Intended for healthcare professionals

Letters Stratification of shielding

Is stratified shielding from covid-19 feasible and ethical?

BMJ 2020; 370 doi: (Published 07 July 2020) Cite this as: BMJ 2020;370:m2660
  1. Irene Petersen, professor of epidemiology and health informatics
  1. Department of Primary Care and Population Health, Institute of Epidemiology and Health Care, University College London, London, UK
  1. i.petersen{at}

The concept of stratified shielding from covid-19 is interesting but complex and potentially unethical to implement in practice. As described by Davey Smith and Spiegelhalter,1 the risk of covid-19 mortality can be described as a two step process: the risk of getting infected and the risk of dying after infection.

In theory, it would be relatively straightforward to derive a risk prediction tool to identify the people most at risk of dying after being infected with covid-19. Other risk prediction tools have successfully been implemented in UK clinical practice, such as those to identify people eligible for preventive cardiovascular treatments. The question is whether it would be feasible and ethical to implement risk prediction tools in the context of covid-19.

First, the risk prediction tool would probably identify many people at high risk who are unable to shield for a long period of time owing to work and family commitments. Is it ethical to offer a risk score to someone who is unable to modify their risk? Second, we should consider the ethical implication of shielding or isolation for an extended period of time.

Finally, is shielding effective when the prevalence of covid-19 in the local community is high? We have so far failed to shield some of the people who needed it the most, such as people living in care homes.

The idea of stratified shielding looks compelling on paper, but perhaps the authors would reconsider the proposal if they were in the high risk group and eligible for shielding.


  • Competing interests: None declared.

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