South African Measles Outbreak Update 2023 ( 16 FEBRUARY )

Highlights

• The NICD has tested 3694 serum samples for measles since epidemiological week 40, 2022, of which 560 (15.1%) were confirmed positive. In outbreak-affected provinces, 537 cases have been reported since week 40, 2022. In the past weeks (week 05 up until mid-week 06, 2023), 76 laboratory-confirmed measles cases were detected across the country, of which 73 are from outbreak-affected provinces.
• In week 05, the percentage of samples testing positive (PTP) increased to 20% of the 251 samples tested, compared with a lower PTP (13%) in week 04, 2023. The PTP for week 06 has further increased to 25%.
• In week 06 Gauteng reported 12 new cases, the largest number of new cases of all the outbreak provinces.
• In provinces where an outbreak has been declared, the most affected age groups are still the 5–9-year-olds (41%) with a considerable proportion of cases reported among the 1-4 (26%) and 10-14 age groups (18%). Vaccination campaigns should therefore also include children aged 10 to 14
• The majority of cases (72%) were reported from primary healthcare facilities, and the highest proportion of cases reported from hospitals (53%) 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 mid-week 06, 2023 (ending 11 February 2023) the NICD has tested 3694 serum samples for measles of which 560 (15.1%) 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 06 of 2023, 537 laboratory-confirmed cases were reported from five provinces with declared measles outbreaks; Limpopo (190 cases), Mpumalanga (94 cases), North West (169 cases), Gauteng (61 cases), and Free State (23 cases) (Table 1). The geographical distribution of cases across South Africa from week 40 of 2022 until week 06 of 2023 is shown in Figure 2he number of measles cases continues to increase in blood samples and throat swabs submitted to the NICD for measles serology and PCR testing.

Figure 1. The number of serum samples submitted to the NICD for measles, week 40 2022, until week 06, 2023 and the number (dark green) and % tested positive (red line), by epidemiological week using the date the specimen was collected. *Data from week 06 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 (deepening the colour of blue indicates the total number of cases by sub-district), from week 40 to week 06, 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 06, 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 06 represent partial data and will be updated in next week’s situation report when complete data from samples collected that week becomes available.