Study Population
A detailed report on the methods and protocol used for the Nicaraguan Pediatric Influenza Cohort (NPICS) has been described previously20,21. Briefly, the primary aim of the NPICS study is to assess the burden, incidence, and seasonality of influenza in Nicaragua. However, while most infectious disease studies focus on a single pathogen or syndrome, NPICS was developed with the goal of assessing multiple respiratory pathogens and can test stored samples for additional pathogens. The NPICS study is an ongoing prospective cohort study initiated in 2011 and includes children aged 0­–14 years, residing in District II in Managua, Nicaragua. Legal guardians are encouraged to bring their children to the Health Center Sócrates Flores Vias (HCSFV), at the first sign of illness and receive free medical care and are thus incentivized to use this health outpost as opposed to seeking care at other medical clinics. Initial enrollment for the cohort study was conducted in 2011 by randomly sampling children aged 3–11 years who were enrolled in a previous cohort study for influenza within District II, and additional children aged 0-2 were recruited through house-to-house visits within the catchment area. The age distribution of the NPICS cohort is representative of children of Nicaragua20 and spatially representative of district II in Managua20. Additional children aged 0­–2 years were recruited from houses throughout the study catchment area. Children ≤ 4 weeks old are enrolled monthly into NPICS and age out of the study on their 15th birthday. In this study, we assess those enrolled in NPICS from 2011­–2016.