Covid variants will not get less virulent with time: Experts on how Omicron BA2.12.1, differs from BA.4, BA.5

Covid variants will not get less virulent with time: Experts on how Omicron BA2.12.1, differs from BA.4, BA.5

Unlike BA2.12.1, BA.4 and BA.5 have not shown enhanced entry to cells.

Issuing a warning for Omicron BA2.12.1, experts have revealed that it is far more transmissible than BA.4 and BA.5 subvariants that are dominant in South Africa. And many who are vaccinated or even boosted are now infected with the variant. Regarding the next variant, they said, “it is not true that variants will get less virulent over time."

Eric Topol, physician and scientist, who tweeted about the recent finding, also posted a paper on the topic that pointed out that BA2.12.1 has a substantial transmissibility advantage beyond BA.2, which was already 30% more transmissible than BA.1.

How transmissible is Omicron BA2.12.1?

The study also showed that Omicron BA2.12.1 has a substantial transmissibility advantage beyond BA.2, which was already 30% more transmissible than BA.1, and reduced cross-immunity to BA.1 such that the people who had Omicron BA.1 infections (estimated to be at least 40% of Americans) may be susceptible to reinfections by this variant.

“Indeed, the Omicron-specific vaccines that use the BA.1 spike structure, which are in clinical trials and due to read out in the next couple of months, may not fulfill their promise with a variant that carries such immune escape properties."

What are the differences between BA2.12.1 and BA.4 and BA.5?

The study also makes a relevant comparison between BA.2.12.1 and the BA.4 and BA.5 variants (which share the same spike protein sequence), which have become dominant in South Africa.

Their (BA.4 and BA.5) increase in transmissibility does not appear to be as much as BA2.12.1, but their immune escape, relative lack of cross-reactive immunity to BA.1 and some increase resistance to monoclonal antibodies is similar to BA2.12.1. Unlike BA2.12.1, BA.4 and BA.5 have not shown enhanced entry to cells.

The study also pointed out the fact that it is concerning that there is significant drop in protection ‘from hospitalization even with 3-shots from prior vaccine effectiveness (pre-Omicron) well above 90%.’

Covid variants will not get less virulent with time: Experts on how Omicron BA2.12.1, differs from BA.4, BA.5
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A recent report suggested with BA.1 the durability of that protection may be shorter. We have no data yet for vaccine effectiveness vs BA2.12.1 or BA.4/BA.5, the study said.

How virulent will be the next variant?

Pointing that we will certainly get through the BA.2.12.1 challenge, the authors said there will always be the question of what's coming next. They also said, there is no reason to think that variants will get less virulent over time

“The problem that lies ahead is the many paths by which yet another noxious variant can show up. To anticipate this next Greek letter variant, we need broad neutralizing antibodies, vaccines that are protective across the beta-coronavirus or sarbecovirus family," the study said.

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