EpidemicsOdds and Evens: A Strategy for Safely Exiting Lockdown 2
Should lockdowns be reimposed, and, if so, for how long? A key difficulty for governments in finding the right answer is that they do not know with any certainty how transmission rates might increase if restrictions are removed. Based on our research, we believe there is a case for a cyclic lockdown policy, which could help control the spread of COVID-19 and also provide evidence to help predict the future much better.
As the Danish physicist Niels Bohr once warned, it is difficult to make predictions, especially about the future. This warning is particularly true when it comes to the epidemiology of COVID-19. In the past week, we have learned that cases in the UK have exceeded even the worst-case scenario predicted a few months ago by SAGE, the government’s expert advisory group.
The UK and many other countries in Europe are in lockdown again, but what should be done next? While most countries are planning lockdowns of up to a month, we know from the first wave that this may not be long enough to suppress COVID-19 to manageable levels. However, we also know that prolonged lockdowns come at a heavy price, including:
• Economic costs: the International Monetary Fund (IMF) estimates that in 2020 GDP across Europe will fall by almost 8%.
• Impacts on other aspects of health, such as mental health.
A key difficulty for governments is that they do not know with any certainty how transmission rates might increase if restrictions are removed. Based on our research, we believe there is a case for a cyclic lockdown policy, which could help control the spread of COVID-19 and also provide evidence to help predict the future much better.
While there has been a deluge of COVID-19 research, when it comes to understanding community transmission it is often hard to isolate the effect of individual social distancing policies on the spread of COVID-19. Take the recent rise in COVID-19 cases, how much is due to resumption of schools and universities versus changes in weather?
A better approach is to build a controlled experiment into policy to allow rapid evaluation. This approach was used in California during the 1918 influenza pandemic to evaluate the effectiveness of wearing masks. A policy that enforced the wearing of masks in San Francisco was evaluated by comparing rates of influenza to a control city of Oakland that did not enforce this policy.
More than 100 years later, in contrast to the thousands of randomized controlled trials investigating ways to treat COVID-19 with drugs, there are almost no controlled experiments assessing social distancing policies. As a recent review concluded: “The imbalance … is worrying, in particular the paucity of trials on non-drug interventions. Despite non-drug interventions being the mainstay of current mitigation, [there are] none examining social distancing, quarantine effect or adherence, hand hygiene, or other non-drug interventions.”
