A study of real data in Israel found that the coronavirus variant discovered in South Africa could compromise the protection of Pfizer Inc and BioNTech’s COVID-19 vaccine to some extent. However, the prevalence of the variant in Israel is very low and the vaccine is still very effective.
The research was published on the preprint website medRxiv on April 9 and has not been peer-reviewed. It compared nearly 400 people who tested positive for the COVID-19 virus, after receiving one or two doses of the vaccine, with the same number of unvaccinated patients with the disease.
They match their age and gender, among other things.
The South African variant, B.1.351, was found to be responsible for about 1% of all COVID-19 cases of all people studied, according to the study from Tel Aviv University and the largest healthcare provider in Israel, Clalit.
But among patients who received two doses of the vaccine, the prevalence of the variant was eight times higher than that of the unvaccinated patients: 5.4% versus 0.7%.
The researchers said this indicates that the vaccine is less effective against the South African variant, compared to the original coronavirus and the variant first identified in Britain that now accounts for nearly all cases of COVID-19 in Israel. houses.
The researchers said the study was not aimed at assessing the overall effectiveness of the vaccine against any variant, as it only looked at people who had already tested positive for COVID-19, not overall infection rates.
Separate real-world Israeli studies on the overall effectiveness of the vaccine, including those conducted by Clalit, have shown that the dose of Pfizer is over 90% effective. L1N2KU3L6
“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 penetrate vaccine protection to some extent, ”said Thiel. Uday Stern from Tel University.
In a study update published April 16, researchers noted that within the group of people who received two doses, including eight people, all B.1.351 infections occurred within a week to 13 days after the second injection. None of them tested positive 14 days or more after the second dose.
“This may mean that there is a short period of susceptibility to infection with B.1.351 that is limited to the two weeks after the second dose – but we cannot be sure that this is indeed the case,” said Ran Balaiser. Stern and Clalit. in an email.
However, the researchers cautioned that the study includes only a small sample of people infected with the South African variant due to its rarity in Israel.
The study said, “The incidence of B.1.351 in Israel so far is still low and the effectiveness of the vaccine is still high among those who have been fully vaccinated.”
Pfizer(PFE.N) He declined to comment on the Israeli study. Pfizer and BioNTech(22UAy.DE) He said on April 1 that their vaccine was 91% effective in preventing COVID-19, citing updated study data with participants vaccinated for up to six months.
They tested a third dose of the shot as a booster and said they could adjust the shot as needed to specifically address the new variants.
Regarding the South African variant, they said that among a group of 800 volunteers studying 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 those infected with the South African variant. read more
Some previous studies indicated that the Pfizer / BioNTech shot was less effective against the B.1.351 variant compared to other types of coronavirus, but it still provided a strong defense.
While the study results may be concerning, the low prevalence of the South African subspecies was encouraging, according to Stern.
Stern said, “Even if the South African alternative penetrates the vaccine’s protection, it will not spread widely among the population,” adding that the British alternative could “prevent” the spread of the South African tribe.
More than half of Israel’s 9.3 million residents have received two doses of Pfizer. Israel has largely reopened its economy in recent weeks, while the epidemic appears to be easing with a sharp drop in infections and hospital admissions.
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