As UK lists Covid-19 Delta AY.2.4 as Variant Under Investigation, how are vaccine companies preparing for escape mutations?

Coronavirus variants: Since the coronavirus vaccines began rolling out, there has been discussion around mutations and strains that might be able to escape from the vaccine-generated immune response. To this end, booster shots and updated formulae have been discussed to some length among experts. However, since no new strains that can escape the immune response have yet been spotted, there has not been much headway in this direction. Now though, according to a report by news agency PTI, a new mutation of the Delta variant – Delta AY.4.2 – has been classified as Variant Under Investigation by the UK because of its high growth rate.

The variant had been dubbed as Delta Plus by the UK Health Security Agency (UKHSA) and it is now called the VUI-21OCT-01. In recent days, the variant has been under close scrutiny after the health authorities found evidence indicating a faster spread of the variant as compared to the dominant Delta variant. Though the evidence is still emerging, at this stage, it does not look like the Delta AY.4.2 is leading to more severe cases of infection or is rendering vaccines less effective.

Meanwhile, Nature reported that over the past three months, Pfizer, AstraZeneca and Moderna have all been running dress rehearsals and are practicing on known variants of the SARS-CoV-2. This means that all the three companies are updating their vaccines so that they can match the Beta and Delta variants of the virus, among others, and conducting clinical studies around this. They are also tuning internal workflows to this end, and are also in talks with regulators for smooth coordination. By this, they are hoping to tie up any loose ends, so that in case any Coronavirus variant does end up escaping the immune response generated by the Covid-19 vaccine, they can move fast and take action accordingly.

So far, the first generation of Covid-19 vaccines that have been released by the three companies are holding up strong against the known variants of the virus, including Delta, and are able to prevent cases of severe infection and hospitalisation. There is no need, as per them, to create a new, more effective vaccine at this point of time, and Pfizer and Moderna are confident that if any mutation does emerge, they would be able to design and synthesize an initial prototype shot within a few days, with AstraZeneca following close behind.

However, even if they were to develop vaccines quickly, running tests on humans would take time, and therefore, these companies are conducting dry runs so that things can go smoothly if and when such a vaccine is needed.