Vaccine Boosters for South African Strain Look More Likely to Be Needed - Barron's

Pfizer said there is still no clinical evidence its vaccine won't protect against the South African strain.

Robert Atanasovski/AFP via Getty Images

A new set of studies in a leading medical journal appear to increase the likelihood that drug companies will need to rapidly develop Covid-19 vaccine boosters to protect against the South African variant of the virus.

In one of the studies, published Wednesday in the New England Journal of Medicine, scientists from Pfizer (PFE), BioNTech (BNTX), and the University of Texas Medical Branch found that the Covid-19 vaccine developed by the two companies was less effective by “approximately two thirds” at neutralizing a lab-built virus resembling the South African strain than it was at neutralizing the original virus.

The scientists said it remains unclear what the reduction in neutralization they observed in the lab means for real-world protection from the South African strain, known as B. 1.351.

In a statement, Pfizer and BioNTech said that there was still no clinical evidence that their vaccine wouldn’t protect against the South African strain.

“Nevertheless, Pfizer and BioNTech are taking the necessary steps, making the right investments, and engaging in the appropriate conversations with regulators to be in a position to develop and seek authorization for an updated mRNA vaccine or booster once a strain that significantly reduces the protection from the vaccine is identified,” the companies said.

Still, looking at the data, at least one analyst didn’t buy it. In a note out early Thursday, SVB Leerink analyst Geoffrey Porges said he expected “significant numbers” of cases of Covid-19 in people exposed to B. 1.351 who had been vaccinated with the Pfizer vaccine. A new version of the vaccine that can protect against the strain is needed, he said.

“We believe that this new version will definitely be required and presume that Pfizer is not declaring as much simply to avoid undermining confidence and uptake for their first-generation product,” Porges wrote.

In a response on Thursday morning, Pfizer reiterated that it thinks the vaccine protects against the South African strain. “While we have observed relatively lower neutralization with the South Africa strain and continue to evaluate this strain and the Brazilian one, we believe this is unlikely to translate into a significant reduction in protection provided by our current vaccine, and have not seen any real world evidence of this to date,” the company said in a statement to Barron’s.

Pfizer also said it was monitoring developments in Israel, in particular, to learn more about the performance of the vaccine against certain variants, particularly the U.K. type.

The company, along with other developers of coronavirus vaccines, is expecting substantial sales of the product in 2021. Pfizer has said it expects to earn $15 billion from its Covid-19 vaccine in 2021. 

The company has sold 300 million doses to the U.S. government, which President Joe Biden  said last week could be delivered by the end of July. Pfizer CEO Albert Bourla told Barron’s on Feb. 2 that the company isn’t working on a booster to protect against the South African strain, though it is doing lab work to prepare in case it determines that a booster against some strain is eventually necessary.

But Porges wrote that the immunity provided by the Pfizer vaccine against the South African strain “seems to be marginal,” if current assumptions about how the lab tests used in the paper relate to real-world efficacy bear out.

According to the CDC, as of Tuesday, there had been 19 cases of the B. 1.351 variant so far identified in the U.S., in 10 different states.

Also on Wednesday, the New England Journal‘ published a letter to the editor written by Moderna (MRNA) scientists, with colleagues at the National Institute of Allergy and Infectious Diseases, on tests of the Moderna Covid-19 vaccine against lab-built variants of the virus that causes Covid-19, including a pseudovirus resembling the B. 1.351 strain. The scientists found “a decrease in titers of neutralizing antibodies against the B. 1.351 variant,” they wrote.

“Protection against the B. 1.351 variant conferred by the mRNA-1273 vaccine remains to be determined,” the scientists said. “Our findings underscore the importance of continued viral surveillance and evaluation of vaccine efficacy against new viral variants.”

In late January, Moderna said it would develop a booster to protect against the B. 1.351 variant.

Neither Pfizer nor Moderna have published data from real-world studies in South Africa to determine how their vaccines perform against the strain. Vaccines that have been tested there have demonstrated diminished protection against B. 1.351, including the AstraZeneca (AZN) vaccine, which appeared in a small study to provide “minimal protection” against mild to moderate Covid-19 infection from the strain.

In a separate study, Johnson & Johnson’s (JNJ) Covid-19 vaccine was found to be as effective in preventing severe disease in South Africa, where the B. 1.351 strain is dominant, as it was in other countries, even though it was less effective at preventing moderate to severe disease there than it was elsewhere. Earlier this week, South African officials said they planned to focus on distributing the Johnson & Johnson vaccine, backing away from earlier plans to use the AstraZeneca vaccine.

Shares of Pfizer were down 0.2% in premarket trading, while shares of BioNTech were down 2.7%, and shares of Moderna were down 1%.

Write to Josh Nathan-Kazis at josh.nathan-kazis@barrons.com

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February 18, 2021 at 09:25PM
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Vaccine Boosters for South African Strain Look More Likely to Be Needed - Barron's

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