Intended for healthcare professionals

Letters Support for self-isolation

Covid-19: Self-isolation is the weakest link in stopping transmission

BMJ 2021; 372 doi: (Published 17 February 2021) Cite this as: BMJ 2021;372:n455
  1. Michael Gill, former regional director of public health
  1. London NW6 4DG, UK
  1. mgilm1{at}

At last the weakest link in the chain of covid-19 transmission—self-isolation—is getting the attention it deserves.1 Cevik and colleagues say that “risk of household transmission within crowded and otherwise inadequate housing intersects with financial barriers to isolation and inability to work from home.” In other words, given the practical difficulties associated with self-isolation in a confined space with shared facilities and several household members, the net effect of self-isolation across the population might be increased transmission. The new variant will have amplified that possibility. We know that at least 60-70% of transmission is within households, 10 times more than any other single route. This was also true outside lockdown periods.2

At current rates of community transmission, “managed isolation” (providing alternative accommodation for all cases) looks unfeasible. An alternative, which is no more than an extension of existing policy, is to make the unit of self-isolation not the individual but the household, so that all those living under the same roof as the case self-isolate for 10 days or until the last household member has a negative test result, whichever is later. Financial compensation should be related to household size. A one-off early payment might be an incentive to all to maintain social distancing in the house. There could be a threshold for supplementary compensation in cases of extreme serial household infection. Other support, material and psychological, will be needed, especially when self-isolation stretches beyond the minimum 10 days.

At the very least, the Scientific Advisory Group for Emergencies should commission modelling of the current approach to estimate the size of the effect of different rates of self-isolation on overall transmission. We should do all we can to exclude the possibility that this key covid-19 control intervention has any unintended, or even regressive, effects.


  • Competing interests: None declared.

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