By Maggie Fox
CNN
April 1, 2021
(CNN)The ongoing Phase 3 clinical trial of Pfizer/BioNTech’s coronavirus vaccine confirms its protection lasts at least six months after the second dose, the companies said Thursday.
The question of how long vaccine protection lasts can only be answered once enough time has passed, and while six months of protection is a modest target, it’s longer than previously known. The study is continuing and future updates may reveal more about how long and how strong this protection is.
The vaccine remains more than 91% effective against disease with any symptoms for six months, the companies said. And it appeared to be fully effective against the worrying B.1.351 variant of the virus, which is the dominant strain circulating in South Africa and which researchers feared had evolved to evade the protection of vaccines, the companies said.