New Covid Boosters’ Protection Waned After Two Months, Study Says

Covid-19 bivalent boosters’ protection against death and hospitalization in elderly people began waning as soon as two months after vaccination, according to a preprint study.

The findings build on previous reports about the effectiveness of updated boosters from Moderna Inc. and Pfizer Inc., which showed the shots sharply reduced risks of severe Covid in older adults, but didn’t assess how long protection lasted. The new report, written by researchers who looked at data from a Finnish patient registry, has not yet been peer-reviewed and was published as a preprint in the server MedRxiv.

“Because we found signs of waning already after 60 days since bivalent vaccination, additional boosters for the elderly could be an option at some time point in the future,” the authors wrote. “However, the need for further boosting should also be considered in the light of the epidemic situation and economic analyses.”