“Results: Estimated BNT162b2 [Pfizer] effectiveness against any SARS-CoV-2 infection was negligible in the first 2 weeks after the first dose. It increased to 36.8% (95% confidence interval [CI], 33.2 to 40.2) in the third week after the first dose and reached its peak at 77.5% (95% CI, 76.4 to 78.6) in the first month after the second dose. Effectiveness declined gradually thereafter, with the decline accelerating after the fourth month to reach approximately 20% in months 5 through 7 after the second dose…
Discussion: … By far the dominant variant during the study was B.1.351 [beta], and a similar pattern of waning of protection was observed for B.1.1.7 [alpha], B.1.351, and B.1.617.2 [delta].”
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