The study, which has not yet been peer-reviewed, indicated that the B.1.351 variant of the virus was found eight times more in individuals who were vaccinated—or 5.4 percent against 0.7 percent—against those who were not vaccinated. Clalit Health Services, a top Israeli health-care provider, also helped in the study.
“We found a disproportionately higher rate of the South African variant among people vaccinated with a second dose, compared to the unvaccinated group,” said Adi Stern of Tel Aviv University. “This means that the South African variant is able, to some extent, to break through the vaccine’s protection.”
The study looked at 400 people who received at least one shot of the Pfizer/BioNTech vaccine and had contracted the COVID-19 variant and compared them to the same number of people who were infected and unvaccinated. Moderna’s vaccine is also used in Israel, but it was not included in the study.
“It is the first in the world to be based on real-world data, showing that the vaccine is less effective against the South Africa variant, compared to both the original virus and the British variant,” said Professor Ran Balicer, director of research at Clalit, according to news reports.
Stern said the study’s findings came as a surprise.
“Based on patterns in the general population, we would have expected just one case of the South African variant, but we saw eight,” Stern told the Times of Israel. “Obviously, this result didn’t make me happy.” He added, “Even if the South African variant does break through the vaccine’s protection, it has not spread widely through the population.”