The coronavirus variant discovered in South Africa may to some extent ‘break through’ Pfizer-BioNTech’s COVID-19 vaccine, according to a study in Israel.
The South African coronavirus variant managed to penetrate to some extent the protection afforded by two doses of the Pfizer-BioNTech vaccine, although it remains unclear how much efficacy is lost, it said.
The study, released Saturday, compared nearly 400 people who tested positive for COVID-19 two weeks 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 percent 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 that of unvaccinated patients – 5.4 percent versus 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 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 vaccine’s protection, ”said Adi Stern of Tel Aviv University, who led the study.
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 and BioNTech were not immediately available for comment outside office hours.
The companies said on April 1 that their vaccine was about 91 percent effective in preventing COVID-19, citing updated study data with participants vaccinated for up to six months.
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 individuals who were 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 others from the coronavirus, yet provided a robust defense.
While the results of the study may be concerning, the low prevalence of the South African species was encouraging, according to Stern.
“Even if the South African variant breaks through the vaccine’s protection, it will not have spread widely among the population,” said Stern, adding that the British variant could “block” the spread of the South African strain.
Nearly 53 percent of Israel’s 9.3 million residents have received both doses of the Pfizer-BioNTech vaccine.
Israel has largely reopened its economy in recent weeks as the pandemic seemed to ease, with a sharp decline in infections, serious illnesses and hospitalizations.
About one-third of Israelis are under the age of 16, which means they are still not eligible for inclusion.