The Pfizer and Moderna Covid-19 vaccines remain highly effective against two coronavirus variants first identified in India, a laboratory-based study carried out by US scientists shows.
According to an AFP report from Washington, the study was conducted by the NYU Grossman School of Medicine and NYU Langone Center and is considered preliminary because it has not yet been published in a peer-reviewed journal.
"What we found is that the vaccine's antibodies are a little bit weaker against the variants, but not enough that we think it would have much of an effect on the protective ability of the vaccines," senior author Nathaniel "Ned" Landau told AFP on Monday.
"Our results lend confidence that current vaccines will provide protection against variants identified to date," the team concluded.
However, they do not preclude the possibility that newer variants that are more resistant to vaccines will emerge — highlighting the importance of widespread vaccination at the global level.
The researchers took blood from people who were vaccinated with either of the two shots which have been given to more than 150 million Americans.
These samples were exposed in a lab to engineered pseudovirus particles that contained mutations in the "spike" region of the coronavirus, which were particular to either the B.1.617 or B.1.618 variants, first found in India.
Finally, that mixture was exposed to lab-grown cells, to see how many would become infected.
Overall, for B.1.617 they found an almost four-fold reduction in the amount of neutralizing antibodies — Y-shaped proteins the immune system creates to stop pathogens from invading cells. For B.1.618, the reduction was around three-fold.
"In other words, some of the antibodies now don't work anymore against the variants, but you still have a lot of antibodies that do work against the variants," said Landau.
However, the overall levels remain well above those found in samples taken from people who recovered from Covid infections and therefore will provide sufficient protection against the disease, the scientists said.
But this kind of lab investigation cannot predict what the real world efficacy might look like — that will have to be investigated through other studies.
