Delta variant unable to evade antibodies generated by vaccination: Study

A new study revealed that the Delta variant of the SARS-CoV-2 virus, which causes COVID-19, is unable to evade the antibodies generated by vaccination. The findings explained why vaccinated people have largely escaped the worst of the Delta surge.

The study was done by researchers at the Washington University School of Medicine in the US. They analysed a panel of antibodies that were generated by people in response to the Pfizer COVID-19 vaccine and found that Delta was unable to evade all but one of the antibodies they tested.

The other variants, such as Beta, avoided recognition and neutralisation by several of the antibodies.

In another study, findings indicated that both natural infection and vaccination elicit lasting antibody production. This study was done by Ali Ellebedy, an associate professor at Washington University.

However, the researchers maintained that the length of the antibody response is only one aspect of protection.

The researchers said that an ideal antibody response includes a diverse set of antibodies. It has the flexibility to recognise many slightly different variants of the virus.

“The fact that Delta has outcompeted other variants does not mean that it’s more resistant to our antibodies compared to other variants,” said co-senior author Jacco Boon, an associate professor at Washington University.

“A variant that replicates better is likely to spread faster, independent of its ability to evade our immune response. So Delta is surging, yes, but there’s no evidence that it is better at overcoming vaccine-induced immunity compared to other variants,” Boon added.

This is how the study was done: The scientists grew the cells in the laboratory. From them, they obtained a set of 13 antibodies that target the original strain which began circulating last year.

The antibodies were tested against four variants of concern: Alpha, Beta, Gamma and Delta.

Twelve of the 13 recognised Alpha and Delta, eight recognised all four variants, and one failed to recognise any of the four variants.

Scientists said that this was done by the antibody’s ability to block the virus from infecting and killing cells in a dish.

The researchers found that five of the 13 antibodies neutralised the original strain.

“In face of vaccination, Delta is relatively a wimpy virus. If we had a variant that was more resistant like Beta but spread as easily as Delta, we would be in more trouble,” Ellebedy said.

The antibody that neutralised all four variants of concern — as well as three additional variants tested separately — was called 2C08, the researchers said.