South African COVID-19 strain can 'break through' vaccine: researchers

An Israeli study released on Saturday found that the coronavirus variant first detected in South Africa is able to “break through” the antibodies created from the Pfizer-BioNTech vaccine to some extent.

The study was carried out by Tel Aviv University and Israel’s largest health care provider Clalit, Reuters reported.

The study compared around 400 people who tested positive for COVID-19 after receiving one or more doses of the Pfizer vaccine to the same number of unvaccinated people who had also tested positive. The outlet noted that Israel does not have a high prevalence of the South African variant and that the research has not been peer reviewed.

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Researchers qualified the results of their study by noting that they were not meant to evaluate overall vaccine effectiveness and added that the sample size was small.

The variant, B.1.351, was found in 1 percent of all people studied, but its prevalence rate was eight times higher among those who received two doses of the vaccine than among those who were unvaccinated, at 5.4 percent and 0.7 percent, respectively.

“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,” Tel Aviv University researcher Adi Stern said, according to Reuters.

Stern added, however, that "even if the South African variant does break through the vaccine’s protection, it has not spread widely through the population."

Reuters notes that a study conducted by Pfizer in South Africa found only nine coronavirus cases out of 800 participants, all of whom had received a placebo dose. Six of the infected individuals were found to have the South African variant. Prior studies have indicated that the Pfizer vaccine is less effective against the South African variant but still offered protection against the strain.