The BA.4 and BA.5 subvariants of the new coronavirus manage to evade the antibodies of people who have had a previous Covid-19 infection and those who have already received the booster dose of the vaccine, according to new data from researchers at the School of Medicine of Harvard.
However, vaccination against Covid-19 still provides substantial protection against severe forms of the disease, and immunization manufacturers are working on updating vaccines against the variants.
Levels of neutralizing antibodies that a previous infection or vaccination triggers are several times lower against Ômicron’s BA.4 and BA.5 subvariants, compared to the original strain of the novel coronavirus, according to new research published in the New England Journal. of Medicine on Wednesday (22).
“We observed 3-fold reductions in the levels of neutralizing antibodies against BA.4 and BA.5 compared to BA.1 and BA.2, which are already substantially lower than the original Covid-19 strains,” he told CNN The Doctor. Dan Barouch, author of the article and director of the medical center’s Virology and Vaccine Research Center.
“Our data suggest that these new subvariants are likely to be able to cause outbreaks of infections even in populations with high levels of immunity, either naturally or through vaccination,” Barouch said. “However, the vaccine should still provide substantial protection against severe symptoms.”
The newly published findings reinforce research findings by scientists at Columbia University. These experts recently discovered that the BA.4 and BA.5 subvariants are more likely to evade antibodies from fully vaccinated adults compared to other subvariants of Omicron.
The Columbia researchers say their results point to an increased risk of reinfection, even in people who have some prior immunity to the virus.
The US Centers for Disease Control and Prevention (CDC) estimates that 94.7% of the US population aged 16 and over have antibodies against the new coronavirus due to vaccination, infection, or both.
The BA.4 and BA.5 subvariants caused about 35% of new Covid-19 infections in the United States last week, up from 29% the previous week, according to data shared by the CDC.
The new strains, the fastest-spreading on record to date, are expected to dominate the transmission of Covid-19 in the US, UK and the rest of Europe in the coming weeks, according to the European Center for Disease Prevention and Control.
Ability for new mutations
In the New England Journal of Medicine article, among 27 research participants who received the booster dose of the Pfizer/BioNTech vaccine, levels of neutralizing antibodies against the new subvariants were much lower than those against the original strain of the novel coronavirus. .
Levels were lower by a factor of 6.4 against BA.1; by a factor of 7 against BA.2; by a factor of 14.1 against BA.2.12.1 and by a factor of 21 against BA.4 or BA.5, the researchers described.
In those with previous infection – most of whom had also been vaccinated – the researchers described levels of neutralizing antibodies that were lower by a factor of 6.4 against BA.1; by a factor of 5.8 against BA.2; by a factor of 9.6 against BA.2.12.1 and by a factor of 18.7 against BA.4 or BA.5.
“Our data suggest that Covid-19 still has the ability to mutate again, resulting in greater transmissibility and greater antibody escape,” Barouch said. “As pandemic restrictions are relaxed, it is important that we remain vigilant and continue to study new variants.”
A separate study, published in the journal Nature last week, found that Ômicron can develop mutations to ward off immunity brought on by a previous infection, which suggests that initial booster doses may not achieve broad-spectrum protection against new subvariants.
As for what all this means in the real world, Dr. Wesley Long, an experimental pathologist at Houston Methodist Hospital, told CNN that people should be aware that they can get sick again, even if they have had Covid-19 before.
Some vaccine manufacturers have been developing variant-specific vaccines to improve antibody responses.
“Reinfections will be unavoidable until we have new updated immunizers. But the good news is that we are in a much better situation than we were without vaccines,” she said. Pavitra Roychoudhury of the Department of Laboratory Medicine and Pathology at the University of Washington. “We expect the protections we have in place will mostly lead to mild infections.”
vaccine update
Moderna’s bivalent Covid-19 vaccine booster, called mRNA-1273.214, elicited “potent” immune responses against Ômicron’s BA.4 and BA.5 subvariants, the company said Wednesday.
Moderna said it is working to complete regulatory submissions in the coming weeks requesting to update the composition of its booster dose.
“Given the continued evolution of SARS-CoV-2, we are very encouraged that mRNA-1273.214, our main candidate for booster, has shown high levels of neutralization against subvariants BA.4 and BA.5, which pose an emerging threat to global public health,” said Stéphane Bancel, CEO of Moderna.
The U.S. regulatory agency’s Vaccines and Related Biologicals Advisory Committee will meet next week to discuss the composition of Covid-19 vaccines that can be used as a booster dose in the coming months.
Source: CNN Brasil
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