There is no evidence to support the wearing of surgical masks by healthcare workers for close patient encounters and staff meetings, according to new official guidance.
The guidance was issued by Health Service Executive clinical lead on infection control Prof Martin Cormican in response to moves towards routine wearing of face masks by a number of hospitals.
One Dublin hospital last week advised staff they should wear surgical masks for all patient encounters and meetings between staff where social distancing of at two metres cannot be maintained.
The stated aim of the guidance, which has been adopted by other hospitals, is to prevent the spread of Covid-19 from mildly symptomatic or asymptomatic healthcare workers to patients and colleagues. The recommendation is to use three masks a day if working a 12-hour shift and two for shorter shifts.
However, Prof Cormican said the recommendation “is not supported by evidence and is not consistent with national guidance”.
“The basis for the recommendation is problematic in that it may suggest that the risk from mildly symptomatic healthcare workers attending work can be managed by mask use.
“The recommendation is problematic because it can be expected to promote poor practice in relation to use of masks and thereby increase risk for patients and colleagues.”
“If a hospital recommends adoption of a measure that is not supported by evidence or consensus of expert opinion it has a responsibility to ensure that the measure does not expose staff to increased risk.”
According to Prof Cormican, safe mask use means masks are tied appropriately and removed and discarded any time a person takes a toilet break, answers the phone or uncovers their mouth to eat, drink or for any other reason.
“This cannot be accomplished with the number of masks proposed in the recommendation above.”
Sense of security
While acknowledging many staff are fearful for their own health and the wearing of masks provides “a sense of security for many people” Prof Cormican said the recommendation to use three, or two, masks during a shift is “likely to be counterproductive”.
The World Health Organisation, he pointed out, said mask-wearing by asymptomatic people was not recommended as it caused unnecessary cost and "creates a false sense of security".
Meanwhile, the WHO mission to China found asymptomatic transmission of the virus was "relatively rare and does not appear to be a major driver of transmission".
“There is some uncertainty regarding the extent to which infected but asymptomatic people may disperse infectious droplets but in so far as it occurs, it is likely to be very much less than those who are symptomatic.
“Even if the hypothesis that transmission from truly asymptomatic healthcare workers in the healthcare setting is significant is accepted, there is no evidence that the universal use of surgical masks is effective in reducing this beyond what is achieved by standard precautions (hand hygiene, respiratory hygiene and cough etiquette and environmental cleaning) and minimising interpersonal interaction.”