Post by Nadica (She/Her) on Nov 5, 2024 6:10:50 GMT
The burden of SARS-CoV-2 Infection and Severe Illness in South Africa March 2020-August 2022: A synthesis of epidemiological data - Preprint posted Nov 4, 2024
Abstract
Introduction Data on burden of SARS-CoV-2 infections by age group and for different severity levels are lacking. We estimated the South African SARS-CoV-2 disease burden and severity, describing changes in the shape of the disease burden pyramid with successive waves. Methods We estimated SARS-CoV-2 medically and non-medically attended illness stratified by severity (mild, severe non-fatal, and fatal) during the initial five waves, spanning 1 March 2020 through 13 August 2022. We utilised individual-level national surveillance, healthcare-utilisation and serosurvey data to calculate wave-specific hospitalisation-fatality (HFR) and infection-fatality ratios (IFR). We estimated wave-specific incidence rates per 100,000 population with 95% confidence intervals derived from bootstrapping the individual-level data. Results On 13 August 2022, the estimated cumulative number of SARS-CoV-2 infections in South Africa was 105 million, of which 399,886 (0.38%) were severe non-fatal and 258,754 (0.25%) fatal. 29% of severe non-fatal illness and 55% of deaths occurred outside hospital. The highest burden of severe and fatal illness was during the Delta wave (wave 3), and the HFR across the initial three waves was similar (range 31%-34%). Although there were more infections during the Omicron BA.1 wave (wave 4), there was a substantial reduction in HFR (14%). Successive waves saw a reduction in the rate of increase in mortality and hospitalisations with increasing age. Conclusions The substantial South African national burden of SARS-CoV-2 for the initial five waves contradicts the belief of minimal impact in Africa. A high proportion of severe non-fatal and fatal illness occurred outside of hospital, highlighting the importance of studies of health-seeking and vital registration systems to document the full burden of illness. Highest burden of severe illness and death was in the Delta wave. Following Omicron emergence severe illness reduced, and age-distribution for the incidence of medically attended severe non-fatal illness shifted to a J-shape, possibly reflecting the shift from widespread transmission to an endemic pattern.
Abstract
Introduction Data on burden of SARS-CoV-2 infections by age group and for different severity levels are lacking. We estimated the South African SARS-CoV-2 disease burden and severity, describing changes in the shape of the disease burden pyramid with successive waves. Methods We estimated SARS-CoV-2 medically and non-medically attended illness stratified by severity (mild, severe non-fatal, and fatal) during the initial five waves, spanning 1 March 2020 through 13 August 2022. We utilised individual-level national surveillance, healthcare-utilisation and serosurvey data to calculate wave-specific hospitalisation-fatality (HFR) and infection-fatality ratios (IFR). We estimated wave-specific incidence rates per 100,000 population with 95% confidence intervals derived from bootstrapping the individual-level data. Results On 13 August 2022, the estimated cumulative number of SARS-CoV-2 infections in South Africa was 105 million, of which 399,886 (0.38%) were severe non-fatal and 258,754 (0.25%) fatal. 29% of severe non-fatal illness and 55% of deaths occurred outside hospital. The highest burden of severe and fatal illness was during the Delta wave (wave 3), and the HFR across the initial three waves was similar (range 31%-34%). Although there were more infections during the Omicron BA.1 wave (wave 4), there was a substantial reduction in HFR (14%). Successive waves saw a reduction in the rate of increase in mortality and hospitalisations with increasing age. Conclusions The substantial South African national burden of SARS-CoV-2 for the initial five waves contradicts the belief of minimal impact in Africa. A high proportion of severe non-fatal and fatal illness occurred outside of hospital, highlighting the importance of studies of health-seeking and vital registration systems to document the full burden of illness. Highest burden of severe illness and death was in the Delta wave. Following Omicron emergence severe illness reduced, and age-distribution for the incidence of medically attended severe non-fatal illness shifted to a J-shape, possibly reflecting the shift from widespread transmission to an endemic pattern.