The Slatest

Study: Pfizer COVID-19 Vaccine May Be Less Effective Against South African Variant

Vials containing doses of the Pfizer COVID-19 vaccine are viewed at a clinic targeting minority community members at St. Patrick's Catholic Church on April 9, 2021 in Los Angeles, California.
Vials containing doses of the Pfizer COVID-19 vaccine are viewed at a clinic targeting minority community members at St. Patrick’s Catholic Church on April 9, 2021 in Los Angeles, California. Mario Tama/Getty Images

The Pfizer/BioNTech’s COVID-19 vaccine may not provide as much protection against a variant that was first discovered in South Africa, according to a preliminary study in Israel. The research has not been peer reviewed yet but suggests the B.1.351 variant can penetrate the protection offered by the two doses of the vaccine, although it isn’t clear exactly how much effectiveness it loses.

The study, carried out by researchers at Tel Aviv University and Clalit, Israel’s largest health care organization, compared almost 400 people who tested positive for COVID-19 at least two weeks after they received one or two doses of the Pfizer vaccine. It compared it against the same number of people who contracted COVID-19 and were not vaccinated. Only about 1 percent of the people who took part in the study were infected with the South African variant. But the difference between the vaccinated and unvaccinated was stark. Whereas only 0.7 percent of those who were not vaccinated had contracted the South African variant, the prevalence was 5.4 percent among those who had been vaccinated.

The results suggests the vaccine may be less effective when confronted with this variant of the virus. “We found a disproportionately higher rate of the South African variant among people vaccinated with a second dose, compared to the unvaccinated group. This means that the South African variant is able, to some extent, to break through the vaccine’s protection,” said Tel Aviv University’s Adi Stern. The sample size, however, was too small to figure out exactly how much less effective it is with the new variant.

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