Table 2.

Summary of Included Studies

CharacteristicsOutcomes
EfficacyaEffectivenessb
PublicationStudy TypePopulationPathogen/ParticleFiltrationFitAirflowInfection
MacIntyre et al17Randomized trialHealth care clinicians in high-risk wards in Vietnam (N = 1,607)Viral respiratory infection,c aerosolized particlesCloth < medicalCloth < medical († infection in cloth)
Davies et al9Nonrandomized trialVolunteers, general population (N = 21)Aerosolized virus,d aerosolized bacteriadCloth < medicalCloth < medicalCloth < medical
Liu et al10Nonrandomized trialSurgeons (N = 50)BacteriadCloth < medicalCloth < medical
Sellers et al16Nonrandomized trialHuman subjects exposed to hand-and-foot virus (N =8)PicornaviruseCloth = medical († infection in both)
van der Sande et al12Nonrandomized trialVolunteers, general population (N = 39)Particles (0.02-1 μm)Cloth < medical
Furuhashi13Laboratory efficacy studyBacteriadCloth < medicalCloth < medical
Ma et al14Laboratory efficacy studyAerosolized virusfCloth = medical
Rengasamy et al11Laboratory efficacy studyAerosolized particles (20-1,000 nm)Cloth < N95
Quesnel15Single-case experimentSingle human test subject, general populationBacteriadCloth = medical
  • hMPV = human metapneumovirus; PCR = polymerase chain reaction.

  • Note: < indicates less effective or efficacious; = indicates no difference in effectiveness or efficacy; † indicates increased incidence.

  • a Efficacy refers to the performance of mask materials in a laboratory setting.

  • b Effectiveness refers to the performance of masks when used by human subjects in clinical environments.

  • c Influenza-like illness and/or pharyngeal swab multiplex PCR-confirmed infection (rhinovirus, hMPV, influenza, etc).

  • d Viable pathogen detected via postfiltration colony formation.

  • e Viral colony formation from nasal swab.

  • f Virus detected via postfiltration PCR.