letter . 2021 Jun 9;93(10):5682–5686. doi: 10.1002/jmv.27119
© 2021 Wiley Periodicals LLC
This article is being made freely available through PubMed Central as part of the COVID-19 public health emergency response. It can be used for unrestricted research re-use and analysis in any form or by any means with acknowledgement of the original source, for the duration of the public health emergency.