However, vaccination against Covid-19 is still expected to provide substantial protection against serious illness, and vaccine makers are working on updated shots that could elicit a stronger immune response against variants.
“We observed 3-fold reductions in infection- and vaccination-induced neutralizing antibody titers against BA4 and BA5 compared to BA1 and BA2, which are already substantially lower than the original COVID-19 variants,” 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, in an email to CNN.
“Our data suggest that these new Omicron subvariants will likely be able to cause surges in infections in populations with high levels of vaccine immunity, as well as natural BA1 and BA2 immunity,” Barouch wrote. “However, vaccine immunity is likely to still provide substantial protection against severe disease with BA4 and BA5.”
The newly published findings echo separate research by scientists at Columbia University.
They recently found that 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 novel covid-19 infections in the vaccine.
BA.4 and BA.5 are the fastest-spreading variants reported to date, and are expected to dominate transmission of Covid-19 in the United States, the United Kingdom and the rest of Europe in the coming weeks, according to the European Center for 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, antibody levels Neutralizing responses against Omicron subvariants were much lower than responses against the original coronavirus.
Neutralizing antibody levels were lower by a factor of 6.4 versus 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 been previously infected with the BA.1 or BA.2 subvariants a median of 29 days earlier, the researchers found similar results.
In those with prior 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 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 neutralizing antibody levels mean for vaccine effectiveness and whether similar findings would emerge among a larger group of participants.
“Our data suggest that COVID-19 still has the ability to mutate further, resulting in increased transmissibility and increased antibody escape,” Barouch wrote in the email. “As pandemic restrictions are lifted, it is important that we remain vigilant and continue to study new variants and sub-variants as they emerge.”
As for what this all means in the real world, Dr. Wesley Long, an experimental pathologist at Houston Methodist Hospital, told CNN that people need to be aware that they could get sick again, even if they’ve had covid-19. 19 before.
“I think I’m a little concerned that people who have had it recently might have a false sense of security with BA.4 and BA.5 on the rise, because we’ve seen some cases of reinfection and I’ve seen some cases of reinfection with people that they had a BA.2 variant in the last few months,” he said.
Some vaccine manufacturers have been developing variant-specific vaccines to enhance antibody responses against variants and subvariants of coronaviruses of interest.
“Re-infections are going to be pretty inevitable until we have vaccines or widespread mandates that prevent cases from rising again. But the good news is that we are, I think, in a much better place than without vaccines,” he said. Pavitra Roychoudhury, an interim professor in the Department of Laboratory Medicine and Pathology at the University of Washington, who was not involved in the New England Journal of Medicine article.
“There is so much of this virus out there that it seems inevitable,” he said of Covid-19 infections. “Hopefully the protections we have in place will lead to a mostly mild infection.”
Efforts underway to update vaccines against Covid-19
This bivalent booster vaccine candidate contains components of both Moderna’s original Covid-19 vaccine and a vaccine that targets the Omicron variant. The company said it is working to complete regulatory filings in the coming weeks requesting to update the composition of its booster vaccine to be mRNA-1273.214.
“Given the continued evolution of SARS-CoV-2, we are very encouraged that mRNA-1273.214, our top booster candidate for the fall, has shown high neutralizing titers against subvariants BA.4 and BA.5, which represent an emergency. threat to global public health,” Stéphane Bancel, CEO of Moderna, said in Wednesday’s announcement. SARS-CoV-2 is the coronavirus that causes Covid-19.
“We will present this data to regulators urgently and are preparing to supply 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.” Bancel said.
Data Moderna released Wednesday, which has not been published in a peer-reviewed journal, showed that one month after a 50-microgram dose of the mRNA-1273.214 vaccine was administered to people who had been vaccinated and boosted, the The vaccine elicited “potent” neutralizing antibody responses against BA.4 and BA.5, increasing levels 5.4-fold in all participants, regardless of whether they had prior Covid-19 infection, and 6.3-fold in the subgroup of those with no history of prior infection.These neutralizing antibody levels were about 3 times lower than previously reported neutralizing levels against BA.1, Moderna said.
These findings add to data Moderna published earlier this month showing that the 50-microgram dose of the bivalent booster elicited a stronger antibody response against Omicron than the original Moderna vaccine.
“The bivalent vaccine was previously reported to be well tolerated with temporary ‘reactogenic’ effects similar to those following the univalent booster injection, 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 COVID infection landscape, it certainly makes sense to consider using this new bivalent vaccine, if it becomes available.”
CNN’s Brenda Goodman contributed to this report.