TY - JOUR
T1 - A cluster randomized clinical trial comparing fit-tested and non-fit-tested N95 respirators to medical masks to prevent respiratory virus infection in health care workers
AU - MacIntyre, Chandini Raina
AU - Wang, Quanyi
AU - Cauchemez, Simon
AU - Seale, Holly
AU - Dwyer, Dominic E.
AU - Yang, Peng
AU - Shi, Weixian
AU - Gao, Zhanhai
AU - Pang, Xinghuo
AU - Zhang, Yi
AU - Wang, Xiaoli
AU - Duan, Wei
AU - Rahman, Bayzidur
AU - Ferguson, Neil
PY - 2011/5
Y1 - 2011/5
N2 - Background We compared the efficacy of medical masks, N95 respirators (fit tested and non fit tested), in health care workers (HCWs). Methods A cluster randomized clinical trial (RCT) of 1441 HCWs in 15 Beijing hospitals was performed during the 2008/2009 winter. Participants wore masks or respirators during the entire work shift for 4weeks. Outcomes included clinical respiratory illness (CRI), influenza-like illness (ILI), laboratory-confirmed respiratory virus infection and influenza. A convenience no-mask/respirator group of 481 health workers from nine hospitals was compared. Findings The rates of CRI (3·9% versus 6·7%), ILI (0·3% versus 0·6%), laboratory-confirmed respiratory virus (1·4% versus 2·6%) and influenza (0·3% versus 1%) infection were consistently lower for the N95 group compared to medical masks. By intention-to-treat analysis, when P values were adjusted for clustering, non-fit-tested N95 respirators were significantly more protective than medical masks against CRI, but no other outcomes were significant. The rates of all outcomes were higher in the convenience no-mask group compared to the intervention arms. There was no significant difference in outcomes between the N95 arms with and without fit testing. Rates of fit test failure were low. In a post hoc analysis adjusted for potential confounders, N95 masks and hospital level were significant, but medical masks, vaccination, handwashing and high-risk procedures were not. Interpretation Rates of infection in the medical mask group were double that in the N95 group. A benefit of respirators is suggested but would need to be confirmed by a larger trial, as this study may have been underpowered. The finding on fit testing is specific to the type of respirator used in the study and cannot be generalized to other respirators. Trial registration Australian New Zealand Clinical Trials Registry (ANZCTR), ACTRN: ACTRN12609000257268 (http://www.anzctr.org.au).
AB - Background We compared the efficacy of medical masks, N95 respirators (fit tested and non fit tested), in health care workers (HCWs). Methods A cluster randomized clinical trial (RCT) of 1441 HCWs in 15 Beijing hospitals was performed during the 2008/2009 winter. Participants wore masks or respirators during the entire work shift for 4weeks. Outcomes included clinical respiratory illness (CRI), influenza-like illness (ILI), laboratory-confirmed respiratory virus infection and influenza. A convenience no-mask/respirator group of 481 health workers from nine hospitals was compared. Findings The rates of CRI (3·9% versus 6·7%), ILI (0·3% versus 0·6%), laboratory-confirmed respiratory virus (1·4% versus 2·6%) and influenza (0·3% versus 1%) infection were consistently lower for the N95 group compared to medical masks. By intention-to-treat analysis, when P values were adjusted for clustering, non-fit-tested N95 respirators were significantly more protective than medical masks against CRI, but no other outcomes were significant. The rates of all outcomes were higher in the convenience no-mask group compared to the intervention arms. There was no significant difference in outcomes between the N95 arms with and without fit testing. Rates of fit test failure were low. In a post hoc analysis adjusted for potential confounders, N95 masks and hospital level were significant, but medical masks, vaccination, handwashing and high-risk procedures were not. Interpretation Rates of infection in the medical mask group were double that in the N95 group. A benefit of respirators is suggested but would need to be confirmed by a larger trial, as this study may have been underpowered. The finding on fit testing is specific to the type of respirator used in the study and cannot be generalized to other respirators. Trial registration Australian New Zealand Clinical Trials Registry (ANZCTR), ACTRN: ACTRN12609000257268 (http://www.anzctr.org.au).
KW - Health workers
KW - Influenza
KW - Masks
KW - PPE
UR - http://www.scopus.com/inward/record.url?scp=79953803806&partnerID=8YFLogxK
U2 - 10.1111/j.1750-2659.2011.00198.x
DO - 10.1111/j.1750-2659.2011.00198.x
M3 - Article
C2 - 21477136
AN - SCOPUS:79953803806
SN - 1750-2640
VL - 5
SP - 170
EP - 179
JO - Influenza and Other Respiratory Viruses
JF - Influenza and Other Respiratory Viruses
IS - 3
ER -