(Based on laboratory testing data up until 18 March 2023)
Highlights
- The NICD has tested 5163 serum samples for measles since epidemiological week 40, 2022, of which 844 (16%) were confirmed positive. In outbreak-affected provinces, 838 cases have been reported since week 40, 2022. In the past weeks (week 10 up until week 11, 15/03/2023) there have been 75 laboratory-confirmed measles cases detected across the country all of which were from the outbreak-affected provinces.
- The percentage of samples testing positive (PTP) increased slightly from 19% of 319 samples tested in week 09 to 22% of the 253 samples tested in week 10.
- Measles outbreak has been declared in all the provinces in South Africa except for the Eastern Cape. In the previous week 10, no new cases were reported in KwaZulu-Natal, Mpumalanga, Northern Cape and Western Cape 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 (19%). Vaccination campaigns should therefore also include children aged 10 to 14.
- The majority of cases (69%) were reported from primary healthcare facilities, and the highest proportion of cases reported from hospitals (54%) was reported in children under the age of one.
- Members of the public are urged to ensure their children are vaccinated against measles.
Outbreak overview
From epidemiological week 40, 2022 (ending 8 October 2022) to week 11, 2023 (ending 18 March 2023) the NICD has tested 5163 serum samples for measles of which 844 (16%) 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 11 of 2023, 838 laboratory-confirmed cases were reported from eight provinces with declared measles outbreaks; Limpopo (315 cases), Mpumalanga (106 cases), North West (210 cases), Gauteng (142 cases), Free State (30 cases), Western Cape (11), KwaZulu-Natal (17) and Northern Cape (7) (Table 1). The geographical distribution of cases across South Africa from week 40 of 2022 until week 11 of 2023 is shown in Figure 2. The number of blood samples and throat swabs submitted to the NICD for measles serology and PCR testing has decreased compared to previous weeks (Figure 3).
Figure 1. The number of serum samples submitted to the NICD for measles, week 40 2022, until week 11, 2023, and the number (dark green) and % tested positive (red line), by epidemiological week using the date the specimen was collected. *Data from week 11 represent partial data, and 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 the testing site (red dots – the size of the dot indicates the number of cases from that facility) and district of South Africa (the deepening colour of blue indicates the total number of cases by sub-district), from week 40 to week 11, 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 11, 2023. Outbreak-associated cases are contained within the red bordered cells* (EC=Eastern Cape; FS=Free State; GP =Gauteng; KZN=KwaZulu-Natal; LP=Limpopo; MP=Mpumalanga NW=North West; NC=Northern Cape). * A measles outbreak is classified as three or more confirmed laboratory measles cases reported within 30 days of the onset of disease, in a district. *Data from week 11 represent partial data, and will be updated in next week’s situation report, when complete data from samples collected that week becomes available.
