Government of the United States of America - Centers for Disease Control and Prevention (CDC), University of St Andrews, Government of the United States of America - Influenza Division, affiliation not provided to SSRN, Government of Kenya - Kenya Ministry of Health, Government of Kenya - Kenya Ministry of Health, Government of Kenya - Kenya Ministry of Health, Government of Kenya - Kenya Ministry of Health, Government of Kenya - Kenya Ministry of Health, Government of Kenya - Kenya Ministry of Health, Government of Kenya - Kenya Ministry of Health, Government of Kenya - Kenya Ministry of Health, Government of Kenya - Kenya Ministry of Health, Government of Kenya - Kenya Ministry of Health, Government of Kenya - Kenya Ministry of Health, Washington State University - Global Health Kenya, Kenya Medical Research Institute (KEMRI), Government of Kenya - Kenya Ministry of Health, Government of Kenya - Kenya Ministry of Health, Government of Kenya - Kenya Ministry of Health, Government of Kenya - Kenya Ministry of Health, Government of Kenya - Kenya Ministry of Health, Washington State University - Paul G. Allen School of Global Health, Government of the United States of America - Centers for Disease Control and Prevention (CDC), Washington State University - Global Health Kenya, Government of Kenya - Kenya Ministry of Health and Washington State University - Global Health Kenya