Vaccination and Non-Pharmaceutical Interventions: When Can the UK Relax About COVID-19?

Background: The announcement of efficacious vaccine candidates against SARS-CoV-2 has been met with worldwide acclaim and relief. Many countries already have detailed plans for vaccine targeting based on minimising severe illness, death and healthcare burdens. Normally, relatively simple relationships between epidemiological parameters, vaccine efficacy and vaccine uptake predict the success of any immunisation programme. However, the dynamics of vaccination against SARS-CoV-2 is made more complex by age-dependent factors, changing levels of infection and the potential relaxation of non-pharmaceutical interventions (NPIs) as the perceived risk declines. Methods: In this study we use an age-structured mathematical model, matched to a range of epidemiological data, which also captures the roll-out of a two-dose vaccination programme targeted at specific age groups. Findings: We consider the interaction between the UK vaccination programme and future re- laxation (or removal) of NPIs. Our predictions highlight the population-level risks of early relaxation leading to a pronounced wave of infection, hospital admissions and deaths. Only vaccines that offer high transmission-blocking efficacy with high uptake in the general population allow relaxation of NPIs without a huge surge in deaths. Interpretation: While the novel vaccines against SARS-CoV-2 offer a potential exit strategy for this outbreak, this is highly contingent on the transmission blocking action of the vaccine and the population uptake, both of which need to be carefully monitored as vaccine programmes are rolled out in the UK and other countries.Funding Statement: This research was funded by the National Institute for Health Research (NIHR) [Policy Research Programme, Mathematical & Economic Modelling for Vaccination and Immunisation Evaluation, and Emergency Response; NIHR200411], the Medical Research Council through the COVID- 19 Rapid Response Rolling Call [grant number MR/V009761/1] and through the JUNIPER modelling consortium [grant number EP/V030477/1]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Declaration of Interests: All authors declare that they have no competing interests.Ethics Approval Statement: The data were supplied from the CHESS database after anonymisation under strict data protection protocols agreed between the University of Warwick and Public Health England. The ethics of the use of these data for these purposes was agreed by Public Health England with the Government’s SPI-M(O) / SAGE committees.