**Pfizer Vaccine Seen as 33% Effective Against Omicron After Two Doses, May Wane Sooner**
**By Bloomberg**
**(Bloomberg) –** Pfizer Inc. and BioNTech SE’s Covid-19 vaccine is estimated to be about 33% effective against infection from the omicron variant of the coronavirus two weeks after a second dose, a finding that suggests the inoculation’s protection wanes more quickly than against other strains.
The estimate is based on an analysis of preliminary data from the companies, which collected nasal and blood samples from people who received two doses of their vaccine. The findings, which have not yet been peer-reviewed, were presented to U.S. health officials on Wednesday.
It showed that vaccine efficacy against infection waned to 33% from 70% by six months in people without prior infection, and to 29% from 85% in those who had previously been infected, lead researcher Ugur Sahin said in a briefing with reporters.
The decline in effectiveness against omicron among those without prior infection was .
