Issued by the National Institute for Communicable Diseases based on laboratory testing data
Highlights
- The NICD has tested 6193 serum samples for measles since epidemiological week 40, 2022, of which 1034 (17%) were confirmed positive, all from outbreak-affected provinces. In the past week (week 20 up until week 21, 18/05/2023) there have been 19 laboratory-confirmed measles cases detected across the country, of which the majority were from Limpopo (14).
- The percentage of samples testing positive (PTP) decreased from 21% of 76 samples tested in week 19 to 20% of 56 samples tested in week 20.
- Following the national vaccination campaign, there has been a notable decrease in the number of measles cases reported in all provinces affected by the outbreak.
- In week 20, Limpopo province reported a total of 9 new measles cases, while sporadic cases were also reported in Gauteng (1), Mpumalanga (1) and Western Cape (1) provinces. No new cases were reported in Northern Cape and KwaZulu-Natal provinces in the past 6 weeks.
- 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.
Outbreak overview
From epidemiological week 40, 2022 (ending 8 October 2022) to week 21, 2023 the NICD has tested 6193 serum samples for measles of which 1040 (17%) 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 21 of 2023, 1034 laboratory-confirmed cases were reported from eight provinces with declared measles outbreaks; Limpopo (459 cases), Mpumalanga (109 cases), North West (217 cases), Gauteng (175 cases), Free State (32 cases), Western Cape (15), KwaZulu-Natal (20) and Northern Cape (7) (Table 1). The geographical distribution of cases across South Africa from week 40 of 2022 until week 21 of 2023 is shown in Figure 2The number of blood samples and throat swabs submitted to the NICD for measles serology and PCR testing decreased from 76 in week 19 to 56 in week 20.
Figure 1. Number of serum samples submitted to the NICD for measles, week 40 2022, until week 21, 2023, and the number (dark green) and % tested positive (red line), by epidemiological week using the date the specimen was collected. *Data from week 21 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 21, 2023.
