- Correspondence to Dr Denton Callander, Department of Epidemiology, Columbia University, New York, NY 10027, USA;
- Received April 16, 2020
- Revised May 26, 2020
- Accepted June 8, 2020
- First published June 26, 2020.
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.