The National Burden of Influenza-Associated Respiratory Illness Across Levels of Severity in Egypt, 2016-2019.

Introduction: Influenza burden (IB) estimates are crucial for monitoring disease trends, allocating limited resources, and promoting influenza vaccination. However, IB in Egypt is poorly understood. This study estimates the mean-seasonal IB in Egypt, across levels of severity by age and regions using sentinel surveillance data between 2016 and 2019.

Methods: Influenza surveillance was implemented among patients hospitalized with severe acute respiratory infection (SARI) at eight sentinel hospitals across Egypt. We estimated the influenza-associated SARI hospitalization in two governorates and then extrapolated nationally using the World Health Organization (WHO)-recommended methods. Thereafter, we estimated IB-associated mild/moderate illness and deaths using IB pyramid tool developed by WHO and the John Hopkins Center for Health Security. Rates were reported per 100,000 population.

Results: The estimated mean seasonal number of influenza-associated mild/moderate illness, hospitalized noncritically and critically ill patients, and deaths was 16,425,938 (95% CI: 1,150,888-40,409,614), 30,335 (95% CI: 9971-670,288), 9110 (95% CI: 580-16,321), and 2660 (95% CI: 154-9908), respectively. The highest rate of influenza-associated mild/moderate illness was among aged 5-14 year (22,932; 95% CI: 825-25,546.3), whereas the highest rates of severe influenza were among aged > 65 years (hospitalizations: 159.4, 95% CI: 121.7-205.0; deaths: 56.0, 95% CI: 0.6-111.0). Children aged < 5 years also experience high rates of influenza-associated hospitalization (52.0, 95% CI: 43.0-62.0).

Conclusions: The WHO method estimated a high burden of severe influenza among aged ≥ 65 and aged < 5 years in Egypt. To reduce severe IB, increased influenza vaccine uptake together with enhanced immunization strategies implementations among the elderly and children are warranted.