Is the government “following the data” on face coverings in schools?

A lack of robust mitigations in schools will contribute significantly to spread of B.1.617.2, say these authors

Boris Johnson, the UK prime minister has announced that face coverings will no longer be required in secondary school classrooms and communal areas from 17 May 2021, when the government begins Stage 3 of its lockdown easing roadmap. He continues to claim that he is  following “data not dates.” We are not so sure. 

On 4 May, we submitted an open letter to Gavin Williamson, the Secretary of State for Education, signed by over 80 scientists and public health professionals as well as major education unions and more than 1000 parents, students, and members of public. [1] We outlined:

  • Evidence showing how infections among children and in the community closely track school openings and closures, with rises in positivity among English school-age children, for example, prior to the Easter break and reduction over Easter; [2,3]
  • Evidence that parents of school children learning in-person at school are at higher risk of infection and hospitalisation compared to matched controls when strict mitigations are absent; [4,5]  
  • Evidence that masks are effective in reducing transmission within schools and into households; [5]
  • CDC and WHO recommendations, both supporting use of masks in schools [6,7]
  • The risk of long covid, with 10-13% of children developing persistent symptoms for five weeks or more and 7-8% for 12 weeks or more. An estimated 43,000 UK children and 114,000 teachers were living with long covid in the UK at the end of March 2021; [8]
  • The need for mitigations to protect the health of children, parents, teachers, and the wider community, and to ensure children can continue with in-person education free from disruption  from school closures and lockdowns if outbreaks occur; [3]
  • The risk posed by variant of concern outbreaks in schools, specifically the B.1.617.2 and B.1.351 variants, with outbreaks already reported in several schools; [9-12]
  • Countries like Israel where schools only opened after >80% of adults were fully vaccinated and still require masks in both primary and secondary schools.

The government response to our letter failed to address any of our points, but at the same time acknowledged that, “The available scientific evidence is that, when used correctly, wearing a face covering reduces the emission of virus-carrying particles when worn by an infected user, helping to protect others.” SAGE, which advises the government, also supports continued face coverings in schools after 17 May. [13] 

Since we sent our letter, the data have become even more concerning. Rapid growth of the B.1.617.2 variant, implicated in the rapid devastating growth of the pandemic in India and its neighbours, is now being identified across England, with cases unlinked to travel or surge testing doubling weekly, even as cases of B.1.1.7 have been declining. [14,15] This growth, despite current levels of vaccination and restrictions, raises grave concerns about what will happen when current restrictions are eased on 17 May. 

Alarmingly, 11% of all sequences from England and 25% overall in London (although much higher levels in some districts such as South Northamptonshire) were B.1.617.2 on 1 of May. [15] It now appears to be the dominant variant (>50%) in several local authorities, including Bolton, Sefton, Blackburn, and Bedford where exponential growth is now being observed. [15-17] These findings are consistent with this variant being more transmissible than B.1.1.7, which in turn is 40-70% more transmissible than previous variants. [18] Importantly, the effectiveness of current vaccines being deployed in the UK against the B.1.617.2 variant remains uncertain. A recent SAGE document states that “a variant of concern [VOC] that is as transmissible as B.1.1.7 but against which vaccines or prior infection yield less protection could easily lead to another peak of double or treble the size seen in Jan 2021 if no interventions are taken. A VOC with more substantial escape from immunity could be akin to an entirely new pandemic and would require re-imposition of significant restrictions in order for NHS pressures to remain manageable.” [19]

Several outbreaks of the B.1.617.2 variant have already been reported in schools, including secondary schools, and have potentially contributed to spread within the community. [9-11,17,20] However, despite these alarming developments, the government has continued to pursue a pre-specified timetable for easing restrictionsfollowing dates not data. Public Health England was reported to have delayed release of key data on spread of B.1.617.2 until after recent elections, appears to have misrepresented evidence on the impact of school openings on infection rates on media (with the Office of Statistics Regulation asking it to correct the record), and has not released aggregate data on number of cases of B.1.617.2 linked to schools, despite repeated calls for this by unions. [20-23] This does not engender trust.

