Does getting infected with ómicron result in immunity to the virus?
0:58
(CNN) --
The BA.4 and BA.5 subvariants of omicron appear to evade antibody responses both among people who have had a prior Covid-19 infection and among those who have been fully vaccinated and boosted, according to new reports. data from researchers at Beth Israel Deaconess Medical Center, Harvard Medical School.
However, vaccination against Covid-19 is expected to continue to provide substantial protection against severe disease, and vaccine makers are working on upgrading them to elicit a stronger immune response against variants.
Levels of neutralizing antibodies generated by previous infection or vaccinations are several times lower against the BA.4 and BA.5 subvariants compared to the original coronavirus, according to new research published Wednesday in the New England Journal of Medicine.
"We observed 3-fold reductions in infection- and vaccination-induced neutralizing antibody titers against BA.4 and BA.5 compared to BA.1 and BA.2, which are already substantially lower than the original COVID-19 variants." -19," Dr. Dan Barouch, the paper's author and director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center in Boston, wrote in an email to CNN.
Being infected with omicron does not mean complete protection against the other subvariants of the same family, according to Chinese researchers
"Our data suggest that these new omicron subvariants will likely be able to trigger waves of infections in populations with high levels of immunity to the vaccine, as well as natural immunity to BA.1 and BA.2," Barouch wrote.
"However, vaccine immunity is likely to continue to provide substantial protection against severe BA.4 and BA.5 disease."
The newly published results echo other research by scientists at Columbia University.
advertising
Researchers 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 post-vaccination Covid infections. -19.
The authors of that separate study 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 older have antibodies against the coronavirus that causes covid-19. 19 through vaccination, infection, or both.
The BA.4 and BA.5 viruses are estimated to have caused 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 on Tuesday.
The BA.4 and BA.5 variants are the fastest spreading to date, and are expected to dominate COVID-19 transmission 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 capacity to mutate more"
In the New England Journal of Medicine article, among 27 research participants who had been vaccinated and boosted with the Pfizer/BioNTech COVID-19 vaccine, researchers found that two weeks after the booster dose, levels of neutralizing antibodies against the omicron subvariants were much lower than the response against the original coronavirus.
Neutralizing antibody levels were lower by a factor of 6.4 against BA.1;
by a factor of 7 against the 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 the 27 participants who had previously been infected with the BA.1 or BA.2 subvariants a mean 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 against BA.2.12.1 and by a factor of 18.7 against BA.4 or BA.5.
More research is needed to determine what exactly neutralizing antibody levels mean for vaccine efficacy and whether similar results would emerge among a larger group of participants.
Summer arrives in Europe with a new wave of covid-19
"Our data suggest that COVID-19 still has the ability to mutate further, resulting in higher transmissibility and greater antibody evasion," 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."
A separate study, published in the journal Nature last week, found that the omicron variant can evolve with mutations to evade immunity triggered by having a previous BA.1 infection, suggesting that vaccine boosters based on the subvariant BA.1 may not achieve broad-spectrum protection against new omicron subvariants such as BA.4 and BA.5.
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 already had COVID-19. before.
"I think I'm a little concerned that people who have recently gotten sick 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 who got sick from a BA.2 variant in recent months," he said.
Some vaccine manufacturers have been developing variant-specific vaccines to improve antibody responses against coronavirus variants and subvariants of concern.
The new variants will keep covid-19 in circulation throughout the boreal summer
"Re-infections are going to be pretty unavoidable until we have vaccines or widespread mandates that prevent cases from rising again. But the good news is that we are, I think, much better off than we were without vaccines," Pavitra said. Roychoudhury, an acting instructor 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 currently have will lead to mostly mild infection."
Efforts underway to update covid-19 vaccines
Moderna's bivalent COVID-19 booster vaccine, dubbed mRNA-1273.214, elicited a "potent" immune response against omicron's BA.4 and BA.5 subvariants, the company reported Wednesday.
This bivalent booster vaccine 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 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 neutralization titers against subvariants BA.4 and BA.5, which represent a emerging threat to global public health," Moderna CEO Stéphane Bancel said in Wednesday's announcement.
SARS-CoV-2 is the coronavirus that causes covid-19.
Moderna's First Bivalent COVID-19 Booster Vaccine Induces Greater Antibody Response Than Original Booster, Company Says
"We will present this data to regulators urgently and are preparing to supply our next-generation bivalent booster starting in August, anticipating a potential increase in SARS-CoV-2 infections due to omicron subvariants in early fall." Bancel said.
The US Food and Drug Administration's Vaccines and Related Biologicals Advisory Committee will meet next week to discuss the composition of Covid-19 vaccines that could be used as boosters this fall.
Data Moderna released Wednesday, which has not been published in a peer-reviewed journal, showed that one month after administration of a 50 microgram dose of the mRNA-1273,214 vaccine in people who had been vaccinated and boosted , the vaccine elicited "strong" 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 subset of those without a history of prior infection.
These neutralizing antibody levels were approximately 3-fold lower than previously reported neutralizing levels against BA.1, Moderna said.
These findings add to data that Moderna previously published earlier this month showing that the 50-microgram dose of the bivalent booster elicited a stronger antibody response against omicron than Moderna's original vaccine.
in a statement published by the UK Science Media Center on Wednesday.
She did not participate in the work of Moderna.
"The bivalent vaccine has previously been 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.
immunomicron