sharon sanders
Editor-in-Chief & President
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The omicron variant was different enough from delta, and delta from earlier versions of the virus, that some reinfections were to be expected. But now, omicron seems to be evolving new forms that penetrate immune defenses with relatively few changes to its genetic code.
“This is actually for me a bit of a surprise,” said Alex Sigal, a virologist at the Africa Health Research Institute. “I thought we’ll need a kind of brand-new variant to escape from this one. But in fact, it seems like you don’t.”
An infection with omicron produces a weaker immune response, which seems to wane quickly, compared with infections with previous variants. Although the newer versions of the variant are closely related, they vary enough from an immune perspective that infection with one doesn’t leave much protection against the others — and certainly not after three or four months.
the risks were evident in those who were unvaccinated, had 1 shot, or 2 or more shots prior to the second infection
Booster shots can help, especially when more than 4 months have elapsed from primary vaccination or a third shot.
The Omicron BA.1-specific vaccine booster remedy?
The worry is centered about the immune escape of these subvariants, which was characterized in a recent Nature paper with the conclusion “Together, our results indicate that Omicron may evolve mutations to evade the humoral immunity elicited by BA.1 infection, suggesting that BA.1-derived vaccine boosters may not achieve broad-spectrum protection against new Omicron variants.” That is to say, besides vulnerability to reinfections, the Omicron BA.1 specific vaccines, due to become available this Fall, may not provide enhanced protection as anticipated. BA.4/5 are too different from BA.1 with respect to how our immune system sees them. Even the head of BioNTech has recently warned about the potential for further immune escape and the reduced impact of vaccines, including an Omicron-BA.1 specific one.
