UK Elevates B.1.617 to Variant of Concern: Can it Impact Vaccines?
FIT speaks with Prof Ravindra Gupta, a clinical microbiologist at the University of Cambridge.
As UK's regulatory body Public Health England (PHE) elevates the status of a sub-lineage of the 'Indian Variant' B.1.617 of the novel coronavirus to a 'Variant of Concern' (VoC), the question being asked is, can the variant escape already available vaccines?
B.1.617 has been reported from at least 21 countries and data suggests it is the prominent variant in parts of north India and Maharashtra.
FIT speaks with Prof Ravindra Gupta, a clinical microbiologist at the Cambridge Institute of Therapeutic Immunology and Infectious Disease at the University of Cambridge.
Prof Gupta's lab sequenced nine samples of the Indian variant, referred to colloquially as the 'Double Mutant' and more formally as B.1.617. The variant consists of two significant mutations E484Q and L452R.
He found that the variant did not significantly alter the response of the vaccines and vaccines will still offer protection from severe disease and hospitalisations.
How did you sequence B.1.617 in the lab and what were the prominent findings? How does the variant impact vaccines?
We were interested in seeing how B.1.617 is expanding in India, says Prof Gupta. "We wanted to examine the hype around the variant and if the two mutations could evade neutralising antibodies." One of the mutations, E484Q is similar to E484K found in South Africa and Brazil, but the worry was it would have a similar reaction to vaccines.
"We generated artificial viruses in the lab, which have spike protein on the surface, a well-validated system, and then we tested the ability of antibodies to block those viruses from entering the cell – in other words, what we call neutralisation," says Prof Gupta.
If the spike protein has mutated or changed, some of the antibodies form via vaccination will not be able to recognise the spike protein.
We used blood or serum from Pfizer’s mRNA vaccine, and I don’t expect there to be big differences between Pfizer and AstraZeneca’s vaccine, because they all use the same sequence of building blocks in the spike protein.Prof Ravindra Gupta
While L452R did increase the resistance to antibodies by 4-5 times, it was modest change. Prof Gupta says also sequenced E483Q and E484K mutations. And while E484K mutation (Brazil and South Africa mutation) showed a 10-fold resistance, E484Q had a more modest 5-6 fold increase.
But the more interesting finding was that when put together, the two mutations didn’t add up to produce a 10-fold resistance. It remained at 5- fold increase. So its important to highlight that this double-mutation is not really double the threat.
Prof Gupta says the vaccines will continue to protect against more severe disease and hospitalisations. Though the variant does appear to be more transmissible.
India’s other prominent vaccine is Covaxin. Do you expect Covaxin to react in a similar fashion to the Indian Variant?
"I would expect Covaxin to react in a similar way since it uses a virus that has a similar sequence in its spike protein as AstraZeneca and Pfizer vaccine," says Prof Gupta.
A study conducted by Indian Council of Medical Research, National Institute of Virology and Bharat Biotech, makers of India's indigenous Covaxin, indicates that the vaccine is effective against B.1.617.
In general it is in the right direction of reassurance, but we should remember that there are two significant mutations in the variant that potentially could generate a more infectious virus.Prof Ravindra Gupta
"The key thing to worry about is the amount of death and disease we are seeing in India, but the actual variant is not responsible for a majority of what we are seeing. It's an added problem of a lack of containment and transmission," adds Prof Gupta. He stresses on the fact that lockdowns and restrictions are well known ways of containing the spread.
How big is the risk of reinfections with the variant?
"In the UK, we've seen many people getting reinfected, some with more serious disease due to the Kent/UK variant. We know that vaccine responses in older individuals is poorer, so we will be seeing populations that are less responsive to vaccines or previous infections," says Prof Gupta. "Their immunity will not reach very high peaks and will drop off quicker, and therefore they'll be at risk of more severe disease and reinfections," he adds.
(This was first published on FIT and has been republished with permission.)
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