Issued by the National Institute for Communicable Diseases based on laboratory testing data
Highlights
- The NICD has tested 5853 serum samples for measles since epidemiological week 40, 2022, of which 976 (17%) were confirmed positive. In outbreak-affected provinces, 970 cases have been reported since week 40, 2022. In the past weeks (week 16 up until week 17, 24/04/2023) there have been 8 laboratory-confirmed measles cases detected across the country, of which the majority were from Limpopo (5).
- The percentage of samples testing positive (PTP) decreased from 20% of 83 samples tested in week 15 to 14% of 53 samples tested in week 16.
- A measles outbreak has been declared in all the provinces in South Africa except for the Eastern Cape. In week 17, no new cases were reported in all provinces.
- The measles strain detected in Limpopo province and North West province is genotype D8 which is similar to the strain in Zimbabwe in the 2022 outbreak.
- In the provinces where an outbreak has been declared, the most affected age groups are still the 5-9-year-olds (43%) with a considerable proportion of cases reported among the 1-4 (24%) and 10-14 age groups (20%).
Outbreak overview
From epidemiological week 40, 2022 (ending 8 October 2022) to week 17, 2023 the NICD has tested 5853 serum samples for measles of which 976 (16.67%) were confirmed measles cases. The number of samples submitted and the percentage of laboratory-confirmed measles-positive cases are shown in Figure 1. From epidemiological week 40 of 2022 to week 17 of 2023, 970 laboratory-confirmed cases were reported from eight provinces with declared measles outbreaks; Limpopo (410 cases), Mpumalanga (108 cases), North West (216 cases), Gauteng (166 cases), Free State (29 cases), Western Cape (14), KwaZulu-Natal (20) and Northern Cape (7) (Table 1). The geographical distribution of cases across South Africa from week 40 of 2022 until week 17 of 2023 is shown in Figure 2The number of blood samples and throat swabs submitted to the NICD for measles serology and PCR testing has decreased from 83 in week 15 compared to 57 in week 16 (Figure 3).
Figure 1. Number of serum samples submitted to the NICD for measles, week 40 2022, until week 16, 2023, and the number (dark green) and % tested positive (red line), by epidemiological week using the date the specimen was collected. *Due to the long weekend, data from week 17 will be updated in next week’s situation report, when complete data from samples collected that week becomes available.
Figure 2. Distribution of laboratory-confirmed measles cases by testing site (red dots – the size of the dot indicates the number of cases from that facility) and district of South Africa (deepening colour of blue indicates the total number of cases by sub-district), from week 40 to week 17, 2023.
Table 1. Cases of laboratory-confirmed measles tested by the NICD from all provinces in South Africa from epidemiological week 40, 2022 to week 17, 2023. Outbreak-associated cases are contained within the red bordered cells* (FS=Free State; GP=Gauteng; KZN=KwaZulu-Natal; LP=Limpopo; MP=Mpumalanga NW=North West; NC=Northern Cape, WC = Western Cape). * A measles outbreak is classified as three or more confirmed laboratory measles cases reported within 30 days of onset of disease, in a district. *Data from week 17 represents partial data, and will be updated in next week’s situation report, when complete data from samples collected that week becomes available.
