BBCNEWS BBC News December 13, 2021 21:33:00
To 12 week pinch point was really the earliest and latest time you could involve people in the trial and still get the data to thejcvi from the beginning of september so we had to allow that period of time after the second dose to give people after the second dose to give people a third dose and that, then enough time to take people's blood samples and get them to the lab so they the jcvi chose to get the boosters initially at six months that is because normally waiting a bit longer in any vaccines three doses is a better thing to do but when the new variant has come along and there is an urge...
Source: archive.org