JERUSALEM (Reuters) – The coronavirus variant discovered in South Africa may to some extent evade the protection afforded by Pfizer / BioNTech’s COVID-19 vaccine, a real-world data study in Israel found, although its prevalence in the country is very low and the study has not been peer-reviewed.
The study, released on Saturday, compared nearly 400 people who tested positive for COVID-19 14 days or more after receiving one or two doses of the vaccine, with the same number of unvaccinated patients with the disease.
Among other things, it corresponded to age and gender.
According to the study from Tel Aviv University and Israel’s largest healthcare provider, Clalit, the South African variant, B.1.351, was found to account for about 1% of all COVID-19 cases in all people studied.
But among patients who received two doses of the vaccine, the prevalence of the variant was eight times higher than those who were not vaccinated – 5.4% versus 0.7%.
This suggests that the vaccine is less effective against the South African variant, compared to the original coronavirus and a variant first identified in Britain that included nearly all COVID-19 cases in Israel, the researchers said.
“We found a disproportionately higher percentage of the South African variant among people vaccinated with a second dose, compared to the unvaccinated group. This means that the South African variant can to some extent break through the protection of the vaccine, ”said Adi Stern of Tel Aviv University.
However, the researchers cautioned that the study only had a small sample of people infected with the South African variant due to its rarity in Israel.
They also said the study was not intended to infer the overall effectiveness of the vaccine against any variant, as it only looked at people who had already tested positive for COVID-19, not the overall infection rates.
Pfizer declined to comment on the Israeli study.
Pfizer and BioNTech said on April 1 that their vaccine was about 91% effective in preventing COVID-19, citing updated study data with participants vaccinated for up to six months.
They tested a third dose of their shot as a booster and said they can adjust the shot as needed to specifically target new variants.
Regarding the South African variant, they 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 received the placebo. Of those nine cases, six were among individuals infected with the South African variant.
Some previous studies have shown that the Pfizer / BioNTech shot was less powerful against the B.1.351 variant than against other variants of the coronavirus, yet provided a robust defense.
VARIANT IS NOT WIDE
While the results of the study may be concerning, the South African species’ low prevalence was encouraging, said Stern of Tel Aviv University.
“Even if the South African variant breaks through the vaccine’s protection, it has not yet spread widely among the population,” said Stern, adding that the British variant could “block” the spread of the South African species.
Nearly 53% of Israel’s 9.3 million residents have received both doses of Pfizer. Israel has largely reopened its economy in recent weeks, while the pandemic appears to be easing, with a sharp decline in infections, serious illness and hospital admissions.
About a third of Israelis are under the age of 16, which means they are still not eligible for inclusion.
Reporting by Maayan Lubell Editing by Pravin Char and Frances Kerry