Pfizer/BioNTech COVID-19 vaccine effectiveness drops after 6 months, research reveals


Oct 4 (Reuters) – The effectiveness of the Pfizer Inc (PFE.N)/BioNTech SE vaccine in stopping an infection by the coronavirus dropped to 47% from 88% six months after the second dose, in response to knowledge printed on Monday that U.S. well being businesses thought-about when deciding on the necessity for booster pictures.

The knowledge, which was printed within the Lancet medical journal, had been beforehand launched in August forward of peer overview.

The evaluation confirmed that the vaccine’s effectiveness in stopping hospitalization and demise remained excessive at 90% for a minimum of six months, even towards the extremely contagious Delta variant of the coronavirus.

The knowledge means that the drop is because of waning efficacy, reasonably than extra contagious variants, researchers stated.

Researchers from Pfizer and Kaiser Permanente studied digital well being information of roughly 3.4 million individuals who have been members of Kaiser Permanente Southern California between December 2020 – when the vaccine first turned accessible – and August of 2021.

“Our variant-specific analysis clearly shows that the (Pfizer/BioNTech) vaccine is effective against all current variants of concern, including Delta,” stated Luis Jodar, senior vp and chief medical officer at Pfizer vaccines.

A possible limitation of the research was a scarcity of knowledge on adherence to masking pointers and occupations within the research inhabitants, which may have affected frequency of testing and chance of publicity to the virus.

Vaccine effectiveness towards the Delta variant was 93% after the primary month, declining to 53% after 4 months. Against different coronavirus variants, efficacy declined to 67% from 97%.

“To us, that suggests Delta is not an escape variant that is completely evading vaccine protection,” stated research chief Sara Tartof with Kaiser Permanente Southern California’s Department of Research & Evaluation.

“If it was, we would probably not have seen high protection after vaccination, because vaccination would not be working in that case. It would start low, and stay low.”

Testing for variants is extra more likely to fail in vaccinated people, which may result in overestimation of variant-specific effectiveness within the research, the authors cautioned.

The U.S. Food and Drug Administration has approved the usage of a booster dose of the Pfizer/BioNTech vaccine for older adults and a few Americans at high-risk of getting contaminated. Scientists have referred to as for extra knowledge on whether or not boosters must be really useful for all.

Reporting by Manas Mishra in Bengaluru; Editing by Bill Berkrot

A patient receives their coronavirus disease (COVID-19) vaccine booster during a Pfizer-BioNTech vaccination clinic in Southfield, Michigan, U.S., September 29, 2021.  REUTERS/Emily Elconin/File Photo