SINGAPORE - Mask-wearing rules should not be eased until the impact of such a move on the healthcare system is deemed to be minimal, said infectious diseases specialist David Lye.
This assessment is likely to be dependent on the number of unvaccinated seniors over the age of 60, said Associate Professor Lye, who is the director of the Infectious Disease Research and Training Office at the National Centre for Infectious Diseases (NCID).
"If everyone can bring the remaining 80,000 unvaccinated seniors to get vaccinated, it will be really helpful," he said.
While it is understandable that many are tired of Covid-19, Prof Lye said it is too early to consider relaxing restrictions now, given the ongoing rise in daily new cases.
"With rising cases that need oxygen or intensive care, and deaths, this is not the time to relax safe management measures. Eventually, when we are certain that the impact on our healthcare system is minimal from Covid-19, our government may relax mask-wearing outdoors."
Prof Lye was responding to a suggestion by Workers' Party MP Jamus Lim that Singapore should move towards relaxing mask-wearing rules in certain outdoor settings.
In a Facebook post on Tuesday (Sept 21), Associate Professor Lim said masks work in containing transmission and remain an important tool in Singapore's fight against Covid-19.
But he said the risk of transmission outdoors is "far lower" compared with indoors.
Having to wear a mask all the time can contribute to mask fatigue, which can in turn increase the risk of indoor transmission, he argued.
"Keeping the mask on constantly is stifling, and all the more so in our hot and humid climate," said Prof Lim.
"Not only that, it often leads to people ripping their masks off once indoors to obtain some relief. I'm sure we all know of co-workers who unmask, especially in smaller meeting rooms and offices."
This behaviour is "the wrong way around", given the higher risk of transmission indoors, he added.
"My view is that we should move toward relaxing our outdoor masking rules, except perhaps where there is still close interpersonal contact, like in markets and other crowded spaces, but insist on strict adherence indoors," said the Sengkang GRC MP.
"More generally, we can evolve our Covid-19 policy to pay more attention to indoor air quality, especially when we treat the disease as endemic."
Experts who spoke to The Straits Times agreed that the transmission rate in outdoor settings is generally lower than in indoor settings, but they noted that this depends on several factors and it can be complicated to apply such a policy.
Prof Lye noted that outdoor transmission can occur in crowded settings where people congregate, but he added that it is difficult or impossible to define crowdedness.
"If you are alone in the forest, you will not get Covid-19, but Singapore is generally very crowded."
Dr Tan Teck Jack, who is chief executive of Northeast Medical Group and holds a master's degree in public health, said the authorities have to weigh the risks when formulating any policy, as well as other factors like ease of implementation and whether the policy is simple and easily understood.
The emergence of the Delta variant has also complicated matters. The variant is known to be more transmissible but it is still unclear how lethal it is compared with other variants, Dr Tan noted.
"I would err on the side of caution and keep the mask policy intact," he added.
"As a whole, we are very law-abiding in Singapore. We should continue to support those who abide by the rules."
Infectious diseases specialist Leong Hoe Nam said one reason outdoor transmission has not been consistently proven could be the greater difficulty of tracking people's movements outdoors.
"There is no SafeEntry QR code on every corner and street. If there was, we may find that outdoor transmission occurs significantly. Absence of evidence is not evidence of absence," Dr Leong said.
He also noted how the United States rescinded its mandate on outdoor mask-wearing for vaccinated people in late April, only for states like Oregon to reimpose the rule last month after a surge in cases driven by the Delta variant.
Prof Lye was concerned that loosening mask requirements outdoors could weaken the public's mask-wearing habit in general.
"A person who does not wear a mask outdoors is more likely to forget to wear it indoors, as a matter of human nature and habits."
He also said mask-wearing remains one of the most effective and cheapest ways of reducing one's risk of contracting Covid-19 and other respiratory viruses like influenza.
"I will continue to wear my mask indoors and in crowded outdoor environments even after the Government eventually relaxes the rules. It is easy and it protects me."