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However, the Covid-19 vaccine is still expected to offer significant protection against serious diseases and vaccine manufacturers are working on updated vaccinations that could elicit a stronger immune response against the variants.
“We observed a 3-fold reduction in neutralizing antibody titers induced by vaccination and infection against BA4 and BA5 compared to BA1 and BA2, which are already significantly lower than the original COVID-19 variants,” Dr. Dan Barouch, an author of the publication 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 an increase in infections in populations with high immunity to vaccination as well as natural BA1 and BA2 immunity,” Barouch wrote. “However, it is likely that vaccine immunity still provides significant protection against severe disease with BA4 and BA5.”
The newly published results reflect separate research by scientists at Columbia University.
They recently found that the BA.4 and BA.5 viruses were more likely to escape antibodies from the blood of fully vaccinated and boosted adults compared to other omicron subvariants, increasing the risk of Covid-19 infections from the vaccine breakthrough elevated.
BA.4 and BA.5 are the fastest spreading variants to date and are expected to dominate Covid-19 transmission in the United States, the United Kingdom and the rest of Europe within the next few weeks, according to the European Center for Disease Prevention and Control.
“COVID-19 still has the ability to continue mutating”
In the New England Journal of Medicine article, the researchers found that among 27 research participants who had been vaccinated and boosted with the Pfizer/BioNTech coronavirus vaccine, two weeks after the booster dose, levels of neutralizing antibodies against Omicron subvariants were much lower than the response against the original coronavirus.
The neutralizing antibody levels were 6.4 times lower against BA.1; by a factor of 7 compared to BA.2; by a factor of 14.1 versus BA.2.12.1 and by a factor of 21 versus BA.4 or BA.5, the researchers described.
The researchers found similar results among 27 participants who had previously been infected with subvariant BA.1 or BA.2 a median of 29 days prior.
In previously infected people – most of whom had also been vaccinated – the researchers described neutralizing antibody levels that were 6.4 times lower against BA.1; by a factor of 5.8 compared to 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.
More research is needed to determine what exactly the neutralizing antibody levels mean for the vaccine’s effectiveness and whether similar results would occur in a larger group of participants.
“Our data suggests that COVID-19 still has the ability to continue mutating, resulting in increased transmissibility and antibody leakage,” Barouch wrote in the email. “As pandemic restrictions lift, it is important that we remain vigilant and investigate new variants and subvariants as they emerge.”
As for what it all 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 previously had Covid-19.
“I think I’m a bit concerned that people who have had it might have a false sense of security with BA.4 and BA.5 on the rise lately because we’ve seen some cases of reinfection and I’ve seen some I’ve seen cases of reinfection in people who have had a BA.2 variant in the past few months,” he said.
Some vaccine manufacturers have developed variant-specific vaccines to improve antibody responses against coronavirus variants and subvariants of concern.
“Reinfections will be pretty much inevitable until we have vaccines or widespread mandates that prevent cases from recurring. But the good news is that I think we’re in a much better place than we were without the vaccines,” said Pavitra Roychoudhury, an acting associate in the University of Washington’s Department of Laboratory Medicine and Pathology, who did not contribute to the New England Journal article of Medicine was involved.
“There is so much of this virus out there that it seems inevitable,” she said of Covid-19 infections. “Hopefully the protective measures we have taken will result in a mostly mild infection.”
Efforts are underway to update the Covid-19 vaccines
This bivalent booster vaccine candidate contains components of both Moderna’s original Covid-19 vaccine and a vaccine targeting the Omicron variant. The company said it is working to complete regulatory filings requesting to update the composition of its booster vaccine to mRNA-1273.214 in the coming weeks.
“Given the continued evolution of SARS-CoV-2, we are very encouraged that mRNA-1273.214, our lead fall booster candidate, has demonstrated high neutralizing titers against subvariants BA.4 and BA.5, which pose an emerging threat to the global public health,” Moderna Chief Executive Officer Stéphane Bancel said in Wednesday’s announcement. SARS-CoV-2 is the coronavirus that causes Covid-19.
“We will urgently submit this data to regulatory authorities and prepare to deliver our next-generation bivalent booster starting in August, ahead of a possible early fall surge in SARS-CoV-2 infections due to Omicron subvariants,” said Bancel.
The data, which Moderna released on Wednesday and which were not published in a peer-reviewed journal, showed one month after the administration of a 50-microgram dose of the mRNA-1273.214 vaccine to people who had been vaccinated and boosted , which evoked vaccine. potent” neutralizing antibody responses against BA.4 and BA.5, increasing levels by 5.4-fold in all participants regardless of whether they had prior Covid-19 infection, and by 6.3-fold fold in the subgroup of those with no prior history of infection.These levels of neutralizing antibodies were about three times lower than previously reported neutralizing levels against BA.1, Moderna said.
These results add to data Moderna released earlier this month and show that the 50 microgram dose of the bivalent booster elicited a stronger antibody response to Omicron than the original Moderna vaccine.
“It has previously been reported that the bivalent vaccine is well tolerated, with transient ‘reactogenic’ effects similar to those seen after the univalent booster dose, so we can assume that this new mixed vaccine should be well tolerated,” Ward said in part. “As we head into the fall and Omicron variants dominate the Covid infection landscape, it certainly makes sense to consider using this new bivalent vaccine if available.”
CNN’s Brenda Goodman contributed to this report.
