Israeli studies found that the Pfizer COVID-19 vaccine reduces transmission

JERUSALEM (Reuters) – Pfizer’s COVID-19 vaccine greatly reduces virus transmission, according to two Israeli studies, which shed light on one of the most important issues in the global effort to end the pandemic.

Data analysis in a study by the Israeli Ministry of Health and Pfizer Inc. found that the Pfizer vaccine developed with German BioNTech reduces infection, even in asymptomatic cases, by 89.4% and in symptomatic cases by 93 , 7%.

Israeli news site Ynet first reported the findings of the pre-published study, not yet peer-reviewed, but based on a national database that is one of the most advanced in the world, and obtained Reuters on Friday. .

Pfizer declined to comment and the Israeli Ministry of Health did not respond to any requests for comment.

A separate study from Israeli Sheba Medical Center published Friday in the medical journal The Lancet found that among 7,214 hospital staff who received their first dose in January, there was an 85% reduction in symptomatic COVID-19 within a period of 15 to 28 days, with an overall reduction in infections, including asymptomatic cases detected by tests, of 75%.

More research is needed to draw a definitive conclusion, but studies are among the first to suggest that a vaccine can stop the spread of the new coronavirus and not just prevent people from getting sick.

Michal Linial, a professor of molecular biology and bioinformatics at the Hebrew University of Jerusalem, said the findings were a big step toward answering one of the most important questions in the fight against the pandemic.

“Whether it’s a 75% or a 90% reduction, it doesn’t matter, it’s a big drop in transmission,” Linial said. “It means that the vaccinated person is not only protected, but inoculation also provides protection to their environment.”

The researchers said an additional study on asymptomatic transmission between fully vaccinated people was needed because COVID-19 is less likely to be tested.

Vaccine developers have also said more research is needed on transmissibility. In December, German BioNTech said it would take another three to six months under study.

“DYNAMIC VIRUSES”

At the forefront of the world in its deployment of vaccinations, Israel’s universal health capability and advanced data have provided a nationwide database that can provide information on the effectiveness of vaccines outside of controlled clinical trials.

The Ministry of Health / Pfizer study analyzed data collected between January 17 and February 6, which examined people who had been completely vaccinated after receiving their second shot from Pfizer.

So far, more than 30%, or 2.8 million of Israel’s nine million people, have received both doses.

Sheba’s study found that only the first dose of Pfizer vaccine was 85% effective, which may fuel a debate over the recommended two-dose schedule.

Canadian researchers in a letter published this week suggested delaying the second dose of Pfizer given the high level of protection from the first shot to increase the number of people vaccinated.

The U.S. Food and Drug Administration said in December data from these trials showed that the vaccine was beginning to confer some protection on recipients before receiving the second vaccine, but more data would be needed to assess the potential for a single-dose vaccine.

Pfizer has said that alternative vaccine dosing regimens have not yet been evaluated and that the decision rested with the health authorities.

Another caveat is that the cohort studied at the hospital was “mostly young and healthy,” Sheba epidemiologist Gili Regev-Yochay said.

Unlike Pfizer’s clinical trial, “we don’t have many (staff) over 65 here,” he told reporters. But he also said Sheba’s study took place during an increase in coronavirus infections in Israel, which flooded hospitals with new cases.

Pfizer declined to comment on the data, saying in a statement that it was doing its own analysis of “the real-world effectiveness of the vaccine in several parts of the world, including Israel.”

The results of both studies were compared with overall efficacy around 95% on a two-dose regimen 21 days apart. Researchers from the Ministry of Health / Pfizer found that the vaccine was effective against the British variant of the coronavirus which accounts for approximately 80% of confirmed cases in Israel.

Eran Kopel, an epidemiologist at Tel Aviv University, said Sheba’s study was important, but focused on a hospital and a relatively small group of people, so “no clear epidemiological conclusions could be drawn. “.

Health Ministry data was encouraging, he said, but more research and regular surveys were needed.

“Vaccinations are a very good tool, but this is not the end. It is a dynamic virus that has surprised the scientific world with its rapid pace of change and variety, ”he said.