Effectiveness of full vaccination against SARS-CoV-2 infections caused by the delta variant or other variants wanes more quickly
WEDNESDAY, Oct. 6, 2021 (HealthDay News) — The BNT162b2 (Pfizer-BioNTech) vaccine is highly effective against COVID-19-related hospital admission up to six months after full vaccination, according to a study published online Oct. 4 in The Lancet.
Sara Y. Tartof, Ph.D., from Kaiser Permanente Southern California in Pasadena, and colleagues examined overall and variant-specific effectiveness of BNT162b2 against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections and COVID-19-related hospital admissions. Data were included for 3,436,957 individuals between Dec. 14, 2020, and Aug. 8, 2021.
The researchers found that effectiveness against SARS-CoV-2 infections was 73 percent for fully vaccinated individuals and 90 percent against COVID-19-related hospital admissions. There was a decline noted in effectiveness against infections, from 88 percent during the first month after full vaccination to 47 percent after five months. Vaccine effectiveness against infections of the delta variant was 93 percent during the first month after full vaccination and decreased to 53 percent after four months. Effectiveness against other variants declined from 97 percent during the first month after full vaccination to 67 percent at four to five months. For all ages, vaccine effectiveness against hospital admissions for infections with the delta variant was high overall up to six months (93 percent).
“Our study confirms that vaccines are a critical tool for controlling the pandemic and remain highly effective in preventing severe disease and hospitalization, including from the delta and other variants of concern,” Tartof said in a statement. “Protection against infection does decline in the months following a second dose.”
Several authors disclosed financial ties to pharmaceutical companies, including Pfizer, which funded the study.
Copyright © 2021 HealthDay. All rights reserved.