If there has been coronavirus spread within schools, between year groups, would it not make sense to close entire schools to prevent further transmission within communities?

First published in November 2020.

This has been a topic of debate from early on.

It is clear that closing schools and other educational institutions is one of the most effective interventions in preventing Covid-19 transmission.

On the other hand, there are concerns about the harms done by closing schools – pupils missing out on education and on the benefits of social mixing, and in particular the exacerbation of inequalities, as more deprived children are likely to benefit more from school than less deprived children – they are less likely to have easy access to computers, wifi, etc., for example.

All of which does somewhat beg the question – could we not do more to support learning without sending children to overcrowded schools?

Some countries have opted for rotas: children in parts of Germany, for example, went to school in alternate weeks, so the school was only half as full as normal (allowing more space). If there are good distance learning systems in place, I can imagine children (other than the children of key workers and vulnerable children) attending one day a week, so there is much more space available.

The government’s “contain” framework describes four tiers of “closure”.

The extent to which schools are open could, logically, relate to the risk in the community in which the schools find themselves.

The Covid risk, as I have discussed before, is primarily related to the number of cases per unit population in the community. As there is invariably a lag in reporting cases, it may be reasonable to increase the risk if the numbers are rising sharply, and possibly to decrease the risk if they are falling. It may also be appropriate to discount cases known to be associated with a particular exposure (e.g. cases in a meat processing plant), where all of the cases and contacts have been identified, are isolating, and are thus not contributing to the general community risk.

Above a threshold – which I would like to see explicitly agreed and published – it might be appropriate to close schoolstier 4 of the contain framework (under which the children of key workers and vulnerable children continue to attend school).


  • [Possible] cases have to self-isolate until ten days after the onset of symptoms (or, if asymptomatic, of the date of the test), or until the diagnosis of Covid-19 has been “ruled out”. (Remember, the tests are not very sensitive; but when case levels are low, a negative Covid-19 test may be a reasonable indication of an alternative diagnosis.)
  • Contacts of possible cases have to self-isolate until 14 days (the possible incubation period), to ensure they don’t develop the disease and become infectious.

All of the schools I’ve spoken to have said that they are generally confident in their ability to provide the curriculum – to teach – if the majority of the students are attending the school; and they are also confident to do this if the majority of the students are doing remote learning. (Indeed, if they have staff self-isolating, they may be better able to continue working from home if they are teaching remotely anyway.)

But what is difficult, they tell me, is:

  • Trying to teach all the students if substantial numbers are self-isolating, and substantial numbers are in the school. (This is partly why closure makes sense if ≥1/3 students in a class or year group are self-isolating.)
  • They have to constantly – and with little or no notice – provide remote education for large numbers of pupils. This can be a reason for not trying to return to face to face teaching too quickly – it can be very disruptive if staff and students then have to isolate again.

My rule of thumb

When there are cases in particular schools (and I have dealt with quite a number of these now), I’ve adopted a rule of thumb…

  • If ≥1/3 students in a class or year group are self-isolating (as cases or contacts), the whole of the class or year group should close (tier 3 of the contain framework – vulnerable children and children of key workers continue to attend).
  • If a significant number of year groups are closed, the whole school should close (tier 4 of the contain framework – vulnerable children and children of key workers continue to attend). The precise number would depend on the size of the school (the number of year groups) – in a school with seven year groups, I’d generally recommend closing the school if three or more year groups were closed; in a school with only four year groups, one or two year groups might be sufficient.

If there is reason to suspect that there has been spread within the school, between year groups, that would lean more heavily towards closing the whole school.

  • Don’t forget the staffing and operational issues. If there are difficulties with staffing, because of the number of staff having to self-isolate or – as has been the case in some schools – unwell because they are taking a long time to recover from Covid-19, that would also push towards closing the school.

Other issues to consider include how good the school’s plans and ability to provide remote learning, and the ease (or otherwise) with which they can increase Covid risk mitigation – for example, if some parts of the school are very difficult to ventilate.🔷


  1. Department of Health and Social Care. COVID-19 contain framework: a guide for local decision-makers. Containing and managing local coronavirus (COVID-19) outbreaks, 2020; Updated 28 Aug 2020; Accessed: 2020 (30 Oct).
  2. Haug N, Geyrhofer L, Londei A, Dervic E, Desvars-Larrive A, Loreto V, et al. Ranking the effectiveness of worldwide COVID-19 government interventions. Nature Human Behaviour 2020, DOI: 10.1038/s41562-020-01009-0.
  3. Brauner JM, Mindermann S, Sharma M, Johnston D, Salvatier J, Gavenčiak T, et al. The effectiveness of eight nonpharmaceutical interventions against COVID-19 in 41 countries. medRxiv 2020:2020.05.28.20116129, DOI: 10.1101/2020.05.28.20116129.
  4. Bo Y, Guo C, Lin C, Zeng Y, Li HB, Zhang Y, et al. Effectiveness of non-pharmaceutical interventions on COVID-19 transmission in 190 countries from 23 January to 13 April 2020. Int J Infect Dis 2020, DOI: 10.1016/j.ijid.2020.10.066.

Dr Peter English, Public Health Doctor. Particular interests in vaccination and health intelligence.

[This piece was originally published in Peter English's random musings blog and re-published in PMP Magazine on 25 November 2020, with the author’s consent. | The author writes in a personal capacity.]

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