title: Findings from a household randomized controlled trial of hand washing and face masks to reduce influenza transmission in Bangkok, Thailand.
abstract: BACKGROUND
  Evidence is needed on the effectiveness of non-pharmaceutical interventions (NPIs) to reduce influenza transmission.
  
  
  METHODS
  We studied NPIs in households with a febrile, influenza-positive child. Households were randomized to control, hand washing (HW), or hand washing plus paper surgical face masks (HW + FM) arms. Study nurses conducted home visits within 24 hours of enrollment and on days 3, 7, and 21. Respiratory swabs and serum were collected from all household members and tested for influenza by RT-PCR or serology.
  
  
  RESULTS
  Between April 2008 and August 2009, 991 (16·5%) of 5995 pediatric influenza-like illness patients tested influenza positive. Four hundred and forty-two index children with 1147 household members were enrolled, and 221 (50·0%) were aged <6 years. Three hundred and ninety-seven (89·8%) households reported that the index patient slept in the parents' bedroom. The secondary attack rate was 21·5%, and 56/345 (16·3%; 95% CI 12·4-20·2%) secondary cases were asymptomatic. Hand-washing subjects reported 4·7 washing episodes/day, compared to 4·9 times/day in the HW + FM arm and 3·9 times/day in controls (P = 0·001). The odds ratios (ORs) for secondary influenza infection were not significantly different in the HW arm (OR = 1·20; 95% CI 0·76-1·88; P-0.442), or the HW + FM arm (OR = 1·16; 95% CI .0·74-1·82; P = 0.525).
  
  
  CONCLUSIONS
  Influenza transmission was not reduced by interventions to promote hand washing and face mask use. This may be attributable to transmission that occurred before the intervention, poor facemask compliance, little difference in hand-washing frequency between study groups, and shared sleeping arrangements. A prospective study design and a careful analysis of sociocultural factors could improve future NPI studies.
authors.affiliation: International Emerging Infections Program, Thailand MOPH-US CDC Collaboration, Nonthaburi, Thailand. marksimmerman@hotmail.com
authors.forename: James M
authors.initials: JM
authors.lastname: Simmerman
authors.forename: Piyarat
authors.initials: P
authors.lastname: Suntarattiwong
authors.forename: Jens
authors.initials: J
authors.lastname: Levy
authors.forename: Richard G
authors.initials: RG
authors.lastname: Jarman
authors.forename: Suchada
authors.initials: S
authors.lastname: Kaewchana
authors.forename: Robert V
authors.initials: RV
authors.lastname: Gibbons
authors.forename: Ben J
authors.initials: BJ
authors.lastname: Cowling
authors.forename: Wiwan
authors.initials: W
authors.lastname: Sanasuttipun
authors.forename: Susan A
authors.initials: SA
authors.lastname: Maloney
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Uyeki
authors.forename: Laurie
authors.initials: L
authors.lastname: Kamimoto
authors.forename: Tawee
authors.initials: T
authors.lastname: Chotipitayasunondh
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000914:Antibodies, Viral / Q000097:blood; D002648:Child; D002675:Child, Preschool; D018562:Disease Transmission, Infectious / Q000517:prevention & control*; D004797:Enzyme-Linked Immunosorbent Assay; D005191:Family Characteristics; D005260:Female; D006235:Hand Disinfection / Q000379:methods*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007251:Influenza, Human / Q000517:prevention & control*; D008297:Male; D008397:Masks / Q000706:statistics & numerical data*; D008875:Middle Aged; D009305:Nasopharynx / Q000821:virology; D009975:Orthomyxoviridae / Q000302:isolation & purification; D012367:RNA, Viral / Q000235:genetics / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction; D044967:Serum / Q000821:virology; D013785:Thailand; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D012367:RNA, Viral