medRxiv preprint doi: https://doi.org/10.1101/2021.02.07.21251287; this version posted July 22, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license .

Modelling the impact of reopening schools in the UK in early 2021 in the presence of the alpha variant and with roll-out of vaccination against SARS-CoV-2

J.Panovska-Griffiths1,2,3*, R.M. Stuart4,5, C.C. Kerr6,7, K. Rosenfield6, D. Mistry6, W. Waites8,9, D.J. Klein6, C. Bonell10$, R.M.Viner11$

1 Big Data Institute, Nuffield Department of Medicine, Oxford, UK 2 The Queen’s College, Oxford University, Oxford, UK 3 The Wolfson Centre for Mathematical Biology, University of Oxford, Oxford, UK 4 Disease Elimination Program, Burnet Institute, Melbourne, VIC, Australia 5 Department of Mathematical Sciences, University of Copenhagen, Copenhagen, Denmark 6 Institute for Disease Modeling, Global Health Division, Bill & Melinda Gates Foundation, Seattle, USA 7 School of Physics, University of Sydney, Sydney, NSW, Australia 8 School of Informatics, University of Edinburgh, UK 9 Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, Keppel St, London, UK 10 Faculty of Public Health and Policy, London School of Hygiene and Tropical Medicine, London, UK 11 UCL Great Ormond St. Institute of Child Health, London, UK

$ These authors contributed equally *Corresponding author: [email protected]

Background Following the resurgence of the COVID-19 epidemic in the UK in late 2020 and the emergence of the alpha (also known as B117) variant of the SARS-CoV-2 virus, a third national lockdown was imposed from January 4, 2021. Following the decline of COVID-19 cases over the remainder of January 2021, the question of when and how to reopen schools became an increasingly pressing one in early 2021. This study models the impact of a partial national lockdown with measures enacted in communities and workplaces under different strategies of reopening schools from March 8, 2021 and compares it to the impact of continual full national lockdown remaining until April 19, 2021.

Methods We used our previously published agent-based model, Covasim, to model the emergence of the alpha variant over September 1, 2020 to January 31, 2021 in presence of Test, Trace and Isolate (TTI) strategies. We extended the model to incorporate the impacts of the roll-out of a two-dose vaccine against COVID-19, with 200,000 daily vaccine doses prioritised by age starting with people 75 years or older, assuming vaccination offers a 95% reduction in disease acquisition risk and a 30% reduction in transmission risk. We used the model, calibrated until January 25, 2021, to simulate the impact of a full national lockdown (FNL) with schools closed until April 19, 2021 versus four different partial national lockdown (PNL) scenarios with different elements of schooling open: 1) staggered PNL with primary schools and exam-entry years (years 11 and 13) returning on March 8, 2021 and the rest of the schools years on March 15, 2020; 2) full-return PNL with both primary and secondary schools returning on March 8, 2021;NOTE: This 3) preprintprimary reports-only new PNLresearch with that has primary not been certifiedschools by peerand review exam and criticalshould not yearsbe used (toyears guide clinical 11 and practice. 13)

1 medRxiv preprint doi: https://doi.org/10.1101/2021.02.07.21251287; this version posted July 22, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license .

going back only on March 8, 2021 with the rest of the secondary schools back on April 19, 2021