On Monday, MyHeritage lab, Israel’s largest COVID-19 testing lab which handles more than 10,000 tests a day, released findings of a study that found evidence indicating that the Pfizer-BioNTech vaccine significantly reduces the transmissibility of the coronavirus.
In a study co-authored by several prominent scholars, including leading COVID-19 statistician Eran Segal of the Weizmann Institute of Science, the MyHeritage lab claimed that positive test results of patients age 60 and over had up to 60 percent smaller viral loads on the test swab than the 40-59 age group, starting in mid-January, when most of Israel’s population age 60-plus had already been vaccinated with at least one dose.
The results, which were posted online, are based on partial data because MyHeritage did not know if individual samples came from patients who had been vaccinated or not. But overall, the results appear to show that once someone is vaccinated, even if they have the virus in their system, they are less likely to pass it on because they have fewer infectious SARS-CoV-2 droplets hanging around their noses and throats.
“Our result reflects great data, because it gives exactly what we want from a vaccine, namely that it reduces transmission,” Prof. Yaniv Erlich, head of the MyHeritage lab, told The Times of Israel on Monday. “It shows, to some extent, that this reduces viral load in the nose and throat, which is the main channel for transmission of the virus.”
“We checked the early December and late December [data], but the viral load among 60-plus hadn’t changed,” said Erlich, a professor of computational biology at the Interdisciplinary Center in Herzliya. “And we saw the same when we checked in early January. But suddenly, during the last two weeks in January, which is when many 60-plus Israelis had finished vaccination, viral loads for this age group dropped.”
Last week, the team behind the Oxford-AstraZeneca vaccine released a similar research that was seen as optimistic on transmission, based on positive rates in PCR tests. Dr. Doug Brown, chief executive of the British Society for Immunology, was quoted saying that the study “hints” that the vaccine may be effective in stopping people from transmitting the virus, but the results were seen as far from definitive, and the level of relevance to other vaccines was unclear.