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

To assess the potential effectiveness of RSV intervention strategies, understanding these transmission dynamics, including the basic reproduction number (R 0 ), the average number of secondary cases generated by a single primary case is important [14] . There are several different methods of estimating R 0 , but the 2 most commonly used methods involve R 0 calculation using (1) the case incidence data and (2) the generation time [14, 15] . The serial interval, which is almost equivalent to the generation time [16] , is defined as the duration between symptom onset of a primary case and symptom onset of a secondary case. R 0 depends on various factors, so it varies between epidemics associated with the same pathogen [17] . Several studies on RSV transmission dynamics, including R 0 , have been conducted to understand RSV seasonality [18, 19] . The variations of R 0 need to be defined to evaluate the effectiveness of control strategies [15] .