13.FEB.2020 7 MIN READ | 7 MIN READ

Dr Leong Hoe Nam, infectious disease specialist at Mount Elizabeth Novena Hospital, answers questions you may have on the COVID-19 novel coronavirus.

Last updated on 23 June 2021

Dr Leong Hoe Nam is an infectious disease specialist practising at Mount Elizabeth Novena Hospital, Singapore. He had first-hand experience managing infectious diseases such as the Severe Acute Respiratory Syndrome (SARS) coronavirus and the Influenza A (H1N1) virus. Here’s what he says about the novel coronavirus in his Facebook Live interview with ONE FM 91.3.

What is the COVID-19 novel coronavirus?

The COVID-19, also known as SARS-CoV-2, is a coronavirus like the Middle East Respiratory Syndrome (MERS) and SARS coronaviruses. However, it is distinct from SARS – this means that even if you have been exposed to SARS previously, you can still get the novel coronavirus.

The SARS-CoV-2 is highly pathogenic (causes illness), virulent (has harmful effects) and spreads very quickly. Originating from Wuhan city, China, infections have now been reported around the world. There is reason to believe that the novel coronavirus may have its origins in bats or pangolins, before spreading between humans. The exact source is still unclear.

What are its symptoms?

Symptoms covid coronavirus wuhan virus

Symptoms of the virus include:

  • Fever
  • Cough
  • Sore throat
  • Muscle aches
  • Breathlessness – At about day 5 – 7 of having a fever, patients have reported feeling increasingly breathless.
  • Anomsia (loss of sense of smell)

How is it transmitted?

Transmission of the COVID-19 virus happens via droplets and contact. There is a possibility of airborne transmission, however there is limited consensus on how infectious this mode of transmission may be. 

Airbone: Evidence shows that small, fine droplets can remain suspended in the air up to 3 hours. The risk of transmission would be greatest within 2m of an infected person, where the concentration is greatest, and diminishes with distance. Airborne exposure would also be affected by factors such as airflow and environmental factors such as temperature, humidity and exposure to sunlight. 

A person can get infected through the spit of an infected person landing on them (within 2m)

Contact: A person can get infected through touching a surface (eg. a door handle or table) with infectious secretions. In both cases, one can be infected by the virus coming in contact with his eyes, nose or mouth.

It is still uncertain how quickly the coronavirus spreads between humans. The chances of the virus spreading through transient contact with an infected person are low (eg. walking past someone, touching someone briefly and washing hands afterwards). However, prolonged close contact with an infected person may increase the chances of the virus spreading. For instance, being in close proximity with an infected person who is an exuberant speaker for an extended amount of time in an air-conditioned room.

Significantly, recent scientific data suggests that transmission may occur prior to the onset of symptoms. We call these pre-symptomatic or asymptomatic transmission.

How can we prevent the spread of the coronavirus?

Prevent spread virus coronavirus
  • Wash your hands regularly with soap and water. If you do not have soap at hand, wash your hands with water. Water itself can kill the virus.
  • Avoid touching any part of your face without first washing your hands. Live by Dr Leong’s mantra – ‘your face is sacred’.
  • Wipe down surfaces around you with detergent and water if you are concerned about contaminated surfaces.
  • Wear a mask when you leave the house. As we now know that asymptomatic/pre-symptomatic individuals may spread infection, we encourage everyone to wear a face mask or surgical or medical mask to prevent cross transmission between infected and uninfected individuals. Face masks, which are non-medical, may be used in public and community settings and should have 2 – 3 layers of fabric – a water-repellent outer layer, filter to remove particulates and absorbent inner layer. Surgical or medical masks should be used in clinical settings where you may be exposed to an infected or potentially infected individual, including visits to clinics and hospitals. Ensure you are wearing your mask properly, and that your mask fits snugly against your face. You can refer to the Frequently Asked Questions (FAQs) at the end of this article for instructions on how to do so.
  • Seek treatment if you are feeling unwell. While you can recover from a cold on your own, you are advised to see a doctor immediately if you suspect you have the novel coronavirus. If you are experiencing breathing difficulties, you may have pneumonia, which is a lung infection. In these cases, it is important to see a doctor as soon as possible for an accurate diagnosis and timely treatment.
  • Avoid crowded places with big groups of people. Given recent cases of local transmission of the virus, it is important to limit contact with large groups of people, and be mindful of who you are coming in contact with.

Is there a cure for the COVID-19 novel coronavirus?

