One of the most frequently debated topics since the COVID-19 outbreak is whether masks worn by the general public are useful. And if so, who do they protect – the wearer or the people around.

The second question is easier to answer. 

"Evidence for using masks to protect yourself from getting the infection was and remains very weak. So, the major use of such masks is to protect others from you spreading infection to them," explained Dr. Piotr Chlebicki, an infectious disease specialist at Singapore's Mount Alvernia Hospital.

"When the surgical masks were first used, they were used to protect patients from getting infection from their surgeon, not for surgeons to be prevented from getting infections from their patients," Dr. Chlebicki elaborated.

"And when they are used that way it only works when everybody uses them," he added.

With regards to whether masks can help against the spread of COVID-19, the opinion seems to be shifting in favor of donning masks based on new scientific evidence.

"Science has actually changed the way we view this virus. In comparison, all respiratory viruses including respiratory influenza virus may transmit one day before the onset of the illness. However, for the case of COVID-19, we realize that the virus may spread much before the onset of symptoms," highlighted infectious disease expert Dr. Leong Hoe Nam.

Dr. Leong, who practices at Singapore's Mount Elizabeth Novena Hospital, underlined the fact that something as harmless as talking could cause the infection to spread.

"Virus may come out of the nose and the throat and as you speak, the viruses may come out, as you cough and sneeze, and all this can be done very innocuously, very harmlessly."

Scientists from Singapore's Agency for Science, Technology and Research (A*STAR), together with doctors from the Singapore General Hospital's Department of Infectious Diseases and the Department of Respiratory and Critical Care Medicine, recently conducted an experiment to demonstrate the propagation of airborne water droplets.

A spokesperson for A*STAR told CGTN that these "ultra-small droplets, which can travel with high speeds and are typically invisible to the naked eye, can be observed by illuminating them with a laser sheet and capturing them on a high-speed camera."

"The scientists were able to establish that correctly wearing a mask, especially with proper fit, can greatly reduce the amount of droplets expelled and hence the potential for disease transmission."

Similar information prompted the Singapore government to make masks mandatory for its residents as soon as they leave their homes. The new guidelines also require people to wear masks when walking or during less strenuous exercise.

While most Singaporeans accepted the reasoning behind wearing masks in crowded places, there were some who questioned the decision to enforce this rule in open spaces.

"Singapore is quite built up, even if you walk out for a short distance, you could be inside an indoor area very quickly. If you try to separate between indoor and outdoor, there is going to be a lot of confusion. For easier implementation, it makes more sense to just wear a mask the moment you leave the house," Dr. Leong said. 

Another area of concern is that the viral load for COVID-19 is far higher than the regular flu.

"With the amount of virus that flies out, it will be a lot. It is about 1,000 times more than influenza. Even with a dilution of the air, the 1,000 times extra may not be sufficiently diluted. Such that the virus can still land on the other person and get infected," explained Dr. Leong.

Despite aggressive contact tracing, testing and isolating, the number of local transmissions has seen a steady rise over the last few weeks in the island nation, prompting medical experts to hypothesize that there could be asymptomatic carriers of the virus within the community.

"Throwing so many measures and so much effort on it, Singapore was not able to control it (local transmission). Science revealed that there probably were asymptomatic or mildly symptomatic individuals who are sharing this virus on to the community. Hence the need to wear a mask to prevent transmission," underscored Dr. Leong.

Meanwhile, in an effort to ensure that surgical or N95 masks don't run out and stockpiles remain for frontline or healthcare personnel, the Singapore government distributed reusable masks to all its households.

While reusable masks are not as effective as surgical ones, they can still help reduce transmission if worn correctly and kept clean and dry.

"If the mask is worn for a long time and it becomes wet, then it simply becomes unhygienic and I guess after something like a day it has to be disposed of. And when it comes to reusable masks, cloth masks, then after wearing them for one day it has to be washed," said Dr. Chlebicki.

"I would use a gentle soap, soak it inside water and wash it, thereafter gently wring it and then leave it out to dry, air dry and not sun dry," added Dr. Leong.

All the medical experts CGTN spoke to agreed that masks, whether surgical or reusable, are essential to reducing community transmission of COVID-19. However, all of them emphasized that usage of masks cannot replace safe distancing and personal hygiene, but in fact the two should go hand-in-hand, if we are to succeed in checking the spread of the virus.