According to a real-world data study in Israel, the coronavirus strain discovered in South Africa can “break through” Pfizer/BioNTech’s COVID-19 vaccine to some degree.

However, the researchers warned that since the South African strain is uncommon in Israel, the report only had a limited sample size of people infected with it, and the test has not been peer-reviewed.

The New York Post reports that the research, published on Saturday, April 10, by Tel Aviv University and Clalit, Israel’s largest healthcare provider, compared nearly 400 individuals who tested positive for COVID-19 for 14 days or more after receiving one or two doses of the vaccine to the same number of unvaccinated patients with the disease. They matched age and gender, among other characteristics.

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

According to the study, the South African type B.1.351 accounts for around 1% of all COVID-19 cases among all people surveyed.

However, the prevalence of the variant was eight times higher in patients who had administered two doses of the vaccine than among those who had not – 5.4% versus 0.7%.

According to the experts, this indicates that the vaccine is less successful against the South African variant than against the original coronavirus and a variant first detected in Britain that now accounts for almost all COVID-19 cases in Israel.

They also mentioned that the study was not designed to determine total vaccine efficacy against any variant. It only looked at patients who had previously tested positive for COVID-19, not overall infection rates.

While the study’s findings may be concerning, Stern believes that the South African strain’s low prevalence is encouraging as this variant “has not spread widely through the population,” adding that the British variant may be “blocking” the spread of the South African strain.

Previously, Pfizer informed nine cases of COVID-19 among 800 research volunteers in South Africa, where B.1.351 is common. All of the cases occurred among those who received the placebo. Six of the nine cases included people infected with the South African strain.

The new data research comes as public health authorities worry that highly infectious variants, shown in experiments to decrease vaccine efficacy, could stymie global progress on the pandemic.

As the variants disperse, drugmakers are experimenting to see whether a third dose will have more safety.

Pfizer and BioNTech announced in February that they were investigating a third dose of their Covid-19 vaccine to help recognize the immune response to new virus variants.

In December 2020, Israel initiated a nationwide vaccination program aimed at people aged 60 and over, healthcare workers, and people with comorbid conditions. By February 2021, it had surpassed the United States as the world leader in vaccines, inoculating millions of its people against the virus.

As previously reported, a group of Israelis, including doctors, lawyers, activists, and concerned citizens linked to the Anshe Ha-Emet (People of Truth) community who accuse the government of “crimes against humanity” for not asking for the respective “informed consent” for the vaccination, sued Prime Minister Benjamin Netanyahu’s government in the International Court of Justice for violating the Nuremberg Code by experimenting on citizens using controversial mRNA vaccines against the COVID-19.

Outrage over forced vaccination in Israel increased when Pfizer CEO Albert Bourla called Israel a “global laboratory” for its vaccines in an interview with NBC News in February 2021. Pfizer doses have been given to nearly 53% of Israel’s 9.3 million people at the present time.