COVID-19: South African variant may 'break through' Pfizer-BioNTech vaccine, says study

A recent study has found that the coronavirus variant found in South Africa can break through the protection provided by Pfizer Inc and BioNTech’s COVID-19 vaccine to some extent. The study released on the medRxiv site has not yet been peer-reviewed but the researchers have said that the COVID-19 variant’s prevalence in Israel is very low and the vaccine remains highly effective. The researchers said that it compared almost 400 people who had tested positive for COVID-19, after they received one or two doses of the vaccine, against the same number of unvaccinated patients with the disease. 

According to the study by Tel Aviv University and Israel's largest healthcare provider, Clalit, The South African variant, B.1.351 was found to make up about 1 per cent of all the COVID-19 cases across all the people studied. However, among patients who had received two doses of the vaccine, the variant’s prevalence rate was eight times higher than those unvaccinated. The researchers said that this suggests the vaccine is less effective against the South African variant, compared with the original coronavirus and a variant first identified in Britain that has come to comprise nearly all COVID-19 cases in Israel. 

‘B.1.351 variant to break through vaccine’s protection’ 

Further, the researchers said that the study was not intended to assess overall vaccine effectiveness against any variant, since it only looked at people who had already tested positive for COVID-19 not at overall infection rates. In a separate study on the vaccines overall effectiveness, Clalit found that the Pfizer shot is more than 90 per cent effective. 

Tel Aviv University's Adi Stern said, “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”. 

"The B.1.351 incidence in Israel to-date remains low and vaccine effectiveness remains high among those fully vaccinated," the study added.

The Israeli study comes after Pfizer-BioNTech had said that their vaccine was around 91 per cent effective at preventing COVID-19, citing updated trial data that included participants inoculated for up to six months. In respect to the South African variant, Pfizer said that among a group of 800 study volunteers in South Africa, where B.1.351 is widespread, there were nine cases of COVID-19, all of which occurred among participants who got the placebo. Out of those nine cases, six were among individuals infected with the South African variant. Some studies have indicated that the Pfizer-BioNTech show was less potent against the South African variant, but still, it offered a powerful defence. 

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