Surgical face masks prevent person-to-person cough transmission of cystic fibrosis pathogens when worn for forty minutes, Queensland respiratory specialists have shown.

While paper masks have previously been shown to prevent the spread of Pseudomonas aeruginosa aerosols during short term wear (ten minutes), new findings show they are also effective when worn for clinically-relevant time periods, according to researchers from QIMR Berghofer Medical Research Institute in Queensland.

Wearing surgical masks in communal hospital areas is now recommended in guidelines to prevent the spread of CF respiratory pathogens, but there is still limited evidence on the duration of wear or their dampness affects transmission, they write in the American Journal of Respiratory and Clinical Care Medicine.

They therefore studied the effects of extended wear masks on cough transmission in a 25 people with CF and chronic P. aeruginosa infection at the Princes Charles Hospital, Brisbane. On microbiological analysis. P. aeruginosa was cultured from the sputum of all patients and was also detected in 20 of 25 samples from their uncovered cough tests.

When a surgical mask was worn, P. aeruginosa was cultured from cough aerosols in nine of 20 participants after 10 minutes, 20 minutes and 40 minutes of mask wear time. In comparison, P. aeruginosa was cultured in four of 20 cough aerosol samples when participants were wearing the ‘gold standard’ N95 fitted face mask.

Study participants also commented that the face masks remained comfortable throughout the  40 minutes of wear time.

Lead author Rebecca Stockwell, a research assistant in the QIMR Lung Bacteria Group, says the study findings extended those of the earlier research showing that face masks reduce the cough transmission of CF pathogens.

The new study also shows that masks remain effective in preventive cough aerosol transmission during extended wear, despite concerns that moisture accumulation might reduce their effectiveness.

“The outcomes of our studies demonstrate that surgical masks are effective and tolerable as source control [3] and support the CF Foundation (USA) recommendations for surgical mask wear to reduce the risk of CF pathogen transmission in the hospital setting,” the authors conclude.