We found that recipients of the Pfizer vaccine — those who’ve had two doses — have about five-to-six-fold lower amounts of neutralising antibodies; now these are the sort of gold standard private security antibodies of your immune system, which block the virus from getting into your cells in the first place. So we’ve found that that’s less for people with two doses; we’ve also found that for people with only one dose of the Pfizer jab that they are less likely to have high levels of these antibodies in their blood. And perhaps most importantly for all of us going forward is that we see that the older you are the lower your levels are likely to be, and the time since you’ve had your second jab — as that time goes on — the lower your levels are also likely to be. So that’s telling us that we’re probably going to need to be prioritising boosters for older and more vulnerable people coming up soon, especially if this new variant spreads.
Dr David Bauer, Francis Crick Institute
