SALIENT FEATURES-  Benefit of vaccination for reducing incidence of SARS-CoV-2 infections is not clear. Infection rate with Omicron was compared in person who received booster dose and those who did not. 74 165 person-days fully boosted individuals and 10 890 person-days (vaccinated but not boosted) were compared.

The infection rate in boosted persons were significantly less as compared to those who did not receive booster. 93% were confirmed to be Omicron infection.