Covid: Omicron subvariants BA.4 and BA.5 escape antibodies from vaccinations and previous infections, studies suggest

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.

The authors of this separate study say their results suggest a higher risk of reinfection, even in people who previously had some immunity to the virus. The US Centers for Disease Control and Prevention estimates that 94.7% of the US population ages 16 and older have antibodies to the coronavirus, which causes Covid-19 through vaccination, infection, or both.
BA.4 and BA.5 caused an estimated 35% of new Covid-19 infections in the United States over the past week, up from 29% the week before, according to data released on Tuesday by the US Centers for Disease Control and Prevention.

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.”

A separate study published last week in the journal Nature found that Omicron may evolve mutations to evade immunity induced by previous BA.1 infection, suggesting vaccine boosters based BA.1 may not achieve broadband protection against new Omicron sub-variants such as BA.4 and BA.5.
How well does our immunity hold up against Covid-19?

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

Moderna’s bivalent Covid-19 vaccine booster, dubbed mRNA-1273.214, elicited a “strong” immune response against Omicron subvariants BA.4 and BA.5, the company announced on Wednesday.
The search for longer-lasting 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 ship our next-generation bivalent booster starting in August ahead of a potential surge in SARS-CoV-2 infections due to Omicron subvariants in early fall,” said Bancel .

The U.S. Food and Drug Administration’s Vaccines and Related Biologicals Advisory Committee is meeting next week to discuss the composition of Covid-19 vaccines that could be used as a booster this fall.
According to Moderna, the updated Covid-19 vaccine booster shows a stronger antibody response against Omicron

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.

Moderna’s data suggest that “bivalent booster vaccination may provide greater protection against Omicron strains BA.4 and BA.5 than re-administration of the original vaccine to increase protection in the whole population. Although the information is based on antibody levels, the companies comment on similar levels of antibodies protecting against clinical disease caused by other strains is the first hint of an emerging “immune correlate” of protection, although it is hoped that this ongoing study will also Clinical disease rates as well as antibody responses assessed,” Penny Ward, an independent pharmaceutical doctor and visiting professor of pharmaceutical medicine at King’s College London, said in a statement released by Britain’s Science Media Center on Wednesday. She was not involved in Moderna’s work.

“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.