title: Temporal association in hospitalizations for tuberculosis, invasive pneumococcal disease and influenza virus illness in South African children.
abstract: BACKGROUND
  The seasonal variability in hospitalization for tuberculosis may in part relate to super-imposed bacterial or predisposing respiratory viral infections. We aimed to study the temporal association between hospitalization for culture-confirmed pulmonary tuberculosis (PTB), invasive pneumococcal disease (IPD) and influenza virus epidemics in South African children.
  
  
  METHODS
  We undertook a retrospective analysis which examined seasonal trends, from 2005 to 2008, for hospitalization for culture-confirmed PTB and IPD among children in relation to the influenza epidemics in Soweto, South Africa. Original time-series of the influenza virus epidemics and hospitalization rates for PTB and IPD were decomposed into three components: a trend cycle component, a seasonal component and an irregular component using the X-11 seasonal adjustment method. To compare the seasonality amongst the three series, the trend and irregular components were removed and only seasonal components examined.
  
  
  RESULTS
  Across the study period, the influenza virus epidemics peaked during May to July (winter) months, which was closely followed by an increase in the incidence of hospitalization for IPD (August to October) and PTB (August to November).
  
  
  CONCLUSIONS
  Within- and between-year temporal changes associated with childhood TB hospitalization may in part be driven by factors which influence temporal changes in pneumococcal disease, including potential variability in the severity of influenza virus epidemics in temperate climates. The dynamics of the interplay between the host and these infectious agents appears to be complex and multifactorial.
authors.affiliation: Medical Research Council, Respiratory and Meningeal Pathogens Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; Department of Paediatrics, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: Ziyaad
authors.initials: Z
authors.lastname: Dangor
authors.affiliation: Medical Research Council, Respiratory and Meningeal Pathogens Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: Alane
authors.initials: A
authors.lastname: Izu
authors.affiliation: Medical Research Council, Respiratory and Meningeal Pathogens Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: David P
authors.initials: DP
authors.lastname: Moore
authors.affiliation: Medical Research Council, Respiratory and Meningeal Pathogens Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: Marta C
authors.initials: MC
authors.lastname: Nunes
authors.affiliation: Medical Research Council, Respiratory and Meningeal Pathogens Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: Fatima
authors.initials: F
authors.lastname: Solomon
authors.affiliation: Mycobacteriology Referral Laboratory, National Health Laboratory Service, Johannesburg, South Africa.
authors.forename: Natalie
authors.initials: N
authors.lastname: Beylis
authors.affiliation: Center for Respiratory and Meningitis Diseases, National Institute for Communicable Diseases: A Division of National Health Laboratory Service, Sandringham, South Africa.
authors.forename: Anne
authors.initials: A
authors.lastname: von Gottberg
authors.affiliation: Center for Respiratory and Meningitis Diseases, National Institute for Communicable Diseases: A Division of National Health Laboratory Service, Sandringham, South Africa.
authors.forename: Johanna M
authors.initials: JM
authors.lastname: McAnerney
authors.affiliation: Medical Research Council, Respiratory and Meningeal Pathogens Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Johannesburg, South Africa; Center for Respiratory and Meningitis Diseases, National Institute for Communicable Diseases: A Division of National Health Laboratory Service, Sandringham, South Africa.
authors.forename: Shabir A
authors.initials: SA
authors.lastname: Madhi
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D060085:Coinfection; D005260:Female; D015658:HIV Infections / Q000453:epidemiology; D006760:Hospitalization; D006801:Humans; D007223:Infant; D007251:Influenza, Human / Q000453:epidemiology*; D008297:Male; D011008:Pneumococcal Infections / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors; D012621:Seasons; D013019:South Africa / Q000453:epidemiology; D062211:Spatio-Temporal Analysis; D014376:Tuberculosis / Q000453:epidemiology*