Can laboratory-based surveillance help identify populations most at risk of invasive pneumococcal disease in South Africa?
Invasive pneumococcal disease (IPD), caused by Streptococcus pneumoniae, remains an important cause of illness and death in South Africa, particularly among young children, older adults, and immunocompromised individuals. Although the introduction of pneumococcal conjugate vaccines (PCVs) into the Expanded Programme on Immunisation has reduced disease incidence, IPD continues to occur, highlighting the need for ongoing surveillance.
Laboratory-based surveillance provides critical information on disease incidence, circulating serotypes, and populations at highest risk. These data help assess vaccine impact, monitor changes in pneumococcal epidemiology, and inform public health policy. Surveillance findings have also demonstrated important differences in disease burden between provinces, emphasising the value of local epidemiological analyses.
The following report describes the epidemiology of IPD in the Free State, KwaZulu-Natal, and Mpumalanga provinces from 2019 to 2024. We examine disease incidence, serotype distribution, and clinical characteristics to support targeted vaccination strategies and guide public health planning in South Africa.
Materials and Methods
Data were collected prospectively through GERMS-SA, a national infectious disease surveillance platform conducting laboratory- and population-based surveillance, supplemented by enhanced surveillance at selected sites. All methods for prospective and retrospective clinical data collection are standardised and have been described previously.
The FS, KZN, and MP provinces were selected for this report as part of a series of provincial-level descriptive analyses covering all nine provinces in SA, with each report providing data to support provincial public health planning. From 2019 through 2024, data were collected on laboratory-confirmed cases of IPD.
Results
Between January 2019 and December 2024, 1 710 laboratory-confirmed IPD cases were reported to the GERMS-SA surveillance programme in the Free State, KwaZulu-Natal, and Mpumalanga provinces. Just over half (51%; 869/1 710) of cases were confirmed by blood culture, and demographic characteristics were similar between all reported cases and those captured through enhanced surveillance sites.
The highest average annual IPD incidence was recorded in the Free State (2.3 per 100 000 population), followed by KwaZulu-Natal (1.3) and Mpumalanga (1.2). Infants aged younger than one year had the highest incidence rates in all three provinces, followed by adults aged 45–64 years.
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