Precautionary breaks: Planned, limited duration circuit breaks to control the prevalence of SARS-CoV2 and the burden of COVID-19 disease

COVID-19 in the UK has been characterised by periods of exponential growth and decline, as different non-pharmaceutical interventions (NPIs) are brought into play. During the early uncontrolled phase of the outbreak(March 2020) there was a period of prolonged exponential growth with epidemiological observations such ashospitalisation doubling every 3-4 days. The enforcement of strict lockdown measures led to a noticeabledecline in all epidemic quantities that slowed during the summer as control measures were relaxed. FromAugust 2020, infections, hospitalisations and deaths began rising once more and various NPIs were appliedlocally throughout the UK in response.Controlling any rise in infection is a compromise between public health and societal costs, with morestringent NPIs reducing cases but damaging the economy and restricting freedoms. Typically, NPI impositionis made in response to the epidemiological state, are of indefinite length and are often imposed at shortnotice, greatly increasing the negative impact. An alternative approach is to consider planned, limited durationperiods of strict NPIs aiming to purposefully reduce prevalence before such emergency NPIs are required. These''precautionary breaks'' may offer a means of keeping control of the epidemic, while their fixed duration and theforewarning may limit their societal impact. Here, using simple analysis and age-structured models matched tothe UK SARS-CoV-2 epidemic, we investigate the action of precautionary breaks. In particular we consider theirimpact on the prevalence of SARS-CoV-2 infection, as well as the total number of predicted hospitalisationsand deaths caused by COVID-19 disease. We find that precautionary breaks provide the biggest gains whenthe growth rate is low, but offer a much needed brake on increasing infection when the growth rate is higher,potentially allowing other measures to regain control.