI -29.6%, -4.2%) for BA.5. We also present the relative VE (rVE) comparing 3 doses to 2 doses against Omicron subvariants by time since vaccination (Fig. 2, Supplementary Table 2b). In general, we observed consistent incremental protection of 3 doses versus 2 doses in the 14-90 days after the third dose, other than against BA.4, which had a small number of cases and wide CI. The incremental benefit in protection decreased by time since the third dose. For BA.5, the 95% CI of rVE included 0 after >90 days after the third dose.”
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