[TLO]

Originally Posted by lawrenceRaider

The two dominant strains, B4 and B5 are 4-5 times more resistant to antibodies from the vaccine as B1 was, and they don't seem to have any response to B1 antibodies. That second bit I may have misunderstood.

https://www.statnews.com/2022/06/29/...e-composition/

Moderna and Pfizer executives have claimed that the Omicron vaccines will be protective for longer. That may be true, but how long is longer? A few weeks? A month or two? Again, detailed modeling of the data might provide important information. It’s important to be sure that changing the booster vaccine to include the Omicron sequence offers enough of an advantage to justify the cost and complexity associated with making the switch.

The reason why the Omicron and earlier variant boosters are little or no better than a standard booster is rooted in immunology. The immune system responds to the first sight of the viral spike protein by making neutralizing antibodies and by starting to lay down memory cells that are an archive of what it is seeing. Those memory cells improve over a multi-month period and are then triggered into action when the immune system reencounters the spike protein, either as an infection or in a booster vaccination. The resulting neutralizing antibody response doesn’t appear to depend very much on whether the boost was with the original sequence, the Beta sequence, the Delta sequence, or the Omicron sequence — all are about equally as good at reawakening immune memory cells. The Omicron vaccines also seem to elicit some neutralizing antibodies that are unique to that variant and that make a minor contribution to the overall response. It’s possible that component could improve over time or after additional boosts, but we have no data to evaluate.

Because no one can predict how SARS-CoV-2 will further evolve, there’s no way to tell whether one or more Omicron-based boosts over the next year would be beneficial against what may emerge. What is known is that the increasingly prevalent BA.4 and BA.5 variants are even more resistant to neutralizing antibodies, typically by three- or four-fold, than the now-vanished BA.1 variant on which the Omicron vaccines are based. The trend toward greater resistance of neutralizing antibodies may well worsen.