title: Facemasks and hand hygiene to prevent influenza transmission in households: a cluster randomized trial.
abstract: BACKGROUND
  Few data are available about the effectiveness of nonpharmaceutical interventions for preventing influenza virus transmission.
  
  
  OBJECTIVE
  To investigate whether hand hygiene and use of facemasks prevents household transmission of influenza.
  
  
  METHODS
  Cluster randomized, controlled trial. Randomization was computer generated; allocation was concealed from treating physicians and clinics and implemented by study nurses at the time of the initial household visit. Participants and personnel administering the interventions were not blinded to group assignment. (ClinicalTrials.gov registration number: NCT00425893)
  
  
  METHODS
  Households in Hong Kong.
  
  
  METHODS
  407 people presenting to outpatient clinics with influenza-like illness who were positive for influenza A or B virus by rapid testing (index patients) and 794 household members (contacts) in 259 households.
  
  
  METHODS
  Lifestyle education (control) (134 households), hand hygiene (136 households), or surgical facemasks plus hand hygiene (137 households) for all household members.
  
  
  METHODS
  Influenza virus infection in contacts, as confirmed by reverse-transcription polymerase chain reaction (RT-PCR) or diagnosed clinically after 7 days.
  
  
  RESULTS
  Sixty (8%) contacts in the 259 households had RT-PCR-confirmed influenza virus infection in the 7 days after intervention. Hand hygiene with or without facemasks seemed to reduce influenza transmission, but the differences compared with the control group were not significant. In 154 households in which interventions were implemented within 36 hours of symptom onset in the index patient, transmission of RT-PCR-confirmed infection seemed reduced, an effect attributable to fewer infections among participants using facemasks plus hand hygiene (adjusted odds ratio, 0.33 [95% CI, 0.13 to 0.87]). Adherence to interventions varied.
  
  
  CONCLUSIONS
  The delay from index patient symptom onset to intervention and variable adherence may have mitigated intervention effectiveness.
  
  
  CONCLUSIONS
  Hand hygiene and facemasks seemed to prevent household transmission of influenza virus when implemented within 36 hours of index patient symptom onset. These findings suggest that nonpharmaceutical interventions are important for mitigation of pandemic and interpandemic influenza.
  
  
  BACKGROUND
  Centers for Disease Control and Prevention.
authors: School of Public Health and University of Hong Kong, Cyberport 3, Pokfulam, Hong Kong SAR. bcowling@hku.hk
authors: Benjamin J
authors: BJ
authors: Cowling
authors: Kwok-Hung
authors: KH
authors: Chan
authors: Vicky J
authors: VJ
authors: Fang
authors: Calvin K Y
authors: CK
authors: Cheng
authors: Rita O P
authors: RO
authors: Fung
authors: Winnie
authors: W
authors: Wai
authors: Joey
authors: J
authors: Sin
authors: Wing Hong
authors: WH
authors: Seto
authors: Raymond
authors: R
authors: Yung
authors: Daniel W S
authors: DW
authors: Chu
authors: Billy C F
authors: BC
authors: Chiu
authors: Paco W Y
authors: PW
authors: Lee
authors: Ming Chi
authors: MC
authors: Chiu
authors: Hoi Che
authors: HC
authors: Lee
authors: Timothy M
authors: TM
authors: Uyeki
authors: Peter M
authors: PM
authors: Houck
authors: J S Malik
authors: JS
authors: Peiris
authors: Gabriel M
authors: GM
authors: Leung
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005191:Family Characteristics; D006235:Hand Disinfection; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D009980:Influenza A virus / Q000302:isolation & purification; D009981:Influenza B virus / Q000302:isolation & purification; D007251:Influenza, Human / Q000175:diagnosis / Q000517:prevention & control* / Q000635:transmission; D008297:Male; D008397:Masks; D008875:Middle Aged; D010349:Patient Compliance; D010353:Patient Education as Topic; D011446:Prospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012307:Risk Factors; D013997:Time Factors; D055815:Young Adult