Face Masks

Respiratory protection is an important available strategy for health care workers (HCW) and potentially the general community to protect from infectious diseases. 

Respiratory protection is particularly important during the early phase of outbreaks and pandemics, when vaccine and drugs are unlikely to be available against new and emerging pathogens such as H1N1, H7N9 and Middle East respiratory syndrome coronavirus (MERS-CoV). Various types of masks and respirators are used in the healthcare and community settings to protect from respiratory infections, ranging from cloth masks in low income countries to medical masks and respirators in higher income countries.   

Currently there is uncertainty around the efficacy of masks and respirators with only a small number of randomised controlled clinical trials of masks and respirators, in various settings ranging from the community to hospitals, with diverse interventions and outcome measures. There are no published RCTs on cloth masks, yet they are used widely in countries at high risk of pandemics and emerging infectious diseases such as Vietnam and China. In high income countries, the choice between masks and respirators has been highly controversial, with a polarized heath care community and variation in policy and practice globally.  

MacIntyre et al have done the largest body of research on use of respirators, having published 3 RCTs , including two large trials in health workers. In brief, they have conducted the largest body of research on face masks in hospital health workers to date (conducted in Beijing, China), which shows that N95 respirators provide superior protection than surgical masks. In fact, the evidence that surgical masks provide any protection is sparse, and if they do, it is of a small magnitude. These findings have been controversial and opposed by stakeholder groups in the health sector. Yet the evidence is accumulating.

1st study: Comparing N95 fit and non-fit tested, with surgical masks and control:  http://onlinelibrary.wiley.com/doi/10.1111/j.1750-2659.2011.00198.x/abstract

2nd study: Comparing targeted N95 use vs continuous N95 use vs surgical masks:  http://www.atsjournals.org/doi/pdf/10.1164/rccm.201207-1164OC

Detailed summary:  http://www.cidrap.umn.edu/news-perspective/2013/02/study-full-time-n95-use-offers-best-respiratory-protection

3rd study: Bacterial infections:  http://www.sciencedirect.com/science/article/pii/S0091743514000322#

Last updated:    January 2014

Last reviewed:  7 October 2015