He explained this in more detail in a review article in Cell called Omicron’s Message on Vaccines, as well as a research paper on his own lab’s work in Science Immunology. The first two mRNA shots might have been too close together to allow these B-cells to mature, he said, and so the longer interval to the third shot might explain why those who received it make antibodies that neutralize omicron 20 to 30 times better than the initial shots. But without any further shots, the circulating antibodies that had provided an earlier line of defense do almost nothing to stop an infection with omicron and its sub-variants BA.2 and BA.2.12.1.
They won’t stop you from getting sick, but they will kick in to prevent the disease from becoming severe. The first two shots (or one shot of the J&J vaccine) still protect most of us against severe disease because our bodies retain virus-fighting T-cells, which are a sort of backup line of defense. The most mature B-cells carry different mutations that allow them to produce antibodies with more diversity, improving the odds that some will be good at attacking the new variants that keep evolving. The way he explains it, antibody-making cells, called B-cells, can grow to different levels of maturity. It also improves the quality of our antibodies. He told me that earlier studies from his lab and others show that the third mRNA shot gives most of us more than a temporary increase in antibodies. Though a third shot is obviously not 100% effective - nothing in medicine is - it vastly improves your odds of avoiding omicron, which is the family of variants that have dominated since the end of last year, said Duane Wesemann, an immunologist who is heading the study.
I’ll find out soon, since I just gave a blood sample for a study that can decipher this and a lot more from the mix of antibodies I carry. About one in four Americans still haven’t been infected with Covid-19, according to some estimates - and as far as I know, I’m one of them, though it’s also possible I had an asymptomatic case. That’s why some people are getting Covid two or three times and others have never gotten it at all. Some people’s antibodies hold up better than others and work better fighting the current variants. But figuring that out won’t be easy, since there are factors besides age and being immune-compromised that matter.
It might be clearer to redefine full vaccination to encompass two, three or four shots depending on various individual risk factors.
“I’m confused, and I’m on the FDA advisory committee”, said Paul Offit, director of the vaccine education center at the Children’s Hospital of Philadelphia, on a recent video conference.Īnother part of the problem is the term booster, he said. That variability could be causing confusion over who should get how many booster shots and when. One reason may be that we’re all over map in our risk of getting infected. That booster shot improves your odds of avoiding even mild omicron. Fewer than half of eligible Americans have received a third Covid vaccine shot despite clear evidence of its benefit.