Vaccinating healthcare workers reduces risk of COVID-19 transmission to close contacts

The vaccination of healthcare workers has offered some protection against the transmission of COVID-19 to their household contacts, research has shown.

A study of all healthcare workers employed by the NHS in Scotland and their households shows the rate of infection for people that live with them is at least 30 per cent lower when the worker has been vaccinated.

As household members of healthcare workers can also catch the virus via other people, the 30 per cent relative risk reduction is likely to be a conservative estimate of the effect of vaccination on transmission.

The research led by Public Health Scotland (PHS) and the University of Glasgow involved more than 300,000 people in total and ran between 8 December 2020 and 3 March 2021.

The study, using record linkage, compared cases of COVID-19 and hospitalisations due to the virus in household members of both vaccinated and unvaccinated healthcare workers.

Where healthcare workers had received a second dose of the vaccine at least 14 days before, their household members had a rate of COVID-19 which was at least 54 per cent lower than household members where healthcare workers had not been vaccinated.

The study was not designed to examine uptake of vaccination among healthcare workers but does suggest that some patient facing healthcare workers, particularly younger staff or those not in high exposure roles, may not have been vaccinated yet.

Dr Diane Stockton, PHS lead for the COVID-19 Vaccination Surveillance Programme, said: "The results from this study, as part of our vaccine effectiveness work, are very encouraging because it suggests that the vaccine helps prevent people from passing on the virus to others - something that has been suspected but hasn't previously been shown.

"Despite this good news, it is important to remember that infection prevention and control practices in healthcare settings remain of paramount importance, as do the mitigations to prevent spread in our daily lives. The risk of transmission did not go down to zero after the healthcare worker was vaccinated.

"As Scotland continues to deliver its national COVID-19 vaccination programme, this study does give one more reason why everyone invited to have a vaccine should take up the offer, as not only will it help protect them from COVID-19, but it will help protect the people close to them."

Dr David McAllister, of the University of Glasgow, said the study had "important implications" in informing vaccination strategies.

He added: "We provide the first direct evidence that vaccinating individuals working in high-exposure settings reduces the risk to their close contacts – members of their households.

"Our work will also be of interest to modellers, as it can be used to inform their predictions about future rates of COVID-19 in the community."