Plastic face shields not effective without masks, say experts

Zhaki Abdullah

SINGAPORE (CNA) – While plastic face shields can be used in place of masks while out and about in Singapore, experts advise that surgical or reusable masks should be worn as well for effective protection.

The issue has stirred debate online. In a post in the Facebook group, Singapore Foodie Group, that has since been removed, one person asked if wearing a face shield alone is sufficient.

The answer, according to the Singaporean Ministry of Health, is yes. On its website, it states any mask – including plastic face shields – can be worn as this offers “adequate basic protection” for people who need to leave their homes during the “circuit breaker” period.

But infectious disease experts caution that such face shields provide limited protection and should be worn together with other masks in order to be effective.

“It is important to note that the use of plastic face shields is primarily aimed at minimising droplet exposure to the eyes and other parts of the face not covered by the face mask – protecting oneself from others – and to minimise projections of droplets too, protecting others from oneself,” said Professor Teo Yik Ying, Dean of the National University of Singapore’s Saw Swee Hock School of Public Health.

“Such droplets may be projected when someone coughs or sneezes, or even in the normal course of conversations.”

Dr Leong Hoe Nam, an infectious disease specialist from the Mount Elizabeth Novena Hospital, said such face shields would not be useful for most members of the public.

“It does not replace the surgical masks or the reusable cloth masks,” he said.

Dr Leong noted that in the healthcare line, such face shields are often used in place of goggles, which can be uncomfortable if worn for a long period.

The open nature of the face shield protects users against “more forceful projections” but does not completely eliminate exposure or dissipation of droplets, Professor Teo noted.

“As such, the proper use of plastic face shields should still be accompanied by an appropriate face mask,” he added.

For healthcare workers, this refers to either surgical or N95 face masks, given that they work in a high-risk setting with the possibility of exposure to aerosolised particles and droplets, he said.

Meanwhile, for members of the public, who are in a “generally lower-risk setting”, reusable cloth masks can be used instead, said Professor Teo.

Though the use of face masks was previously encouraged only for those who are sick, the use of such masks while outside was made mandatory in Singapore on April 14 as part of efforts to stem the spread of COVID-19.

Those who refuse to wear a mask face are fined SGD300 for a first offence, and a SGD1,000 fine for a second offence.

On April 17, three days after the measure was introduced, about 100 people were fined for not wearing masks while in public.