Effect of Baseline Dengue Serostatus Among Tetravalent Dengue Vaccine CYDTDV (Dengvaxia®) Recipients on Subsequent Virologically Confirmed Dengue in the Philippines

This is a cohort study that aims to determine the relative risk of developing virologically-confirmed dengue among Philippine children who are eligible to receive dengue vaccine during the DOH Mass Dengue Vaccination. Additionally, it also aims to determine the relative risk of developing severe and/or hospitalized virologically-confirmed dengue among Philippine children who received the Dengue vaccine, describe the epidemiologic trends and characteristics of virologically-confirmed dengue among these children, and assess the performance of simpler tests such as dried blood spots and serum IgG for the assessment of dengue seroprevalence at the population level. We will enroll children who are residents of selected areas in Region 7, Philippines. Children should be eligible to participate in the Department of Health mass dengue vaccination. They will be prospectively venipunctured for baseline dengue serologic status. The blood samples will be stored for serologic testing using neutralization tests and commercial IgG tests. Children in the cohort will be followed up, and those who present with <5 days of fever will be identified and blood drawn for dengue LAMP and RT-PCR.