Thursday, November 10, 2022
COVID
The Latest COVID-19 Variants Can Evade Vaccine Protection, According to New Data
New lab data suggest that vaccines and prior infections may not offer enough protection against several new COVID-19 variants cropping up in the U.S. and around the world.
Dr. David Ho, director of Columbia University’s Aaron Diamond AIDS Research Center (ADARC), and his team reported the results from a set of studies at an ADARC symposium. They showed how well some of the latest variants—BQ.1, BQ.1.1, XBB, and XBB.1, which were all derived from Omicron—are evading both vaccine-derived and infection-derived immunity.
These new variants all have mutations in the region that binds to cells and infects them, which means that they’re highly transmissible, as prior Omicron variants were. BQ.1 is growing steadily in France, according to the public database of SARS-CoV-2 variants GISAID. By mid-November, European health officials expect the variant to account for 50% of cases in Europe, and to become the dominant strain in that region by early 2023. XBB is growing quickly in Singapore and India. Both variants have spawned new strains that have each picked up an additional mutation to create BQ.1.1 and XBB.1. As of early November, BQ.1 and BQ.1.1, combined, now make up about 35% of new cases in the U.S.
Other studies have found similar drops in antibody protection against BQ.1 among vaccinated people. But Ho’s group conducted what is likely the most comprehensive look to date at BQ.1, BQ.1.1, XBB, and XBB.1, and how existing immunity—from the original mRNA vaccines, the new Omicron boosters, and natural infections—stands up to them. Scientists took blood sera from 88 people in five groups (below) and exposed it to the four variants in the lab. Here’s what they found:
- Fully vaccinated and once-boosted people (three total shots of the original mRNA vaccines) had 37- and 55-fold lower neutralization against BQ.1 and BQ.1.1, respectively, than they did against the original SARS-CoV-2 virus, and about 70-fold lower neutralization against XBB and XBB.1.
- Fully vaccinated and twice-boosted people (four total shots of the original mRNA vaccines) had 43- and 81-fold lower neutralization against BQ.1 and BQ.1.1, respectively, than they did against the original virus, and 145- and 155-fold lower neutralization against XBB and XBB.1, respectively.
- Fully vaccinated and twice-boosted people (three shots of the original vaccine plus one Omicron booster) had 24- and 41-fold lower neutralization against BQ.1 and BQ.1.1, respectively, than they did against the original virus, and 66- and 85-fold lower neutralization against XBB and XBB.1, respectively.
- Fully vaccinated people who had received the original booster and who had been infected with BA.2 had 20- and 29-fold lower neutralization against BQ.1 and BQ.1.1, respectively, than they did against the original virus, and 103- and 135-fold lower neutralization against XBB and XBB.1, respectively.
- Fully vaccinated people who had received the original booster and who had been infected with BA.4 or BA.5 had 13- and 31-fold lower neutralization against BQ.1 and BQ.1.1, respectively, than they did against the original virus, and 86- and 96-fold lower neutralization against XBB and XBB.1, respectively.
The results show that people who had been infected with BA.2, BA.4, or BA.5 generally experienced the smallest drop in neutralizing antibody levels against against BQ.1 and BQ.1.1. But people who had three doses of the original vaccine and one Omicron booster produced only slightly better neutralizing antibody protection against XBB and XBB.1 than those who received three doses of the original vaccine. Public-health experts say that while vaccines may wane in efficacy against newer variants, they continue to protect people from severe COVID-19. There is early evidence that vaccine-induced immunity may also produce a broader range of virus-fighting antibodies over time.
Still, these results are a reminder that vaccines and drug treatments need to evolve with the virus. “These new variants are extremely good at evading our antibodies and are very likely to compromise the efficacy of our vaccines,” says Ho. They may also dodge the available antibody-based treatments for COVID-19, he says. The National Institutes of Health’s COVID-19 Treatment Guidelines currently only include one monoclonal antibody therapy, bebtelovimab, because the virus has evaded all of the previously authorized antibody treatments. But in an October update, NIH scientists acknowledged that the “subvariants BQ.1 and BQ.1.1 are likely to be resistant to bebtelovimab.” The drug is therefore only recommended if people either can’t take the antiviral drugs Paxlovid or remdesivir, or if these medications aren’t available. The virus can evade these treatments as well, but they remain the first line of defense against severe SARS-CoV-2.
The good news is that in places where these variants are spreading, they do not seem to be linked to more severe COVID-19 disease—measured by hospitalizations and deaths—than other Omicron iterations. Still, public-health experts say a spike in infections could still strain health resources, especially as other respiratory infections, including influenza and RSV, also gain momentum. The combination of several circulating infectious diseases could mean more illness overall, and, in turn, more people who might experience severe disease and require intensive medical care.
The rise of BQ.1, BQ.1.1, XBB, and XBB.1 points to the fact that when it comes to immunity, the virus may always be one step ahead, especially with respect to vaccines. “I would start to make these vaccines, and start to test them in animals,” says Ho. Even if those efforts began now, it’s possible they may still lag behind the virus and the new mutations it continues to gain. That’s why researchers are working on developing vaccines that would be more universally applicable to a range of different coronaviruses, which could shorten the amount of time it takes to build up a vaccinated population’s immunity.
Source: Time
