The coronavirus variant found in South Africa may “break” the Pfizer-BioNTech COVID-19 vaccine to some extent, an Israeli study found.
The South African variant of the coronavirus has managed to penetrate to some extent the protection offered by two doses of Pfizer-BioNTech vaccine, although it remains unclear how much efficacy is lost, he said.
The study, launched on Saturday, compared nearly 400 people who tested positive for COVID-19 two weeks or more after receiving one or two doses of the vaccine to the same number of unvaccinated patients.
It matched age and gender, among other features.
The South African variant, B.1.351, was found to account for about 1 percent of all COVID-19 cases in all individuals studied, according to a study by Tel Aviv University and Israel’s largest healthcare provider, Clalit.
But among patients who received two doses of the vaccine, the prevalence rate of the variant was eight times higher than those who were not vaccinated – 5.4 percent compared to 0.7 percent.
This suggests that the vaccine is less effective against the South African variant compared to the original coronavirus and a variant first identified in the UK, which has come to cover almost all cases of COVID-19 in Israel, the researchers 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 version is able, to some extent, to break the vaccine protection, “said Adi Stern, Tel Aviv University, who led the study.
However, the researchers warned that the study had only a small sample of people infected with the South African variant because of its rarity in Israel.
They also said that the research was not intended to deduce 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 and BioNTech could not be reached immediately for comments outside of business hours.
The companies said on April 1 that their vaccine was about 91% effective in preventing COVID-19, citing updated data from studies that included inoculated participants for up to six months.
Regarding the South African version, they said that among a group of 800 studied volunteers from South Africa, where B.1.351 is widespread, there were nine cases of COVID-19, all of which occurred among participants who had received a placebo.
Of the nine cases, six were infected with the South African variant.
Some previous studies have shown that the Pfizer-BioNTech shot was less potent against variant B.1.351 than against others of the coronavirus, but still provided a robust defense.
While the results of the study may cause concern, the low prevalence of the South African strain has been encouraging, according to Stern.
“Even though the South African version penetrates through vaccine protection, it has not spread widely among the population,” Stern said, adding that the British version could “block” the spread of the South African strain.
Nearly 53 percent of Israel’s 9.3 million population received both doses of the Pfizer-BioNTech vaccine.
Israel has largely reopened its economy in recent weeks as the pandemic appears to be receding, with the rate of infections, severe disease and hospitalizations falling sharply.
About a third of Israelis are under the age of 16, which means they are not yet eligible for shooting.