The virus is getting smarter. Will our vaccines still work?

New coronavirus strains in Brazil and South Africa seem to override antibodies, raising questions about vaccine efficacy

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Manaus is a big city in Brazil with roughly 22 lakh people. The Covid pandemic started there on March 13 last year and spread like wildfire. In May, deaths from Covid peaked around 120 a day. And then, just as it has waned in Mumbai and Delhi, Covid retreated from Manaus. By August, a report in Nature says, daily Covid deaths reduced to “nearly zero” although social-distancing norms had been relaxed.

Experts assumed Manaus had reached “herd immunity”. So, it is surprising that the city is now in the middle of another Covid wave that is worse than the first. On January 14, a city official told The Guardian they had buried 144 bodies on the 10th, 150 on the 11th, 166 on the 12th, and 198 on the 13th. In a typical, non-Covid year, Manaus has only about 30 deaths in a day.

What’s happening in Manaus? How can the virus ravage a city that only a few months ago was believed to have become immune to it?

DANGEROUS MUTATIONS

There’s a growing view that some recent mutations in the coronavirus might be helping it not only spread faster but also reinfect people who have had Covid-19.

Much has been said about the new UK variant, called B.1.1.7 or 501Y.V1, that is much more contagious than the older B.1.1 virus. The good news is that it is not more lethal, and does not seem to infect people who have been vaccinated or infected earlier.

However, two other mutants have sprung up simultaneously and independently in faraway Brazil and South Africa, and both appear to not only spread faster but also infect people who have either received the vaccine or recovered from Covid.