Determining the Provincial and National Burden of Influenza-Associated Severe Acute Respiratory Illness in South Africa Using a Rapid Assessment Methodology

Jillian Murray; Adam Cohen; Sibongile Walaza; Michelle Groome; Shabir Madhi; Ebrahim Variava; Kathleen Kahn; Halima Dawood; Stefano Tempia; Akhona Tshangela; Marietje Venter; Daniel Feikin; Cheryl Cohen

doi:10.1371/journal.pone.0132078

Determining the Provincial and National Burden of Influenza-Associated Severe Acute Respiratory Illness in South Africa Using a Rapid Assessment Methodology

PLoS One. 2015 Jul 8;10(7):e0132078. doi: 10.1371/journal.pone.0132078. eCollection 2015.

Authors

Affiliations

¹ Johns Hopkins International Vaccine Access Center, Baltimore, Maryland, United States of America.
² Centers for Disease Control and Prevention, Pretoria, South Africa; Centers for Disease Control and Prevention, Atlanta, United States of America.
³ National Institute of Communicable Diseases, Johannesburg, South Africa.
⁴ Medical Research Council: Respiratory and, Meningeal Pathogens Research Unit, Johannesburg, South Africa.
⁵ National Institute of Communicable Diseases, Johannesburg, South Africa; Medical Research Council: Respiratory and, Meningeal Pathogens Research Unit, Johannesburg, South Africa; Schools of Public Health and Pathology, University of the Witwatersrand, Johannesburg, South Africa.
⁶ Klerksdorp Tshepong Hospital, Klerksdorp, South Africa.
⁷ Schools of Public Health and Pathology, University of the Witwatersrand, Johannesburg, South Africa; University of KwaZulu-Natal, Durban, South Africa; Umeå University, Umeå, Sweden; INDEPTH Network, Accra, Ghana.
⁸ University of KwaZulu-Natal, Durban, South Africa; Pietermaritzburg Metropolitan Hospital Complex, Pietermaritzburg, South Africa.
⁹ Centers for Disease Control and Prevention, Pretoria, South Africa; National Institute of Communicable Diseases, Johannesburg, South Africa.
¹⁰ Centers for Disease Control and Prevention, Atlanta, United States of America; National Institute of Communicable Diseases, Johannesburg, South Africa; Zoonoses Research Unit, Department of Medical Virology, University of Pretoria, Pretoria, South Africa.
¹¹ Johns Hopkins International Vaccine Access Center, Baltimore, Maryland, United States of America; Centers for Disease Control and Prevention, Atlanta, United States of America.
¹² National Institute of Communicable Diseases, Johannesburg, South Africa; Schools of Public Health and Pathology, University of the Witwatersrand, Johannesburg, South Africa.

Abstract

Local disease burden data are necessary to set national influenza vaccination policy. In 2010 the population of South Africa was 50 million and the HIV prevalence was 11%. We used a previously developed methodology to determine severe influenza burden in South Africa. Hospitalized severe acute respiratory illness (SARI) incidence was calculated, stratified by HIV status, for four age groups using data from population-based surveillance in one site situated in Gauteng Province for 2009-2011. These rates were adjusted for each of the remaining 8 provinces based on their prevalence of risk factors for pneumonia and healthcare-seeking behavior. We estimated non-hospitalized influenza-associated SARI from healthcare utilization surveys at two sites and used the percent of SARI cases positive for influenza from sentinel surveillance to derive the influenza-associated SARI rate. We applied rates of hospitalized and non-hospitalized influenza-associated SARI to census data to calculate the national number of cases. The percent of SARI cases that tested positive for influenza ranged from 7-17% depending on age group, year, province and HIV status. In 2010, there were an estimated 21,555 total severe influenza cases in HIV-uninfected individuals and 13,876 in HIV-infected individuals. In 2011, there were an estimated 29,892 total severe influenza cases in HIV-uninfected individuals and 17,289 in HIV-infected individuals. The incidence of influenza-associated SARI was highest in children <5 years and was higher in HIV-infected than HIV-uninfected persons in all age groups. Influenza virus was associated with a substantial amount of severe disease, especially in young children and HIV-infected populations in South Africa.

Publication types

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

MeSH terms

Cost of Illness*
HIV Seropositivity / complications
Hospitalization / statistics & numerical data
Humans
Incidence
Influenza, Human / complications*
Influenza, Human / epidemiology*
Models, Biological
Sentinel Surveillance*
Severe Acute Respiratory Syndrome / complications*
Severe Acute Respiratory Syndrome / epidemiology*
South Africa

Grants and funding

This work was supported by the Global Health Research Graduate Student Award, Centre for Global Health, Johns Hopkins Bloomberg School of Public Health: http://www.hopkinsglobalhealth.org/. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.