Integrated sentinel surveillance of influenza, SARS-CoV-2, RSV and respiratory viruses in Serbia

Abstract Introduction Integrated sentinel SARI surveillance of influenza, SARS -CoV-2 and RSV has been established in Serbia since 2021-2022 influenza season. Nine sentinel hospitals in 3 cities participated in the SARI surveillance system. The aim of this study is to provide a review of integrated sentinel surveillance of SARI in Serbia in 2023-2024 influenza season, from October 2023 to April 2024. Methods On a weekly basis, both epidemiological and virological data were collected. Surveillance is be conducted year-round. Specimens were tested for influenza, SARS-CoV-2,RSV and other respiratory viruses. Respiratory disease wards, intensive care units (ICUs) and pediatric wards were all represented. Real time polymerase chain reaction (RT-PCR) was used. Results From October 2023 to April 2024, a total of 1571 SARI cases were reported with 100% recorded age. Of these, 35% were 0-4 years old, 16% were 5-14, 6% were 15-29, 14% were 30-64, 18% were 65-79 and 11% were 80+. Among these cases, 1002 (64%) respiratory specimens were collected. The number of positive samples for influenza was 294 (29%). The positivity rate was 10% for SARS-CoV-2 and 19 % for RSV. The highest proportion of laboratory-confirmed influenza cases was 67% in week 04/2023. Then above 50% in week 05/2023 and 06/2023. Type A viruses was predominated, accounting for 97% of all influenza SARI detections. Activity was dominated by A(H3) with 42% positivity rate. Also, collected swabs were tested for rhinoviruses, positivity rate was 26%, for adenoviruses, 12%, for human metapneumovirus, 7% and for parainfluenza 3 viruses, 4%. Conclusions Sustaining and intensified effective integrated surveillance for influenza, SARS-CoV-2,RSV and other respiratory viruses in Serbia is the priority especially in the frame of International Health Regulations. In this way, we improve national capacity for preparedness and emergency response to national and cross-border public health threats. Key messages • Building and maintaining integrated respiratory surveillance that can rapidly integrate the surveillance of a new viruses is crucial. • Establishing well structured surveillance of severe acute respiratory infections, strengthening and expanding respiratory viral surveillance is one the base pillars preparation for future pandemics.