December 24. Booster protection against symptomatic illness caused by the Omicron variant dropped by up to 25% within 10 weeks, new real-world data found — though it’s not yet clear whether everyone may need further doses in 2022.
The UK Health Security Agency said protection against symptomatic COVID-19 caused by the variant dropped from 70% to 45% after a Pfizer booster for those initially vaccinated with the shot developed by Pfizer with BioNTech.
In the same analysis published on Thursday, the agency found the effectiveness of Moderna’s booster paired with two doses of the Pfizer vaccine held at 70% to 75% for up to nine weeks, though not many people in the study received this regimen, which could affect the accuracy of the finding.
For those fully vaccinated with AstraZeneca’s vaccine, booster effectiveness dropped from 60% to 35% with a Pfizer booster and to 45% with a Moderna booster after 10 weeks, the UKHSA said.
Eric Topol, the director of the Scripps Research Translational Institute, tweeted on Thursday that the UK findings were a “replication” of what had been seen in Israel.