However, the Covid-19 vaccination should still provide substantial protection against serious illnesses, and vaccine makers are working on updated vaccines that could trigger a stronger immune response against the variants.
“We observed 3-fold reductions in vaccination and infection-induced neutralizing antibody titers against BA4 and BA5 compared to BA1 and BA2, which are already significantly lower than the original COVID-19 variants,” said said Dr. Dan Barouch, author of the article. and director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center in Boston, wrote in an email to CNN.
“Our data suggest that these new Omicron subvariants are likely to lead to outbreaks of infections in populations with high levels of vaccine immunity as well as natural BA1 and BA2 immunity,” Barouch wrote. “However, it is likely that vaccine immunity will still provide substantial protection against severe disease with BA4 and BA5.”
The newly published findings echo separate research conducted by scientists at Columbia University.
They recently found that the BA.4 and BA.5 viruses were more likely to evade antibodies from the blood of fully vaccinated and boosted adults compared to other Omicron subvariants, increasing the risk of Covid-19 infections. 19 revolutionaries.
BA.4 and BA.5 are the fastest-spreading variants reported to date, and they are expected to dominate Covid-19 transmission in the US, UK and the rest of Europe over the next few months. coming weeks, according to the European Research Centre. Disease prevention and control.
“COVID-19 still has the ability to mutate further”
In the New England Journal of Medicine article, among 27 research participants who had been vaccinated and boosted with the Pfizer/BioNTech coronavirus vaccine, researchers found that two weeks after the booster dose, levels of neutralizing antibodies against Omicron subvariants were much lower than response against the original coronavirus.
Levels of neutralizing antibodies were 6.4-fold lower 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.
Among 27 participants who had previously been infected with the BA.1 or BA.2 subvariants a median of 29 days earlier, the researchers found similar results.
In those who had already been infected – most of whom had also been vaccinated – the researchers described 6.4-fold lower levels of neutralizing antibodies against BA.1; by a factor of 5.8 against BA.2; by a factor of 9.6 compared to BA.2.12.1 and by a factor of 18.7 compared to BA.4 or BA.5.
Further research is needed to determine what exactly neutralizing antibody levels mean for vaccine effectiveness and whether similar findings would emerge among a larger group of participants.
“Our data suggests that COVID-19 still has the ability to mutate further, leading to increased transmissibility and increased antibody leakage,” Barouch wrote in the email. “As pandemic restrictions are lifted, it is important that we remain vigilant and continue to investigate new variants and subvariants as they emerge.”
As for what all of 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 could get sick again, even if they’ve had Covid before. -19.
“I think I’m a bit concerned that people who have had it may have a false sense of security recently with the increase in BA.4 and BA.5, because we’ve seen cases of re-infection and I “I’ve seen a few cases of reinfection with people who had a BA.2 variant in the past few months,” he said.
Some vaccine makers have developed variant-specific vaccines to improve antibody responses against coronavirus variants and subvariants of concern.
“Reinfections are going to be pretty inevitable until we have vaccines or widespread mandates that will stop cases from rising again. But the good news is that we are, I think, in a much better situation than we are. We were without the vaccines,” said Pavitra Roychoudhury, acting professor in the Department of Laboratory Medicine and Pathology at the University of Washington, who did not participate in the New England Journal of Medicine article.
“There is so much of this virus out there that it seems inevitable,” she said of Covid-19 infections. “Hopefully the safeguards we have in place will lead to mostly mild infection.”
Ongoing efforts to update Covid-19 vaccines
This bivalent booster vaccine candidate contains components of Moderna’s original Covid-19 vaccine and a vaccine that targets the Omicron variant. The company said it is working to complete regulatory submissions in the coming weeks asking to update the composition of its booster vaccine to be mRNA-1273.214.
“As SARS-CoV-2 continues to evolve, we are very encouraged that mRNA-1273.214, our lead knockdown candidate, showed high neutralizing titers against BA subvariants. 4 and BA.5, which represent an emerging threat to global public health,” said Stéphane Bancel, chief executive of Moderna, in Wednesday’s announcement. SARS-CoV-2 is the coronavirus that causes Covid-19 .
“We will submit this data to regulators urgently and prepare to deliver our next-generation bivalent booster starting in August, ahead of a potential increase in SARS-CoV-2 infections due to Omicron subvariants in early fall,” Bancel said.
‘potent’ neutralizing antibody responses against BA.4 and BA.5, increasing levels by 5.4-fold in all participants whether or not they had previous Covid-19 infection and by 6.3-fold in the subset of those with no history of previous infection. These neutralizing antibody levels were about 3 times lower than previously reported neutralizing levels against BA.1, Moderna said.
These results add to data previously published by Moderna earlier this month, showing that the 50 microgram dose of the bivalent booster generated a stronger antibody response against Omicron than the original Moderna vaccine.
“The bivalent vaccine has been previously reported to be well tolerated with similar temporary ‘reactogenic’ effects to those following the univalent booster shot, so we can anticipate that this new mixed vaccine should be well tolerated,” Ward said. in part. “As we head into the fall with omicron variants dominating the landscape of covid infections, it certainly makes sense to consider the use of this new bivalent vaccine, if it becomes available.”
CNN’s Brenda Goodman contributed to this report.
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