SINGAPORE - There is no need for people who are well to use masks. As for those with respiratory symptoms such as a cough or runny nose, a surgical mask will do and an N95 mask is not necessary, stressed the chief of Singapore's infectious diseases centre.

Professor Leo Yee Sin, executive director of the National Centre for Infectious Diseases (NCID), said surgical masks can help block large-particle droplets from reaching others.

"For people without any respiratory symptoms, there is no need to put on a surgical mask. We need to have a community effort - for those individuals who display symptoms, put on a mask. This will give safety margins to many of the people without symptoms around them," Prof Leo told reporters at Tan Tock Seng Hospital (TTSH) on Saturday (Jan 25).

She was speaking on the sidelines of a visit by Health Minister Gan Kim Yong to the hospital on the first day of Chinese New Year.

Prof Leo explained that surgical masks, which have two layers, are well-designed to reduce exposure of the wearer's respiratory secretions to others.

"The inner layer is able to absorb many of the secretions that we release from our respiratory system. The masks are therefore able to capture droplets we produce when we cough, sneeze or talk," she said.

Stressing that most viruses spread through the transmission of droplets, Prof Leo added: "There are large particles that you have to catch and surgical masks are good enough to do that."

In contrast, the N95 mask is a specially-designed respirator used in environments such as hospitals.

"In healthcare settings, you use the N95 mask because it's a very concentrated area where you take care of patients. All healthcare workers have to go through fittings to make sure a particular brand of N95 can fit well onto their faces and that there are no gaps in between," said Prof Leo.

N95 masks, which are tighter fitting, are designed to effectively filter airborne particles. They have been used in Singapore during haze situations.

Masks have been flying off the shelves here since the Wuhan virus outbreak.

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Checks by The Straits Times at five pharmacies on Wednesday found that four had run out of N95 masks and three were out of surgical masks.

Three people in Singapore are confirmed to have the Wuhan virus, as at the last update by MOH on Friday afternoon.

The first confirmed case is a 66-year-old man from Wuhan who is here on holiday. He is currently in stable condition at the Singapore General Hospital (SGH).

His 37-year-old son who was travelling with him has since been confirmed to have the virus too. He is also at SGH and in stable condition.

In addition, another Chinese tourist - a 53-year-old woman from Wuhan who came separately from the two men - has been confirmed as having the virus. She is warded at the NCID and her condition is stable.

Prof Leo said: "This is still a very new virus and we are still in the learning curve. The important thing is to understand it's a disease that can be transmitted between humans. We therefore have to observe personal hygiene to protect ourselves and the community."

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Speaking to the media at TTSH, Mr Gan urged the public to observe personal hygiene while enjoying the Chinese New Year festivities.

He also thanked all healthcare workers who are on duty during the festive period.

"Many of them have sacrificed their festive holidays. Instead of being with their family members, they have come back to work in order to take care of our patients and loved ones," said Mr Gan.

Many healthcare workers, including private general practitioners (GPs), are at the front line of virus outbreaks and play an important role in the detection of suspected cases, the minister added.

MOH has been working with GPs, clinics and hospitals to ensure that adequate protective gears are provided to them, he said.

Mr Gan visited more than 40 staff members and patients in several wards, handing out red packets and oranges.

He also joined more than 50 TTSH staff in a lo hei toss.

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