A man receives his third dose of the coronavirus disease (COVID-19) vaccine at the Clalit Healthcare Maintenance Organisation in Jerusalem, August 13, 2021. REUTERS/Ammar Awad

Vaccinated parents can indirectly protect their children who are not inoculated from the risk of getting infected with the coronavirus, according to a peer-reviewed study led by an Israeli research team.

Children living in households with two vaccinated parents during the outbreak of the Alpha variant, in early 2021, had a 72 percent lower risk of contracting the virus than those who lived with unvaccinated parents, according to the study, carried out by researchers at the Clalit Research Institute, in collaboration with researchers from Harvard University and Tel Aviv University. In households with a single vaccinated parent, the risk was 26 percent lower.

“While the age range for vaccination continually expands, many children and adolescents remain unvaccinated for different reasons,” stated Dr. Noam Barda, head of Epidemiology and Research at Clalit Research Institute. “The current study shows that parental vaccination confers substantial protection for children living in the same household, emphasizing that vaccination not only protects vaccinated individuals, but also their loved ones.”

The authors of the peer-reviewed study, published in the Science journal, concluded that the results “reinforce the importance of increasing vaccine uptake among the vaccine-eligible population to curb the spread of the SARS-CoV-2 pandemic and protect those who cannot be vaccinated.”

The study analyzed data from Israel’s largest healthcare organization using a sample of 155,305 households. Researchers looked at families without prior infection during two separate periods, between January 17, 2021 and March 28, 2021, during the Alpha outbreak, and between July 11, 2021 to September 30, 2021 during the outbreak of the Delta variant. They also found that vaccinated parents are less likely to transmit COVID-19 to other household members if infected.

Results of the study covering the Delta wave, which used data from 76,621 households, showed that unvaccinated children living with two boosted parents had a 58.1 percent lower risk for infection. In a single boosted parent household, a 20.8 percent decreased risk for infection was recorded for unvaccinated children.

“This study highlights the indirect protection provided by vaccinated parents to their unvaccinated children, irrespective of household size or the child’s age, for both the Alpha and the Delta variants,” said Dr. Samah Hayek, senior researcher at Clalit Research Institute.

Prof. Ran Balicer, Chief Innovation Officer of Clalit, pointed out that “by quantifying the indirect protection provided from vaccinated parents to unvaccinated children, several mechanisms of protection emerge, including lower transmission from vaccinated parents with a breakthrough infection to their unvaccinated children, as compared with unvaccinated parents.”