We believe there is a very real risk that lack of robust mitigations in schools will contribute significantly to spread of B.1.617.2, and lead to significant increases in transmission as the new variant gains dominance. Given its espoused commitment to “data not dates”, the government should a) urgently release data on cases of B.1.617.2 linked with school outbreaks; b) retain facemasks in secondary schools until the data show that the risk of transmission is minimal; and c) make public the evidence that PHE has relied on in deciding to remove recommendations for mask use among children in schools. Transparency is vital to restoring public trust. 

Deepti Gurdasani, senior lecturer in machine learning, Queen Mary University of London.

Christina Pagel, professor of operational research (branch of applied mathematics), director of the Clinical Operational Research Unit & co-director of the UCL CHIMERA hub, University College London. Member of Independent SAGE. 

Kit Yates, senior lecturer in the Department of Mathematical Sciences and co-director of the Centre for Mathematical Biology at the University of Bath. Member of Independent SAGE. 

Martin McKee, professor of European public health at the London School of Hygiene and Tropical Medicine. Member of Independent SAGE. 

Trish Greenhalgh, Professor of primary care health sciences, University of Oxford, UK.

Competing interests: none declared

Acknowledgements: We would like to acknowledge contributions of Susan Michie and Stephen Reicher and Hisham Ziauddeen, who commented on and improved this manuscript. 


  1. Open letter to Secretary of State for Education regarding the need to continue wearing face coverings as a mitigatory measure against SARS-CoV-2 in schools. 2021.
  2. Office for National Statistics. Coronavirus (COVID-19) Infection Survey, UK: 23 April 2021.
  3. Gurdasani D, Alwan NA, Greenhalgh T, et al. School reopening without robust COVID-19 mitigation risks accelerating the pandemic. Lancet 2021; 397(10280): 1177-8.
  4. Forbes H, Morton CE, Bacon S, et al. Association between living with children and outcomes from covid-19: OpenSAFELY cohort study of 12 million adults in England. BMJ 2021; 372: n628.
  5. Lessler J, Grabowski MK, Grantz KH, et al. Household COVID-19 risk and in-person schooling. Science 2021.
  6. Centers for Disease Control. Schools and Child Care Programs​: Plan, Prepare, and Respond. Apr. 5, 2021. (accessed 26th April 2021.
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  13. Sample I QB, Adams R. Pupils should keep wearing masks into the summer, Sage told ministers. 2021.
  14. England PH. SARS-CoV-2 variants of concern and variants under investigation in England: Technical briefing 10, 2021.
  16. Campbell DI. In: @Ian_Campbell_, editor. The spikes in reported cases in #Bolton and in #Blackburn with Darwen have continued. The total daily cases in North-West England is now at a 4-week high. The Government’s plan to “live with the virus” is not a viable one: Twitter; 2021.
  17. McKeon C. ‘Complacency’ warning given to Sefton people as covid cases have doubled in a week. ECHO News; 2021. p.
  18. Volz E MS, Chand M, Barrett JC, Johnson R, Geidelberg L. Transmission of SARS-CoV-2 Lineage B.1.1.7 in England: Insights from linking epidemiological and genetic data. . MedRxiv 2021.
  19. SPI-M-O. SPI-M-O: Summary of further modelling of easing restrictions – Roadmap Step 3, 2021.
  20. Indian Covid ‘variant of concern’ found in education settings in Bedford. Bedfordshire Live News. 2021.
  21. England PH. In: @PHE_uk, editor. The latest round of our Schools Infection Survey (SIS) suggests a reduction in the percentage of secondary school pupils and staff testing positive for #COVID19 since schools reopened. Read more: https://bitly/2SpjaUZ  @ONS; 2021.
  22. Gurdasani D. @dgurdasani1. Twitter.
  23. Unison in Schools. Face Coverings in Schools. In: @UNISONinSchools, editor. Face Coverings – UNISON has once again asked Government if they will share the ‘aggregated’ data on new variants cases linked to schools They have committed to respond today: Twitter; 2021.