Findings from a Scottish study show that a single vaccine dose offers as much protection from severe COVID-19 to people who were previously on the shielding list as it does for the rest of the population.

The yet to be peer-reviewed study, led by Public Health Scotland and supported by the University of Edinburgh, examined the effectiveness of the vaccine using data from over 100,000 people to determine its impact on reducing severe COVID-19 among those designated as clinically extremely vulnerable.

Some medical conditions and certain medicines that affect the immune system can make people extremely vulnerable to COVID-19. As a result, this group were advised to take extra precautions during the first few months of the pandemic, including shielding at home.
There are also concerns that a weakened immune system not only puts some people at greater risk of the complications of COVID-19, but that it may also reduce the effectiveness of the vaccines they receive.

Reassuringly, the researchers found that the efficacy of a single vaccination dose in protecting against severe COVID-19 was as high or higher in those eligible for shielding as in those without risk conditions.

Discussing the findings, Dr Nicholas Phin, Director of Public Health Science at Public Health Scotland, said;

“Those that are considered clinically extremely vulnerable are about six times more likely to experience severe COVID-19 leading to hospitalisation or death, than someone the same age without their condition.

“The results of this study are therefore hugely encouraging in showing that vaccination amongst this group does provide substantial levels of protection against COVID-19. This should bring welcome news to those who are at most risk across the country.

“However, caution is still needed. Restrictions continue to ease and case rates remain high, meaning that all people, especially those who are at most risk, should continue to take extra precautions until fully vaccinated with two doses.”

Co-author of the study, Professor Helen Colhoun of the Institute of Genetics and Cancer at University of Edinburgh, said:

“Through using a pre-existing register that had been used to determine the eligibility for the national shielding support programme, we were able to identify those with certain conditions or on certain drugs that were likely to lead to extreme vulnerability to COVID-19.

“We found that in most categories of vulnerability, the vaccine was highly effective in reducing the risk of severe COVID-19. However, for those who have received a solid organ transplant, there was not enough data to demonstrate the vaccine’s effect due a low number of people in this group, meaning further studies are needed.

“In the meantime, we would still encourage recipients of organ transplants to get fully vaccinated if they have not done so already.”

View the full 'Efficacy of COVID-19 vaccination in individuals designated as clinically extremely vulnerable in Scotland' report (external website)

Last updated: 28 July 2021