“If everyone is vaccinated, then maybe that’s not a big deal, because you’ve just got a cold going around,” Hodcroft said. “But if you’ve got a partially vaccinated population, that means you still have some susceptible people, where if a vaccinated person passes it on to a non-vaccinated person, they could still be in danger of being hospitalized or dying.”
The question of whether the vaccines might lose more of their power against the variant faster than they would against other SARS-2 iterations is also of concern. How long the protection elicited by any of the existing vaccines lasts against any version of the virus, remains questionable. Researchers would need to track vaccinated people and watch when their immunity wanes in order to gain insight.
Novavax and J&J results should serve signal those in the global scientific community — including vaccine makers and regulators — to prepare, in case the B.1.351 variant or some other form of SARS-2 is able to “escape” immune protection in ways the trial data do not yet show. Vaccines appeared to guard against severe disease from B.1.351 during the trial, but it is uncertain whether people will carry that protection for a long period.
What about the Moderna and Pfizer vaccines?
The clinical trials of the two vaccines authorized in the U.S. — the Moderna and Pfizer-BioNTech products — were completed before COVID variants of concern appeared. Consequently, there is no clinical data on how effective the shots are against B.1.351.
Scientists have studied lab experiments showing how well neutralizing antibodies taken from people who’ve been vaccinated fight off the variants. So far, the companies have reported drops in the antibodies’ potency against B.1.351 or select mutations in the variant, but the message from them and other scientists has been that the shots produce such sky-high levels of defense that they can withstand some loss of response without really changing how well they protect people.
But scientists caution that it’s difficult to determine what those lab experiments mean for the real world. The experiments only look at neutralizing antibodies, while the immune response includes other types of antibodies as well as fighters like T cells.
But the drop in neutralizing antibody power in the experiments, combined with the drop in efficacy in the Novavax and J&J trials, leads some experts to think that if the Moderna or Pfizer vaccines were put up against B.1.351 in trials, they might also see declines in efficacy.
Currently, B.1.351 accounts for just a fraction of global Covid-19 infections. But already, researchers are exploring ways to update vaccines to better target it or other variants that appear. Vaccine makers have announced they’re studying strain-specific boosters or next-generation vaccines that could target multiple variants, and regulators have said they’re considering how to approve modified vaccines without requiring the full package of trials that new products have to fulfill.
B.1.351 is not the only variant that researchers worry could evade the immune response. Another variant identified first in Brazil, called P.1 shares some of the same mutations. There is preliminary evidence that both variants can slip past the protection generated after an initial Covid-19 case and reinfect people more easily than other SARS-2 types.
It remains imperative to vaccinate as many people as quickly as possible with the shots that are available, experts stress. If anything, the variants add pressure to pick up the global pace of vaccinations. The shots protect people from Covid-19. And, if they can help drive down and decrease the likelihood that other potentially dangerous variants emerge.
“We need to vaccinate even faster and even more,” Andersen said. “The vaccines are still effective.”