The respiratory syncytial virus (RSV) infects cells along the human respiratory tract, from the nose to the lungs. Each year globally RSV causes over 3.6 million hospitalizations and about 100 000 deaths in children under 5 years of age. Since 2017, Mongolia has participated in a WHO RSV surveillance project. From 2024 onwards, this surveillance was enhanced, with the aim to understand the incidence and risk factors of severe RSV infections, with technical support from WHO and partners. This article describes six training sessions for sentinel site staff that were held in October 2024, on surveillance practices.
RSV is a common respiratory pathogen that causes a wide spectrum of disease, ranging from mild upper respiratory tract infections (in most cases) to lower respiratory tract infections, which can be life threatening. Young children, especially those under six months of age, are at the highest risk of severe RSV-associated hospitalizations and deaths. Most RSV-associated paediatric RSV deaths (97%) occur in low- and middle-income countries (LMICs) where there is limited access to supportive medical care. More information can be found in the WHO RSV factsheet.
Between 2016 and 2018, WHO piloted Phase 1 of an RSV surveillance project based on the Global Influenza Surveillance and Response System (GISRS) network in 14 countries. The project expanded to include another 11 countries in 2019. Mongolia participated in Phase 1, and the preliminary data revealed RSV was the main virus detected among hospitalized children aged under 5 years. An enhanced RSV surveillance aiming to estimate four levels of disease burden, including incidence of RSV-associated hospitaizations among children aged under 2 years in Mongolia, was planned in 2024 with technical support from WHO and partners.
The first two sessions included over 40 participants, including deputy heads of clinical management, doctors, nurses and epidemiologists from the sentinel units. During these sessions, participants were introduced to the enhanced RSV surveillance projects, the objectives, data collection, sample collection and storage, and data analyses. Participants discussed the application of extended Severe Acute Respiratory Infections case definitions and data collection forms. During the trainings, participants also provided valuable feedback on surveillance protocol revision. The subsequent four sessions were held at the respective sentinel units, targeting health-care workers and specialists who had not attended the initial training sessions, ensuring broader participation and understanding of the surveillance practices.
This enhanced RSV surveillance project was launched in January 2025 and will continue throughout the year. The Mongolia National Center for Communicable Diseases has been conducting intensive monitoring and supervision to the four sites since launching of the surveillance to ensure adherence to practices outlined in the surveillance protocol. The estimations of RSV-associated disease burden are expected before 2027. Results from this surveillance will lay evidence for the introduction of RSV prophylaxis products in Mongolia. WHO will continue supporting this process.