Kaiser Permanente study assessed Pfizer BioNTech COVID-19 vaccine effectiveness against infection, hospitalization, and death up to 8 months after vaccination. A Kaiser Permanente study published today in The Lancet Regional Health.
Americas found that one month after a third dose, the Pfizer BioNTech COVID-19 vaccine effectiveness is higher for preventing infection and hospitalization than two doses of the vaccine after 1 month. They also found that the effectiveness of the 2 doses of Pfizer BioNTech vaccine versus 3 doses, we see a benefit with 3 doses that exceeds that achieved with 2 doses alone. .
To assess effectiveness, this research study evaluated electronic health records of 3.1 million members of Kaiser Permanente in Southern California from December 14, 2020, to December 5, 2021. During the study period, 197,535 (6.3%) patients were infected with SARS-CoV-2, and of those, 15,786 (8%) were admitted to the hospital. During the study period, the predominant variant was delta, and not omicron.