JERUSALEM (Reuters) – Pfizer’s COVID-19 vaccine greatly reduces transmission of the virus, two Israeli studies found, shedding light on one of the biggest questions in the global effort to quell the pandemic.
Data analysis in a study conducted by the Israel Ministry of Health and Pfizer Inc found that the Pfizer vaccine developed with Germany’s BioNTech reduces infection, even in asymptomatic cases, by 89.4% and in symptomatic cases by 93 , 7%.
The findings of the prepublished study, not yet peer-reviewed but based on a national database that is one of the most advanced in the world, were first reported by the Israeli news site Ynet late Thursday and were obtained. by Reuters on Friday.
Pfizer declined to comment and the Israeli Health Ministry did not respond to a request for comment.
A separate study from Israel’s Sheba Medical Center published Friday in The Lancet medical journal found that among 7,214 hospital employees who received their first dose in January, there was an 85% reduction in symptomatic COVID-19 within 15 years. 28 days with a general reduction. infections, including asymptomatic cases detected by testing, 75%.
More research is needed to reach a definitive conclusion, but the studies are among the first to suggest that a vaccine can stop the spread of the new coronavirus and not just keep 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.
“It doesn’t matter if it’s a 75 or 90 percent reduction, it’s a huge drop in transmission,” Linial said. “It means that not only the vaccinated individual is protected, the inoculation also provides protection to their environment.”
The researchers said more studies were needed on asymptomatic transmission among fully vaccinated people because they are less likely to be tested for COVID-19.
Vaccine developers have also said that more research is needed on transmissibility. In December, BioNTech from Germany said it would take three to six more months to study.
Leading the world in its vaccine implementation, Israel’s universal health care and advanced data capabilities have provided a nationwide database that can provide information on the efficacy of vaccines outside of controlled clinical trials.
The Ministry of Health / Pfizer study analyzed data collected between January 17 and February 6, and looked at people who had been fully vaccinated after receiving their second injection from Pfizer.
To date, 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’s vaccine was 85% effective, which could spark debate over the recommended two-dose schedule.
In a letter published this week, Canadian researchers suggested delaying the second dose of Pfizer given the high level of protection from the first injection to increase the number of people getting vaccinated.
The U.S. Food and Drug Administration said in December that data from those trials showed that the vaccine began to confer some protection on recipients before they received the second injection, but more data would be needed to assess the potential for a single dose injection.
Pfizer has said that alternative dosing regimens for the vaccine have yet to be evaluated and that the decision rests with health authorities.
Another caveat is that the cohort studied at the hospital was “mostly young and healthy,” said Sheba epidemiologist Gili Regev-Yochay.
Unlike the Pfizer clinical trial, “we don’t have many (employees) here over the age of 65,” he told reporters. But he also said that Sheba’s study took place during a surge in coronavirus infections in Israel, which inundated hospitals with new cases.
Pfizer declined to comment on the data and said in a statement that it was doing its own analysis of “the vaccine’s effectiveness in the real world in various locations around the world, including Israel.”
The findings from both studies were compared with an overall efficacy of around 95% on a two-dose regimen 21 days apart. Health Ministry / Pfizer researchers found the vaccine to be effective against the British coronavirus variant that accounts for about 80% of Israel’s confirmed cases.
Eran Kopel, an epidemiologist at Tel Aviv University, said Sheba’s study was important, but it focused on a hospital and a relatively small group of people, so “no clear epidemiological conclusions can be drawn from it.”
The data from the Health Ministry was encouraging, he said, but more research and regular surveys were needed.
“Vaccines are a very good tool, but this is not the end. This is a dynamic virus that has surprised the scientific world with its rapid rate of change and variety, “he said.
Additional reporting from Dan Williams in Jerusalem; Editing by Jane Merriman and Barbara Lewis