title: Social mixing patterns within a South African township community: implications for respiratory disease transmission and control.
abstract: A prospective survey of social mixing patterns relevant to respiratory disease transmission by large droplets (e.g., influenza) or small droplet nuclei (e.g., tuberculosis) was performed in a South African township in 2010. A total of 571 randomly selected participants recorded the numbers, times, and locations of close contacts (physical/nonphysical) and indoor casual contacts met daily. The median number of physical contacts was 12 (interquartile range (IQR), 7-18), the median number of close contacts was 20 (IQR, 13-29), and the total number of indoor contacts was 30 (IQR, 12-54). Physical and close contacts were most frequent and age-associative in youths aged 5-19 years. Numbers of close contacts were 40% higher than in corresponding populations in industrialized countries (P < 0.001). This may put township communities at higher risk for epidemics of acute respiratory illnesses. Simulations of an acute influenza epidemic predominantly involved adolescents and young adults, indicating that control strategies should be directed toward these age groups. Of all contacts, 86.2% occurred indoors with potential exposure to respiratory droplet nuclei, of which 27.2%, 20.1%, 20.0%, and 8.0% were in transport, own household, crèche/school, and work locations, respectively. Indoor contact time was long in households and short during transport. High numbers of indoor contacts and intergenerational mixing in households and transport may contribute to exceptionally high rates of tuberculosis transmission reported in the community.
authors.affiliation: Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Western Cape, South Africa. spjohnstonerobertson@gmail.com
authors.forename: Simon P
authors.initials: SP
authors.lastname: Johnstone-Robertson
authors.forename: Daniella
authors.initials: D
authors.lastname: Mark
authors.forename: Carl
authors.initials: C
authors.lastname: Morrow
authors.forename: Keren
authors.initials: K
authors.lastname: Middelkoop
authors.forename: Melika
authors.initials: M
authors.lastname: Chiswell
authors.forename: Lisa D H
authors.initials: LD
authors.lastname: Aquino
authors.forename: Linda-Gail
authors.initials: LG
authors.lastname: Bekker
authors.forename: Robin
authors.initials: R
authors.lastname: Wood
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003198:Computer Simulation; D006801:Humans; D007223:Infant; D007251:Influenza, Human / Q000453:epidemiology / Q000517:prevention & control / Q000635:transmission*; D008962:Models, Theoretical; D012111:Residence Characteristics; D012919:Social Behavior; D013019:South Africa; D014376:Tuberculosis / Q000635:transmission; D055815:Young Adult
references.citation: Int J Tuberc Lung Dis. 2010 Apr;14(4):406-12
references.pmid: 20202297
references.citation: Am Rev Tuberc. 1957 Mar;75(3):420-31
references.pmid: 13403171
references.citation: Clin Infect Dis. 2010 Dec 15;51(12):1362-9
references.pmid: 21070141
references.citation: J Infect Dis. 2009 Oct 15;200(8):1207-11
references.pmid: 19764885
references.citation: Emerg Infect Dis. 2007 Oct;13(10):1491-3
references.pmid: 18257992
references.citation: Am J Hyg. 1951 May;53(3):337-54
references.pmid: 14829446
references.citation: Int J Epidemiol. 2009 Jun;38(3):766-72
references.pmid: 19279073
references.citation: Clin Infect Dis. 2006 Apr 1;42(7):1040-7
references.pmid: 16511773
references.citation: Am J Respir Crit Care Med. 2007 Jan 1;175(1):87-93
references.pmid: 16973982
references.citation: Clin Infect Dis. 2008 Aug 1;47(3):349-55
references.pmid: 18558885
references.citation: J Infect Dis. 1982 Jul;146(1):47-51
references.pmid: 6282993
references.citation: S Afr Med J. 2011 Feb;101(2):111-4
references.pmid: 21678737
references.citation: Int J Tuberc Lung Dis. 2010 Jun;14(6):714-9
references.pmid: 20487609
references.citation: Emerg Infect Dis. 2009 Oct;15(10):1578-81
references.pmid: 19861048
references.citation: Am J Prev Med. 2001 Aug;21(2):79-83
references.pmid: 11457626
references.citation: PLoS Med. 2008 Mar 25;5(3):e74
references.pmid: 18366252
references.citation: Clin Infect Dis. 2010 Aug 15;51(4):401-8
references.pmid: 20604716
references.citation: Epidemiol Infect. 2006 Dec;134(6):1158-66
references.pmid: 16707031
references.citation: Am Rev Respir Dis. 1991 Aug;144(2):302-6
references.pmid: 1907115
references.citation: Am Rev Respir Dis. 1967 Mar;95(3):435-42
references.pmid: 6018703
references.citation: Lancet Infect Dis. 2007 Apr;7(4):257-65
references.pmid: 17376383
references.citation: Curr Opin Infect Dis. 2010 Aug;23(4):293-9
references.pmid: 20592530
references.citation: Am J Infect Control. 2002 Dec;30(8):S1-46
references.pmid: 12461507
references.citation: Arch Environ Health. 1968 Jan;16(1):26-35
references.pmid: 5638222
references.citation: JAMA. 2007 Aug 8;298(6):644-54
references.pmid: 17684187
references.citation: Expert Rev Mol Med. 2010 Dec 09;12:e39
references.pmid: 21144091
references.citation: Proc Natl Acad Sci U S A. 2006 Apr 11;103(15):5935-40
references.pmid: 16585506
references.citation: Am J Epidemiol. 2006 Nov 15;164(10):936-44
references.pmid: 16968863
references.citation: S Afr Med J. 2009 Oct;99(10):738-43
references.pmid: 20128273
references.citation: JAMA. 2010 May 26;303(20):2051-7
references.pmid: 20501927
references.citation: J Infect. 2005 Aug;51(2):103-9
references.pmid: 16038759