The 2024 influenza season has started. The influenza season started in week 17 (week starting 22 April 2024) when the influenza detection rate (3-week moving average) from the NICD inpatient pneumonia sentinel surveillance in public hospitals breached the seasonal threshold and remained above the threshold for two consecutive weeks (Figure 1). As of the 9 May 2024 within the pneumonia surveillance programme, the most commonly detected subtype and lineage is influenza A(H1N1)pdm09 (29/52, 55.8%) followed by influenza B/Victoria (7/52, 13.5%) and influenza A(H3N2) (2/52, 3.8%). Of the 52 samples that tested positive for influenza, 1 sample (1.9%) had inconclusive influenza A subtyping result, 7 samples (13.5%) were pending influenza A subtyping results, 1 sample (1.9%) had inconclusive influenza B lineage result, 3 samples (5.8%) were pending influenza B lineage results and 2 samples (3.8%) tested positive for influenza A(H1N1)pdm09 and influenza B/Victoria (Figure 2).
Influenza A(H3N2), A(H1N1)pdm09 and influenza B are common seasonal influenza strains in humans. The majority of people with influenza will present with mild illness, usually resolving within 3-7 days. However, influenza may cause severe illness leading to hospitalisation or possibly death, especially among those who are at risk of severe influenza illness or complications. High-risk groups include pregnant women, 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. Updated guidelines on influenza diagnosis and management are available at: https://www.nicd.ac.za/wp-content/uploads/2023/05/Influenza-guidelines_-25April-2023-final.pdf
Influenza vaccination is recommended to protect against infection and severe illness. Ideally the influenza vaccine should be administered prior to the start of the influenza season because it takes about 2 weeks for antibodies to develop following vaccination. However, it is never too late to vaccinate. Individuals at risk for severe illness are strongly encouraged to seek the influenza vaccine from either a public health clinic or privately through general practitioners and pharmacies. Annual vaccination is needed as the influenza virus is constantly changing and immunity to the vaccine wanes with time. Receiving the vaccine can reduce visits to clinics or doctor’s offices, absenteeism from work and school due to influenza illness, as well as prevent influenza-related hospitalizations.
