The authors are grateful for comments from D. Limmathurotsakul, S. Wongpalee, A. Wangwiwatsin, P. Subsoontorn, W. Piyaphanee and J. Prachumsri. C.C. was funded by the Wellcome International Intermediate Fellowship (216457/Z/19/Z), Sanger International Fellowship and the University of Oxford Nuffield Department of Medicine Career Development Scheme.