Individuals vaccinated by the Pfizer coronavirus vaccine are not only less likely to contract COVID-19, but they are also less likely to share it, according to a new study published by Sheba Medical Center on Sunday.
The study found that vaccinated family members are around 50% less likely to infect each other with coronavirus if one of them becomes sick.
According to the report, published by Sheba, the French Pasteur Institute and Sorbonne Université on the non-peer-reviewed medical sharing platform MedRxiv, the risk of vaccinated family members being infected by a family member who became ill even though he or she was vaccinated is 4% compared to the risk of an unvaccinated family member being infected by an unvaccinated family member, which is 57%.
But it should be noted that the figure did vary depending on certain parameters, such as the age of the vaccinated and non-vaccinated individuals and the amount of time spent together.
The study also found that when those who were infected isolated themselves, the chance of family members getting infected dropped between 80% to 90%.
“The findings of this study reinforce findings from previous studies conducted at Sheba that indicate that vaccinated people not only get infected less, but they also infect others less,” said Prof. Gili Regev-Yochay, director of the Infectious Disease Epidemiology Unit at Sheba, who led the study.
The hospital followed the households of some 12,518 healthcare workers between the end of December 2020 and March 2021, conducting this specific research among 210 families (902 people), of whom 191 adults and 24 children under 12 tested positive for the virus.
The study was conducted when the Alpha variant was the predominant strain in the country. The researchers said that the statistics might be different when talking about the Delta variant, which is currently dominant in Israel and the world.
Specifically, the study showed that the chance of an unvaccinated adult infecting another unvaccinated adult stood at 57%. The chance of the unvaccinated adult infecting an unvaccinated child stood at 35%. On the other hand, if the infected person was vaccinated, the chance of infecting an unvaccinated adult that he or she lives with dropped to 17%. Finally, the chance of two vaccinated people infecting each other was 4%.
“For the first time, we were able to quantify the true risk of contracting coronavirus after significant exposure among vaccinated, unvaccinated, isolated people and adults compared to children,” Regev-Yochay said.
The findings also showed that isolation from a household member with coronavirus is “necessary” and “effective,” the professor added – even if other members of the household are vaccinated.
“This study is further evidence of the importance of raising the vaccination rate in Israel and the world,” Regev-Yochay continued. “It is the only effective way to reduce the pandemic and return to routine life alongside the coronavirus.”