Efficacy of face masks and respirators in preventing upper respiratory tract bacterial colonization and co-infection in hospital healthcare workers

AbstractObjectiveWe compared the efficacy of medical masks (MM) and N95 respirators (N95) in preventing bacterial colonization/infection in healthcare workers (HCWs).MethodsA cluster randomized clinical trial (RCT) of 1441 hospital HCWs randomized to medical masks or N95 respirators, and compared to 481 control HCWs, was performed in Beijing, China, during the winter season of 2008–2009. Participants were followed for development of clinical respiratory illness (CRI). Symptomatic subjects were tested for Streptococcus pneumoniae, Bordetella pertussis, Chlamydia pneumoniae, Mycoplasma pneumoniae or Haemophilus influenza type B by multiplex polymerase chain reaction (PCR).ResultsThe rate of bacterial colonization was 2.8% in the N95 group (p=0.02), 5.3% among medical mask users (p