Those who are on five days' medical leave should avoid contact with their elderly family members "at all costs", warned the National Centre for Infectious Diseases' (NCID) executive director Leo Yee Sin yesterday.

This is because the elderly are vulnerable to virus infections, including Covid-19, she said.

Those with symptoms of acute respiratory illness who are prescribed five days' medical leave at home should also try to avoid contact with all family members of any age, even at mealtimes, said Professor Leo.

She added that if it is absolutely necessary to interact with others at home, those on medical leave should put on a surgical mask.

Separately, they should also take care of their personal hygiene, washing their hands frequently with water and soap or using hand sanitiser.

They should keep their surroundings clean, and preferably use a dedicated toilet which others in the house do not use.

If this is not possible, the toilet they use must be kept clean.

Prof Leo said: "This is necessary as we learn more about Sars-CoV-2 that causes Covid-19."

The virus can be spread through both direct and indirect droplet transmission, she added.

This could take place through close face-to-face contact within 1m to 2m of an infected person, or through interaction with a contaminated environment or contaminated objects.

Prof Leo said: "NCID would like to stress that anyone who has acute respiratory illness, regardless of severity, should put on a surgical mask and seek early medical consultation."

The common symptoms of acute respiratory illness include fever, cough, sore throat and a runny nose.

"If the doctor provides five days' rest at home, please adhere closely to that - rest at home and do not leave the house," added Prof Leo.

Her comments came a day after the Ministry of Health updated the Infectious Diseases Act, stating that those with acute respiratory symptoms who are given a five-day medical certificate by a doctor must not leave home from the day the MC is given, except to seek medical attention. Those who fail to comply can be fined up to $10,000, jailed for up to six months, or both.

Similar penalties apply to those who intentionally sit less than 1m away from another person in a public place, on a fixed seat marked not to be occupied, or stand in a queue less than 1m away from another person.