Transmission of Respiratory Syncytial Virus Among Children Under 5 Years in Households of Rural Communities, the Philippines

Otomaru, Hirono; Kamigaki, Taro; Tamaki, Raita; Okamoto, Michiko; Alday, Portia Parian; Tan, Alvin Gue; Manalo, Joanna Ina; Segubre-Mercado, Edelwisa; Inobaya, Marianette Tawat; Tallo, Veronica; Lupisan, Socorro; Oshitani, Hitoshi

This study was conducted in Biliran Province, a rural territory in the Eastern Visayas region in central-eastern Philippines (Supplementary Figure 1) . The territory comprises 1 main island and several small islands and has 8 municipalities. We conducted a community-based prospective cohort study in 2 municipalities, Caibiran and Kawayan, from March 2014 to June 2016. Children <5 years old were identified through household visits and were invited to participate in the study. We enrolled 2348 households with 4012 children as cohort participants. We asked the caregivers of these children to record respiratory symptoms including cough, coryza, difficulty in breathing, wheezing, chest indrawing, and fever every day. Nurses conducted biweekly household visits to check these written records. We collected nasopharyngeal swabs (NPSs) from children who developed fever and either cough or difficulty in breathing within 7 days from household visit onset. In addition, when children with respiratory symptoms such as cough, difficulty in breathing, or coryza visited health facilities, we collected NPSs. The health facilities were the Biliran Provincial Hospital, Naval (capital of Biliran Province), a secondary-level referral and the only hospital in Biliran Province, and rural health units of Caibiran and Kawayan, where qualified doctors provide outpatient care. The specimens were stored in a viral transport medium at 4°C and transported with an ice pack to the Research Institute for Tropical Medicine (RITM) in Manila for laboratory work. This study was approved by the institutional review board of the RITM (2008-05-10, 2013-2) and ethics committee of the Tohoku University School of Medicine, Miyagi, Japan (2012-1-5, 2012-1-63).