Since the start of the influenza season in week 17 (week starting 22 April 2024), there has been a steady increase in the number of influenza cases from the pneumonia (hospitalised cases) surveillance sentinel sites. Based on the circulation of influenza in 2016-2019 and 2022-2023, the 2024 flu season transmission and impact are at a moderate level. As of 26 May 2024, among patients enrolled in the Pneumonia Surveillance Programme, the most commonly detected subtype and lineage is influenza A(H1N1)pdm09 (90/116, 77.6%) followed by influenza B/Victoria (23/116, 19.8%) and influenza A(H3N2) (3/116, 2.6%).
Influenza detection rates from week 17 to week 21 in 2024, in the Pneumonia Surveillance Programme, exceeded the average detection rates during the same weeks in previous seasons (2016-2019; 2022). However, it follows a similar trend compared to the 2023 influenza season. Similarly, the proportion of inpatient admissions and outpatient clinic consultations from a private hospital group and a network of general practitioners that are respiratory-related (based on ICD-10 codes, J00-J99) appears to be at a similar level to the peak in 2023. Clinicians should include influenza as a possible diagnosis when managing patients with respiratory illness.
Although the majority of people with influenza will present with mild illness, influenza may cause severe illness, which may require hospitalisation or cause death, especially in individuals who are at risk of getting severe influenza complications. High-risk groups include pregnant women (up to 6 weeks post-partum), individuals living with HIV, those with chronic conditions such as diabetes, lung disease, tuberculosis, heart disease, renal disease, and obesity, older individuals (≥aged 65) and children <2 years old. These groups should be encouraged to seek medical help early.
