Correction to: Nature Medicine https://doi.org/10.1038/s41591-020-0771-1, published online 27 January 2020.

In the version of this article initially published, the date (year) was incorrect (10 January 2010) in the penultimate sentence of the first paragraph of the third subsection (‘Why Africa should be prepared’). The correct date is 10 January 2020. The error has been corrected in the HTML and PDF versions of the article.