There is now real evidence that at least one coronavirus variant seems to elude some of the power of Covid-19 vaccines. What, exactly, that means for the pandemic is still being examined. The vaccines may turn out to be less powerful against the variant, but they still appear to protect people from the worst outcomes, like hospitalization or death. The loss in the intended results against the B.1.351 variant in clinical trials suggests to some experts that the immunity the shots deliver may not last as long against that form of the coronavirus. It is indicated that the vaccines won’t be as powerful in combatting B.1.351 transmission, the way scientists hope the shots will be for other versions of the virus.
Experts say the disparate results could serve as a warning flag that the world needs to step up its current vaccination campaigns and expedite efforts to envision what Covid-19 vaccines 2.0 might look like.
“It’s a huge relief to know that the vaccines still seem to protect against hospitalization and deaths,” said Emma Hodcroft, a molecular epidemiologist at the University of Bern. “The No. 1 thing at the moment is to try and reduce in any way the cost that this virus charges us as it spreads through societies. But it’s definitely true the loss in efficacy, it raises some worrying questions.”
Positive results
Questions about vaccines revolve around the bottom line of whether they “work” or not against the different forms of the SARS-CoV-2 coronavirus. However that oversimplifies what clinical trials are measuring, what the vaccines might be able to do, and how much of this is a matter of degrees, rather than a definitive yes-or-no answer.
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The trials have generally been investigating whether the vaccines prevent symptomatic cases of Covid-19. But Covid-19 presents across a full spectrum, from asymptomatic infections to fatal ones, which is why some trials also include data specifically focused on the outcomes in which people are most interested: will it prevent severe disease and death.
In a way, the first clinical trial results from Moderna and the Pfizer and BioNTech team, which both showed the respective vaccines were 90% or more protective against symptomatic disease, spoiled us for what we could expect for immunizations still going through trials. The achievements went way beyond what experts had hoped Covid-19 vaccines could attack.
So when Johnson & Johnson reported last week that its vaccine was, on average, 66% efficacious at blocking moderate and severe disease — a figure that ticked up to 72% when just looking at U.S. participants — many researchers sought to remind people that this was a result worth celebrating. The vaccine was 85% effective against severe disease cases no matter the infectious variant, and all the deaths and hospitalizations in the trial occurred among people who got the placebo, not the vaccine.
“People look at 72% and say well that’s not as good as 90%, but the fact is, if you look at serious disease, it was extremely effective in preventing serious disease, including hospitalizations and deaths,” Anthony Fauci, the head of the National Institute of Allergy and Infectious Diseases, told reporters this week.
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Average results
Clinical trial data released last week for the J&J shot and another from Novavax showed the vaccines did not fare as well in South Africa, where the B.1.351 variant first emerged. The efficacy of the J&J shot against moderate or worse Covid-19 fell to 57% in South Africa, while Novavax reported its vaccine was 49% effective in South Africa at preventing symptomatic Covid-19.
Some experts said the results indicated the vaccines might be less powerful against the variant B.1.351 in other ways, too.
Clinical trials have not shown whether any of the existing vaccines can slow the spread of any version of SARS-2, but many experts think the shots will offer some help in that arena, whether because they prevent some infections entirely, or because they make people who still contract the virus less contagious for a shorter time, or some combination of factors.
