Published time: 27 April 2020
Authors: Daniel M Altmann, Daniel C Douek, Rosemary J Boyton
About a third of the world is under lockdown as a public health measure to curb the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19). Policy makers are increasingly pressed to articulate their rationales and strategies for moving out of lockdown; the process of re-emergence is already cautiously starting in Austria, Switzerland, Denmark, Wuhan, and some US states. As the counterpoise between further disease spread and socioeconomic costs is debated, it is essential that policy makers in all affected countries have the best possible data and understanding to inform any course of action.
Strategies in various countries that aim to stagger return to work on the basis of disease severity risk and age do not take account of how exposing even lower-risk individuals, such as young people with no comorbidities, to the virus so as to increase herd immunity can still result in the pandemic spread. The only selective pressure on SARS-CoV-2 is transmission—stop transmission and you stop the virus. The linchpin for a strategy to move out of lockdown seemingly rests on increased testing and contact tracing, possible return-to-work permits based on immune status repurposed or new therapeutics and, finally, vaccination. This approach is broadly sensible, yet immunology is a complex branch of molecular medicine and policy makers need to be alerted to important aspects of immunology in relation to COVID-19. There is no certainty as to the immunological correlates of antiviral protection or the proportion of the population who must attain them, making it impossible to identify a point when this level of immunity has been reached.
What policy makers need to know about COVID-19