Tel Aviv University & Clatit Study Reveals South African Variant may ‘Break’ BNT62b2, Meanwhile Israel Heads out of Pandemic

Tel Aviv University & Clatit Study Reveals South African Variant may ‘Break’ BNT62b2, Meanwhile Israel Heads out of Pandemic

A recent study led by Tel Aviv University and Clatit, Israel’s second largest healthcare provider, found that the South African variant of SARS-CoV-2, known as B.1.351, while only an estimated 1% of all COVID-19 cases, in the study population can actually “break through” the mRNA-based vaccine called BNT162b2, produced by Germany’s BioNTech in partnership with American multinational pharmaceutical company Pfizer. Based on a real-world data study in Israel comparing nearly 400 people affirmed positive for COVID-19 and after receiving one or two doses of the vaccine versus the same number of unvaccinated individuals affirmed positive with SARS-CoV-2. This observational study matches other demographic attributes, from gender to age. A disturbing finding occured: the South African variant’s prevalence rate turns out to be eight times higher in the vaccinated versus the unvaccinated group totaling -5.4% versus 0.7%.  While this is just the result of one observational study and no conclusions can be made, the study suggests that the BNT162b2 vaccine is actually less effective against B.1.351 as compared to the original SARS-CoV-2 and the UK variant that represents most cases in Israel, reports the team from Tel Aviv University.

Principal Investigator Point of View

Study lead Professor Adi Stern, an accomplished virologist at Tel Aviv University, declared for the public, “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.” TrialSite shares a recent update made possible thanks to Maayan Lubell with Reuters.

High Effective Rate Reported for BNT162b2

Recently the partnered companies Pfizer and BioNTech reported to the world that the vaccine was about 92% effective at preventing COVID-19, referring to a recent study data covering participants post six months the initial jab.

While some previous studies pointed to perhaps less potency against the South African strain, a recent Pfizer/BioNTech study concluded overwhelming potency.

The recent Pfizer press release noted that in South Africa, where B.1.351 is prevalent, 800 study participants enrolled in a recent study. In all nine cases of COVID-19 there were observed, all were in the placebo group, indicating a vaccine efficacy of 100% against the South African variant (95% CI, [53.5, 100.0]). Six of the nine positive cases were associated with the B.1.351 strain. Overall, the Pfizer study indicates highly robust neutralizing abilities of BNT162b2 against the South African strain.

Limitations of Current Israeli Observational Study

First, it should be noted that B.1.351 represents only 1% of the sample population, meaning that it doesn’t appear to be a significant presence in this nation along eastern Mediterranean. Moreover, this was a relatively small observational study so no strong conclusions can be made from the study. As explained in a recent Reuters article, the research wasn’t intended to come to overall vaccine effectiveness against a particular variant as investigation only focused on those already affirmed COVID positive.

Vaccination Nation Heading toward Normalcy 

Professor Stern isn’t too concerned, given first and foremost, the limited spread of the South African variant in Israel. The Israeli professor declared recently, “Even if the South African variant does break through the vaccine’s protection, it has not spread widely through the population.”  Interestingly, Professor Stern suggested that the UK variant could be “blocking” the South African strain’s dissemination in this country.

Israel led the world in vaccinations against the coronavirus. Perhaps indicative of the highly organized and thoughtful leadership and populace, nearly 53% of the 9.3 million people living in this country received both doses of the mRNA-based BNT162b2 (Pfizer/BioNTech vaccine). Now with such widespread vaccination and a generally adherent population to safety measures, the pandemic now wanes and the population appears to be headed back outside, leading to an opening economy.

Lead Research/Investigator

Adi Stern, PhD, MSc


  1. I have seen a couple generic news articles on these “break through” cases. They neglect to mention which of the vaccines they’re talking about, or where these cases are occurring, only that this is happening to people who are a couple weeks past their 2nd shot. And they aren’t mentioning which variant either. Last time I checked, the UK B.117 was the most prevalent variant in the USA, but that can change in a couple months.

    OTOH I have seen a few news articles saying how the vaccines can handle the variants. NBC ran one this weekend. Their links eventually trace back to a paper that discuses diluted serum titers when research monkeys were given a 10% strength dosage of the Moderna 1273 vaccine, and how this was still sufficient. The NBC story closes with the slightly hopeful observation that real world results will be the real proof. But at least this team has looked at both the B.117 and B.1351 variants, along with a couple others.

    Half the authors of this paper work for Moderna, several others are inventors of some of the patented aspects of that vaccine.