Mortality amongst patients with influenza-associated severe acute respiratory illness, South Africa, 2009-2013

• Published in: PloS one Vol. 10; no. 3; p. e0118884
• Main Authors: Cohen, Cheryl, Moyes, Jocelyn, Tempia, Stefano, Groome, Michelle, Walaza, Sibongile, Pretorius, Marthi, Dawood, Halima, Chhagan, Meera, Haffejee, Summaya, Variava, Ebrahim, Kahn, Kathleen, von Gottberg, Anne, Wolter, Nicole, Cohen, Adam L, Malope-Kgokong, Babatyi, Venter, Marietjie, Madhi, Shabir A
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 18.03.2015; Public Library of Science (PLoS)
• Subjects: Acute Disease - epidemiology; Acute Disease - mortality; Adolescent; Adult; Adults; Age; Aged; Analysis; Antiretroviral agents; Catchments; Child; Child, Preschool; Children; Confidence intervals; Deoxyribonucleic acid; DNA; Fatalities; Female; HIV; Hospitals; Human immunodeficiency virus; Humans; Incidence; Infant; Infants; Infections; Influenza; Influenza vaccines; Influenza, Human - complications; Influenza, Human - epidemiology; Influenza, Human - mortality; Male; Middle Aged; Mortality; Patient outcomes; Patients; Polymerase chain reaction; Respiratory diseases; Respiratory Tract Infections - complications; Respiratory Tract Infections - epidemiology; Respiratory Tract Infections - mortality; Respiratory Tract Infections - virology; Risk Factors; Risk groups; Seasons; Sentinel Surveillance; South Africa - epidemiology; Studies; Swine flu; Vaccination; Viruses; Young Adult; South Africa; Atlanta Georgia; Mexico; Georgia; United States > US
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0118884

Data on the burden and risk groups for influenza-associated mortality from Africa are limited. We aimed to estimate the incidence and risk-factors for in-hospital influenza-associated severe acute respiratory illness (SARI) deaths. Hospitalised patients with SARI were enrolled prospectively in four provinces of South Africa from 2009-2013. Using polymerase chain reaction, respiratory samples were tested for ten respiratory viruses and blood for pneumococcal DNA. The incidence of influenza-associated SARI deaths was estimated at one urban hospital with a defined catchment population. We enrolled 1376 patients with influenza-associated SARI and 3% (41 of 1358 with available outcome data) died. In patients with available HIV-status, the case-fatality proportion (CFP) was higher in HIV-infected (5%, 22/419) than HIV-uninfected individuals (2%, 13/620; p = 0.006). CFPs varied by age group, and generally increased with increasing age amongst individuals >5 years (p<0.001). On multivariable analysis, factors associated with death were age-group 45-64 years (odds ratio (OR) 4.0, 95% confidence interval (CI) 1.01-16.3) and ≥65 years (OR 6.5, 95%CI 1.2-34.3) compared to 1-4 year age-group who had the lowest CFP, HIV-infection (OR 2.9, 95%CI 1.1-7.8), underlying medical conditions other than HIV (OR 2.9, 95%CI 1.2-7.3) and pneumococcal co-infection (OR 4.1, 95%CI 1.5-11.2). The estimated incidence of influenza-associated SARI deaths per 100,000 population was highest in children <1 year (20.1, 95%CI 12.1-31.3) and adults aged 45-64 years (10.4, 95%CI 8.4-12.9). Adjusting for age, the rate of death was 20-fold (95%CI 15.0-27.8) higher in HIV-infected individuals than HIV-uninfected individuals. Influenza causes substantial mortality in urban South Africa, particularly in infants aged <1 year and HIV-infected individuals. More widespread access to antiretroviral treatment and influenza vaccination may reduce this burden.