IIn recent months, as the global COVID-19 pandemic rages on, new varieties of SARS-CoV-2 have raised concerns about whether existing vaccines against the evolving virus are working as well as clinical trials. Three preprints published on bioRxiv This question was shed light on January 19 when it was found that serum from vaccinated individuals could neutralize a virus with some of the same mutations as a now widespread variant, B.1.1.7, but strains that mimic another were less able to neutralize effectively neutralized variant known as 501Y.V2.
One study looked at the effects of the 501Y.V2 variant found in South Africa using serum samples from 44 people with COVID-19. When these sera were exposed to the variant that has multiple mutations in its spike protein, 48 percent were unable to neutralize the virus.
“The data suggest that protection against previous infection with COVID-19 is less if you are re-infected with the South African variant,” said Liam Smeeth, an epidemiologist at the London School of Hygiene and Tropical Medicine, who was not involved in the study tells Reuters. “The data also suggest that existing vaccines against the South African variant may be less effective.”
In another study, serum samples from 16 people who had received the Pfizer vaccine were exposed to a virus with 10 mutations found in the spike protein of B.1.1.7, often referred to as the UK variant. The synthesized pseudovirus was easily neutralized by antibodies in the samples, which kept hopes for the effectiveness of the vaccine for this variant high.
The third study used serum samples from 20 people who had received either the Moderna or Pfizer / BioNTech vaccine to examine how the vaccine-induced immunity withstands certain mutations that affect the spike protein. Although antibodies to SARS-CoV-2 decrease over time after infection, B cells retain the ability to target spike proteins and receptor binding domains that are part of the spike that allows the virus to attach itself to infection To bind cells. The effectiveness of the serum against the pseudoviruses carrying the mutations was reduced compared to those with the dominant SARS-CoV-2 spike protein, and the samples neutralized the virus threat with a one to three-fold increase in antibodies. However, the small pool of samples lacks age and race differences, which are two key factors in COVID-19 results, Drew Weissman, an infectious disease expert who worked on vaccine development, told the Associated Press.
According to Oxford University biologist James Naismith, who was not involved in the study, neutralization is not the only marker to measure a successful immune response.
“The real human immune response is more than a serum-based neutralization,” says Naismith The guard. “Of course, we would prefer neutralization had taken place, but that doesn’t mean the new virus will infect, make sick, and spread from those who were already infected with the original strain.”
While the data suggests that the vaccines may not provide the same level of protection as clinical trials, they are still highly effective, University of Pennsylvania immunologist E. John Wherry, who was not involved in the research, told the Associated Press. “We don’t want people to think that the current vaccine is already out of date. That’s absolutely not true, ”he explains. “There is still immunity here. . . a good level of protection. ”
However, vaccine doctor Gregory Poland from Mayo Clinic, who did not participate in the studies, explains to the AP that relying solely on vaccines to curb the spread of COVID-19 is a breeze, and that more on that most basic level needs to be done. like social distancing and wearing masks. “We shoot ourselves in the foot by allowing this virus to pass unchecked,” he says.
Correction (Jan 22): An earlier version of the article incorrectly stated that the subjects in the first study mentioned had been vaccinated and the type of variant used in testing. We’ve also moved Drew Weissman’s quote to stand next to the study he was commenting on. The scientist regrets the mistakes.