SARS-CoV-2 Mutation and Vaccine Efficacy

SARS-CoV-2 Mutation and Vaccine Efficacy

In a January 25 piece in the New York Times, “As Virus Grows Stealthier, Vaccine Makers Reconsider Battle Plans,” they posit that the Moderna and Pfizer-BioNTech products are “slightly less effective” against the South African strain of COVID-19 and that the drug makers are revising plans to deal with this issue. For precaution, Moderna is developing a “new form” of the vaccine that might be used as a, “booster shot against the variant in South Africa.” Moderna’s chief medical officer Dr. Tal Zaks said, “We’re doing it today to be ahead of the curve, should we need to—-I think of it as an insurance policy.” The firm is also looking at whether a third dose of the original vaccine might prove effective for new forms of SARS-CoV-2. According to BioNTech chief executive Dr. Ugur Sahin his company is, “talking to regulators around the world about what types of clinical trials and safety reviews would be required to authorize a new version of the Pfizer-BioNTech vaccine that would be better able to head off the variant in South Africa.” BioNTech thinks they could develop an “adjusted” vaccine against new variants in around six weeks, while FDA has not commented about its policies for updated vaccine approval. Noting that the flu vaccine is updated yearly without an extensive regulatory process, the Times reports that some expert scientists think the COVID-19 updates should likewise not face the same scrutiny as the original products.

SARS-CoV-2 Mutating From South Africa to Brazil

While experts expected mutations and concomitant evolution in the SARS-CoV-2 virus, the quick appearance of new variants was a surprise. Due to the “sheer ubiquity” of the virus, with [as of January 25] almost 100 million cases, each infection gives more opportunity for mutation. “The more people infected, the more likely that we will see new variants,” offered Dr. Michel Nussenzweig, immunologist from Rockefeller University in New York. “If we give the virus a chance to do its worst, it will.” Several variants have concerned scientists. One, detected in Britain first, is more contagious than the original variant, and it might be “slightly more deadly.” Scientists in South Africa found another variant following a jump in cases in October, and in December they informed the WHO that the mutations may, “make the virus less susceptible,” to current vaccines. Another variant in Brazil has similar mutation to the South African strain, “but genetic evidence suggests that the two variants evolved independently.” The British variant has been seen in 20 US states, and Minnesota officials have announced that they had, “documented the first case of infection with the Brazilian variant.”

Virus Evolving

On January 29, the Times again weighed in with, “Johnson & Johnson’s Vaccine Offers Strong Protection but Fuels Concern About Variants.” The firm announced that Friday that its vaccine provides “strong protection” against COVID-19. But they also caution that the efficacy rate, at 72 percent in the US, dropped to 57 percent in South Africa where the new strain is centered. And some studies suggest that this strain also limits the effectiveness of the other vaccines available in the US. The South African variant has been found in at least 31 nations, including two cases documented in the US as of January 29. J&J planned to apply for an EUA in the week following the Times article, with a hoped-for approval date in February. “This is the pandemic vaccine that can make a difference with a single dose,” offered Dr. Paul Stoffels, chief scientific officer of J&J. The African variant, B.1.351 (also called 501Y.V2), has sped through South Africa so fast that it may make up a large proportion of US cases by April. Vaughn Cooper, who is an evolutionary biologist at the University of Pittsburgh notes that new variants have likely been evolving for months before showing; as he says, “I think we’re going to see many stories like this.” In Britain, Novavax has announced an efficacy rate of almost 90 percent there, but a small trial in South Africa showed a rate under 50 percent. J&J is now tailoring its vaccine with a B.1.351 protein shape that scientists hope would make it work on that variant.

 Novavax and Beyond

Nature took a more detailed look at the Novavax story on January 29. The firm announced that its experimental vaccine works against “rapidly spreading variants,” but the data is not great. As the Times mentioned, the vaccine was 85 percent effective against the UK strain, but only 50 percent effective against the South African strain. The findings were announced on January 28 by the team which led the South Africa trial of this protein-based vaccine. The trials included about 15,000 patients in the UK and over 4,400 in South Africa. The results likely mean that this and other variants will probably cause a substantial reduction is vaccine efficacy, opines David Ho, Columbia University virologist. His team was one of those that showed a link between 501Y.V2 and declining efficacy in antibodies brought on by the Pfizer and Moderna vaccines.

“It’s a Different Pandemic Now”

Reuters also waded into the virus-variant efficacy issues on January 30, focusing on the need to vaccinate as many people as possible as soon as possible to slow down viral evolution. Noting that both the Novavax and the J&J products were, “significantly less effective” at stopping COVID-19’s South African variant. “Clearly, the mutants have a diminishing effect on the efficacy of the vaccines,” Dr. Anthony Fauci, director of the NIAID opined. “We can see that we are going to be challenged.” In J&J’s release they said that their product was 66 percent effective across three continents. In the US they found a 72 percent efficacy rate, compared with 57 percent in South Africa where B 1.351 makes up 95 percent of reported COVID-19 cases. With new variants on the move, many wonder how the Pfizer and Moderna candidates will hold up in efficacy. “It’s a different pandemic now,” offered Dr. Dan Barouch, a Harvard University Medical School, Beth Israel Deaconess Medical Center researcher out of Boston who helped with the J&J vaccine.