Coronavirus (COVID-19) advice for people on the Highest Risk List: evidence review

This report presents key evidence underpinning our advice to people on Scotland's highest risk (formerly shielding) list.


At the beginning of the COVID-19 pandemic in March 2020, the four Chief Medical Officers across the UK agreed a range of treatments and health conditions[1] which they believed, based on the limited evidence available at that point, would mean that people might be at higher risk of severe illness or death if they caught the virus. These people were asked to shield for a period of 18 weeks, until the end of July 2020.

This report reviews the evidence that has emerged during the past two years, with particular focus on the vaccination programme and how this is working to protect the majority of the 177,000 people on the Highest Risk List (HRL), formally known as the Shielding List.

Throughout the COVID-19 pandemic, I and a team of 30 medical specialists have reviewed new research, data and insight from clinicians and scientists as it has emerged. This evidence has underpinned the advice we have provided to people on the Highest Risk List.

There has, rightly, been much interest in the Scottish Government's strategy of shielding, which had a major and lasting impact on people's lives. We asked all those at highest risk to strictly self-isolate for 12 weeks. We know how hard that was, and we know how frightening this past two years has been for many people.

Our strategy at the beginning was entirely focused on saving lives and protecting people at highest risk. There was very little data about COVID-19 risk factors at that point. Shielding was introduced as one of the few interventions available to us.

I have high confidence that the approach we took did protect people from catching COVID-19. Whilst it's difficult to quantify, as we don't know what would have happened had we not asked people to shield, it is a reasonable and logical conclusion that shielding saved lives.

However, we also know that asking people to isolate away from friends, family and society in general had a negative and lasting impact on people psychologically and socially. The rollout of the vaccine programme has changed the context significantly. The evidence on the effectiveness of vaccines for people on the Highest Risk List, coupled with the availability and efficacy of new treatments such as antivirals, immune modulators and monoclonal antibodies, has allowed us to take a different approach.

There is now, two years on, a far better understanding of the range of risk factors that may put someone at increased risk of becoming seriously unwell from COVID-19. This report sets out the strong base of evidence which shows that the COVID-19 vaccine is offering significant protection and preventing people on the Highest Risk List from becoming severely ill. Furthermore, death rates as a result of COVID-19 amongst people on the Highest Risk List have significantly reduced and there is now a far better understanding of the impact of COVID-19 on those with specific clinical conditions.

Whilst there are people who do have a higher risk from COVID-19 even following vaccination – primarily people whose immune systems are suppressed or compromised due to a health condition or treatment - the evidence set out in this paper clearly points to the reduced clinical risk for the majority of people on the Highest Risk List. This clear evidence underpins our decision to end the Highest Risk List at the end of May 2022 in Scotland.

Scotland's Chief Medical Officer will write to everyone on the Highest Risk List in the coming weeks to explain this decision, and to set out the identification process the NHS will retain to be able to quickly identify people who should be prioritised for vaccination, treatments and, if the threat level increases, for additional protective advice. In the meantime, we are asking people who have been on the Highest Risk List to follow the same advice in relation to COVID-19 as the rest of the population, unless advised otherwise by their GP and clinician, who know them and their specific health condition best.

Dr John Harden
Deputy National Clinical Director, Clinical Advisor for the Highest Risk List

Scottish Government



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