Managing individual and population risk from covid-19

What is the advice?

For people aged over 60 or who have underlying cardiovascular or respiratory disease or diabetes, the World Health Organization emphasises social distancing advice similar to that which already applies to the entire population of many countries.2 In the US, people aged over 65, residents of nursing homes, and those with certain chronic conditions have been advised to take (unspecified) “extra precautions”3 in applying population-wide public health messages. Some European countries have issued additional social distancing guidance which applies to all older people and those with chronic conditions.45

Advice from the chief medical officers of the UK has been more complex, with separate guidance targeted at two categories of people deemed to be at greater risk than the wider population. Those at moderate risk or “clinically vulnerable” broadly constitute people aged over 70, pregnant women, and those who have conditions for which influenza vaccination is recommended.6 The moderate risk group is advised to be “particularly stringent” in adhering to the hygiene and social distancing measures recommended for everyone.7

A further high risk (“clinically extremely vulnerable”) cohort has been identified, numbering around two million in England.68 It includes recipients of solid organ transplants, some cancer patients, those with severe respiratory disease (cystic fibrosis and severe chronic obstructive pulmonary disease or asthma), patients with disorders that increase risk of infection (such as homozygous sickle cell disease), people who receive some immunosuppressive treatments, and pregnant women with serious heart disease.9 People in this group are currently advised to “shield,” meaning that they should avoid leaving their homes.10

Confused communication

People in the high risk group have been identified centrally by using primary and secondary care datasets.6 Many people have been placed in this group erroneously and received letters advising them to shield.8 Some of those who were advised to shield have subsequently been informed by text message that they are no longer required to do so, leaving them uncertain as to what advice they should follow.11 Separate briefings to clinicians have advised that additional groups, such as patients on renal dialysis or those with a history of splenectomy, should also shield, although these categories are yet to be added to the government’s website.1213

Headlines calling on the government to “set free” healthy over-70s seems to reflect a widespread misunderstanding about who shielding advice applies to.14 Underlining just how confusing the official terminology is, the secretary of state for health, Matt Hancock, seemed to mix up the risk categories himself when condemning this coverage as misleading.15 Many people are unsure whether they have been advised to shield or may be shielding unnecessarily. Interpreting advice is particularly challenging for vulnerable population groups who may not speak English as a first language or lack access to reliable sources of information.

Uncertain evidence

In the absence of a mature evidence base the chief medical officers’ advice is drawn from expert consensus.716 Since March, evidence has emerged suggesting that people from ethnic minority backgrounds are disproportionately affected by covid-19.1718 The Royal College of Obstetricians and Gynaecologists considers that pregnant women with no pre-existing medical problems are not at any additional risk.19 Initial findings from the UK Obstetric Surveillance System suggest that women who are overweight or obese, older than 35, from ethnic minority backgrounds, or with conditions such as hypertension and diabetes were at greater risk of developing serious illness.20 Most pregnant women admitted to hospital with covid-19 have been in their third trimester, supporting guidance for women to take particular care from 28 weeks.19

The prolonged confinement endured by the millions who are shielding is likely to come with substantial costs to quality of life and could cause lasting impairments to physical and mental wellbeing. Decisions on shielding should be informed by individuals’ values and priorities. NHS correspondence that refers to people “being shielded” rather than who “are shielding” understates the autonomy of individuals in choosing how they wish to reduce their risk of infection. Many will make an entirely appropriate judgment that their best interests are served by continuing to venture outdoors, in accordance with the same social distancing restrictions that apply to the rest of the population. Care should be taken by health professionals and officials to respect such decisions and to be explicit about the uncertainties underpinning national guidance.

Achieving a partnership with those who we believe are at increased risk from covid-19 to help them to reduce their risk requires clear and consistent communication, openness about uncertainty, and respect for personal autonomy.