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PeroK said:This Indian variant is a worry. The numbers are small, but if it really can evade the vaccine then we're in trouble.
The new variant observed in India (B.1.651) has two different mutations of concern L452R and E484Q. Mutations at E484 in the B.1.351 variant from South Africa and the P.1 variant from Brazil have previously been suggested to help the virus evade antibody-based immunity in both laboratory studies of the virus and in clinical trials on various vaccines. However, the antibody response is only one arm of the adaptive immune system (which tries to neutralize pathogens before they can infect the body) and it seems like the variants are not able to evade the cellular immune response (which helps the body eliminate pathogens once infected). Indeed, laboratory data suggests that T-cell response to the virus is not affected by any of the variants tested ( B.1.1.7, B.1.351, P.1, and B.1.427/B.1.428). Note that B.1.351 and P.1 share mutations at E484Q with the B.1.651 variant and the B.1.427/B.1.428 variants from California share the L452R mutation with the B.1.651 variant.
Together these suggest that while the variants may be able to infect vaccinated individuals (due to evading antibody-based immunity), the infection is unlikely to result in serious disease (due to pre-existing cellular immunity).
Consistent with this notion, clinical trial data from vaccine trials support the notion that vaccines may show lower protection against infection by variants with mutations at position E484 of the spike protein but are still very effective at preventing hospitalizations and death. For example, https://ir.novavax.com/news-releases/news-release-details/novavax-confirms-high-levels-efficacy-against-original-and-0showed 96% efficacy in the UK but only a 55% efficacy in South Africa (where the B.1.351 variant is widespread). However, in both locations, the vaccine showed 100% protection against severe disease, including all hospitalization and death. Similarly, the Phase 3 trials of the Johnson & Johnson vaccine showed lower protection against infection in Brazil and South Africa versus the US, but similar protection against severe-critical COVID-19. Cohort studies done in Qatar tell a similar story for the Pfizer mRNA vaccine; slightly lower effectiveness at preventing infection (75% from B.1.351 vs 90% for the B.1.1.7 variant which lacks mutation at E484) but still 97% effective at preventing severe, critical or fatal disease.
So far, the vaccines do seem like they should be reasonably protective against hospitalizations and deaths from the new variants. Of course, the more the virus is allowed to continue replicating uncontrolled in various populations across the world, the greater the chance that new variants could continue to evolve.
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