What is the scientific evidence for booster jabs being moved to three months after the primary vaccines, instead of six months?

[ASinisterPlot]

It was previously advised (presumably by scientists) that there should be a six-month gap between the 2nd primary vaccine and the first booster. Is the three-month gap a knee-jerk response by government or has the scientific evidence changed?

I can't find any information on this anywhere, but maybe someone here knows.

This is exactly what I’m worried about and why I won’t be having my booster until February when it’s due, unless we see evidence otherwise.

This article doesn’t answer your question specifically
BBC explanation about boosters
But it does explain why with a new variant circling it’s a good idea to have one as soon as you can. The original advice, tested in the first trials, was 3 weeks between doses for Prizer and 4 for moderna so 12 weeks is a safe gap.

I think the point is that there isn't enough time to wait 6 months due to the rapid spread of Omicron. On balance its better to bring it forward in order to have the maximum defence now. In any case this might be a moot point as I gather demand has gone through the roof hence it might be difficult to get a booster at the 3 month point if you haven't already booked one.

I'm waiting too - Omicron isn't known yet to be serious so I'll hold off.

I read in the paper that having your third jab after three months raises your protection against Omicron from 30% to 60% or similar. Based on the data they have so far.

Thanks FlyingFlamingo. That's helpful.

Also, I just realised my user name may make me look like a vaccine conspiracy theorist! I'm not (I've happily had my vaccines) - I just couldn't find anything on why the advice changed from six months to three.

I think the CovBoost study was done on 3 months gap so that's what the data are available (not 100% sure but I think that's what I read). I'm not sure why 6 months was chosen initially, maybe just to spread things out a bit.