Wearing Purdah May Not Prevent Covid-19, Masks Still Better: Experts

Doctors also say face shields should not be used as a substitute for face masks.

KUALA LUMPUR, August 13 — Medical experts say that some form of face covering, like veils or headscarves, is better than none, but it may not be adequate to prevent the spread of coronavirus.

Former Health deputy director-general Dr Christopher Lee said that ideally, one ought to follow the World Health Organization’s (WHO) recommendation on wearing three-ply fabric masks that should fit snugly over the face, covering the nose and mouth extending below the chin.

“With three-layered fabric masks as recommended by WHO, the effects on environmental contamination is significantly better,” Dr Lee, who is a consultant infectious diseases specialist, told CodeBlue.

Senior Defence Minister Ismail Sabri Yaakob suggested last Monday to the Ministry of Health (MOH) to conduct research on the efficacy of various types of face coverings, including purdah (veil) or selendang (headscarf), as well as face shields, in preventing coronavirus transmission.

Ismail Sabri brought this up amid public backlash against the punitive enforcement of wearing face masks in crowded public areas, subject to RM1,000 fines for non-compliance, and criticism from lawmakers that low-income people may not be able to afford surgical or fabric face masks.

“A single-layered fabric face mask is better than no mask, but a three-ply fabric mask is better than a single-layered fabric mask,” former Malaysian Medical Association (MMA) president Dr Milton Lum said to CodeBlue, when asked to comment on the use of a single-layer fabric face covering.

“As far as I know, there is no published literature for the use of purdah in the prevention of spread of Covid-19 virus, but the high degree of increasing load of positive cases in Middle East, where the purdah is used frequently, raises its effectiveness,” Dr Lum added, when asked if purdah will suffice instead of using a mask in preventing the spread of coronavirus.

Dr Tan Poh Tin, a consultant paediatrician and public health specialist, wrote in a column on CodeBlue that scarves (selendang) are less effective in preventing coronavirus — which is spread primarily through small droplets expelled from the nose or mouth when a person infected with Covid-19 speaks, coughs, or sneezes — depending on the material and layering.

“Bandannas or purdahs may break up air droplets into finer particles, so may not be good for source control (i.e protecting others).”

Dr Tan also said that the best materials for a do-it-yourself (DIY) face mask include cotton T-shirts, pillowcases, or other cotton material (highest thread count preferred) and hybrid layers (cotton-silk, cotton-chiffon, cotton flannel) that seem to filter better.

Senior consultant paediatrician Dr Amar-Singh HSS told CodeBlue: “Instead of a single-layered face covering like a shawl, bandanna, purdah or head covering, it is better if we go for a face mask, preferably two- or three-layered, [and] at the same time, follow the WHO guidelines on who should wear a fabric mask and who should wear a surgical mask.”

New York Post reported a study conducted by researchers at Duke University that showed bandannas and knitted face coverings did not offer much protection against Covid-19.

The study also showed that the neck fleece, usually worn by runners, may be worse for coronavirus protection as it has a larger transmission, since it disperses larger droplets into several small droplets, therefore increasing the droplet count.

Dr Lum gave his input on the use of face shields instead of masks, saying: “Some feel that a face shield can replace a mask, but we don’t know the answer to that yet.

“Face shield, just like the mask, depends on the type of material, the frequency of cleaning, how to clean it and how often we replace it. All these have to be answered first.”

Dr Lee said face shields helped to protect the wearer from contact through the eyes (through mucous membranes), so these can be used in addition to face masks.

“The main role of fabric mask is to reduce environmental contamination (through droplets) by the wearer; its role of protecting the wearer is less effective. Face shields alone can’t do that,” he said, when asked on the usage of face shields alone without face masks.

Dr Amar said: “If we are looking for cheaper options to substitute the surgical three-ply mask, a reusable fabric mask is a better option than a face shield.”

Dr Tan cited a study by the United States’ Centres for Disease Control and Prevention (CDC) that stated: “A face shield is primarily used for eye protection for the wearer. At this time, it is not known what level of protection a face shield provides to people nearby from the spray of respiratory droplets from the wearer. There is currently not enough evidence to support the effectiveness of face shields for source control.”

“Face shields can offer an added layer of protection, but should be used in addition to a mask, social distancing, and handwashing, not as a substitute,” she added.

Dr Tan also wrote on CodeBlue about an outbreak that was reported by Insider on several Covid-19 cases among staff and guests at a hotel in Switzerland, where health officials later found that only people who wore plastic shields got infected. Those who wore a face mask, or a combination, did not.

“They concluded that face shields did not protect people but masks did.”

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