Table 1.

Effect of Vaccination on Total SARS-CoV-2 Infection Risk

Vaccine	Sample Size	Setting	Vaccine Efficacy/Effectiveness
Randomized Controlled Trials
mRNA-1273 [5]	30 420	United States	61% (95% CI 31–79%) reduction in asymptomatic infection prior to second dose (15 cases vs. 39 cases) relative to 85% reduction (95% CI 66–93%) in symptomatic infection
ChAdOx1 nCoV-19 [7]	3744 (subgroup)	England and Wales	55.7% (95% CI 41.4–66.7%) reduction in all infections (68 vs. 153 cases) relative to 70.4% reduction (95% CI 54.8–80.6%) in symptomatic infection
AD26.COV2.S [9]	2650 (subgroup)	Argentina, Brazil, Chile, Colombia, Mexico, Peru, South Africa, and the United States	65.5% (95% CI 39.9–81.1%) reduction in asymptomatic infections (18 vs. 50 cases) relative to 66.5% reduction (95% CI 55.5–75.1%) in symptomatic infection
Observational Studies with Control of Confounding
BNT162b2 [12]	23 324	Healthcare workers in UK	85% reduction (95% CI 74–96%) in all SARS-CoV-2 infections 7 days after 2nd dose
mRNA-1273 and BNT162b2 [13]	3975	Healthcare workers, first responders, and frontline workers in the United States	91% reduction (95% CI 76–97%) in all SARS-CoV-2 infections after full vaccination
ChAdOx1 nCoV-19 or BNT162b2 [3]	373 402	Community members in UK	70% reduction (95% CI 62–77%) in all SARS-CoV-2 infections after the second dose
mRNA-1273 or BNT162b2 [15]	39 156	Pre-procedural screening in the United States	80% reduction (95% CI 56–91%) in all positive tests
ChAdOx1 nCoV-19 or BNT162b2 [16]	10 412	Elderly residents of Long-term care facilities in UK	62% reduction (95% CI 23–81%) in all SARS-CoV-2 infections 35 days after the first dose