Defining the South African Acute Respiratory Infectious Disease Season

Ogone Motlogeloa; Jennifer M Fitchett; Neville Sweijd

doi:10.3390/ijerph20021074

Defining the South African Acute Respiratory Infectious Disease Season

Int J Environ Res Public Health. 2023 Jan 7;20(2):1074. doi: 10.3390/ijerph20021074.

Authors

Ogone Motlogeloa¹, Jennifer M Fitchett¹, Neville Sweijd²

Affiliations

¹ School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, Johannesburg 2050, South Africa.
² Alliance for Collaboration on Climate and Earth Systems Science (ACCESS), Council for Scientific and Industrial Research (CSIR), Pretoria 0001, South Africa.

Abstract

The acute respiratory infectious disease season, or colloquially the "flu season", is defined as the annually recurring period characterized by the prevalence of an outbreak of acute respiratory infectious diseases. It has been widely agreed that this season spans the winter period globally, but the precise timing or intensity of the season onset in South Africa is not well defined. This limits the efficacy of the public health sector to vaccinate for influenza timeously and for health facilities to synchronize efficiently for an increase in cases. This study explores the statistical intensity thresholds in defining this season to determine the start and finish date of the acute respiratory infectious disease season in South Africa. Two sets of data were utilized: public-sector hospitalization data that included laboratory-tested RSV and influenza cases and private-sector medical insurance claims under ICD 10 codes J111, J118, J110, and J00. Using the intensity threshold methodology proposed by the US CDC in 2017, various thresholds were tested for alignment with the nineteen-week flu season as proposed by the South African NICD. This resulted in varying thresholds for each province. The respiratory disease season commences in May and ends in September. These findings were seen in hospitalization cases and medical insurance claim cases, particularly with influenza-positive cases in Baragwanath hospital for the year 2019. These statistically determined intensity thresholds and timing of the acute respiratory infectious disease season allow for improved surveillance and preparedness among the public and private healthcare.

Keywords: RSV; common cold; influenza; public health; seasonality; winter.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Communicable Diseases*
Hospitalization
Humans
Influenza, Human* / epidemiology
Respiratory Syncytial Virus Infections* / epidemiology
Seasons
South Africa / epidemiology

Grants and funding

O.M. has received funding for her doctoral studies from the South African Weather Service, the South African National Research Foundation (136477), and the University of the Witwatersrand Postgraduate Merit Award. J.F. received funding from the National Research Foundation and the University of the Witwatersrand Research Committee Friedel Sellschop Award. O.M., J.M. and N.S. received funding from the National Research Fund ESSRP Grant, and South Africa/Japan Joint Collaboration.