There is currently no cure for COVID-19 but there are safe and effective vaccines available. The Pfizer BioNTech and Moderna COVID-19 vaccines are both approved by the HSA for use in Singapore under the Pandemic Special Access Route (PSAR).  The Pfizer BioNTech vaccine is approved for children aged 12 years and above while the Moderna vaccine is approved for individuals 18 and above. 

The Sinovac vaccine is also approved for use under the Special Access Route, hence it is not subsidised and may only be administered by private healthcare providers to individuals who wish to have it.   

Learn more about the COVID-19 vaccine here.

Currently, the treatment for infected individuals is supportive care. This means that the virus symptoms are managed by providing good nutrition and hospital care to let the patient recover. This is likely to work for a vast majority of patients. While more information needs to be gathered, Dr Leong surmises that the recovery period for patients can take at least 10 – 14 days.

Scientists are working on developing a cure for the virus. While there are ongoing studies on using HIV treatment to treat the virus, these are still undergoing trials and deemed experimental. Drugs like remedesivir and favipiravir are currently on trial to demonstrate effectiveness. The drug hydroxychloroquine has been proven ineffective in patients with COVID-19.

Here are some other questions about the virus that you may have, as answered by Dr Leong:

Frequently Asked Questions

Q: Which mask should I use? Can I use a plain white mask, or the N95 mask?

Dr Leong: You should wear the blue and white surgical masks. The plain white masks are very thin compared to the blue and white surgical masks, which have 3 layers. The first outer layer is for general protection against spills. The second layer acts as a filter, and the inner layer is for your comfort when you wear the mask.

While the N95 mask works as a protection measure as well, I would discourage people from wearing it. This is because wearing the N95 mask can cause a lot of discomfort, and you may end up touching your face a lot as you adjust the mask, which should be avoided.

Face masks should be used in public and community settings while surgical or medical masks should be used in clinical settings where you may be exposed to an infected or potentially infected individual, including visits to clinics and hospitals. 

Q: What is the right way to wear my mask?

Dr Leong: When wearing a mask, the blue side of the mask should be facing the outside, and the white side facing inside. There is no reason to wear it the other way round – doing so may trap things within the folds on the blue side.

Strap the sides over your ears first. Next, pull the top of the mask up to cover your nose, and ensure that the bottom of the mask covers below your chin. Thereafter, pinch the metal piece on your nose bridge to ensure the mask doesn’t slip from your face.

Q: How long can I use my mask for?

Mask wear time effective
Dr Leong: It depends. If your mask is wet, this means its filter component has been breached, and is no longer effective. Throw the mask away.

However, if your mask is relatively clean and dry after use, you can take it off and put it into a sealable bag, to be reused again.

At the end of the day, I would encourage you to discard it once it has been used. When disposing of your mask, make sure to wrap it up with a tissue paper or bag, to ensure that germs on the mask do not spread to other surfaces.

Q: If I feel unwell, how safe is it to visit a clinic during this period?

Dr Leong: If you have to visit a clinic, make sure you wear a mask and wash your hands with soap and water. Avoid touching your face.

Q: With medical science at its peak, why wasn’t a vaccine prepared earlier for a virus like this?

Dr Leong: If you look at the fecal matter of bats, there are thousands of coronavirus. No one knows which strain will go pandemic. Even if vaccines are prepared for all the coronavirus strains, the viruses can mutate easily and turn into a completely new virus, rendering the vaccines useless. It is also nearly impossible to predict how these viruses will mutate.


Watch Dr Leong’s interview with ONE FM 91.3 in full.


Article contributed by Dr Leong Hoe Nam, infectious disease specialist at Mount Elizabeth Novena Hospital


2019 Novel Coronavirus (2019-nCoV) Situation Summary. (2020, February 7). Retrieved February 11, 2020, from https://www.cdc.gov/coronavirus/2019-nCoV/summary.html Beall, A. (2020, February 10). The global fight against coronavirus. Retrieved February 11, 2020, from https://www.bbc.com/future/article/20200210-coronavirus-finding-a-cure-to-fight-the-symptoms

Steve, Y. T. Y. (2020, January 31). An Explanation of Pneumonia & the Wuhan Novel Coronavirus. Retrieved February 11, 2020, from https://www.mountelizabeth.com.sg/healthplus/article/pneumonia-and-coronavirus

(7 May 2021) What you need to know about masks. Retrieved 15 June 2021, from https://www.hsa.gov.sg/consumer-safety/articles/what-you-need-to-know-about-masks 

 (7 May 2021) SARS-CoV-2 Transmission. Retrieved 15 June 2021 from https://www.cdc.gov/coronavirus/2019-ncov/science/science-briefs/sars-cov-2-transmission.html 

(4 June 2021) FAQS - SAFETY AND EFFICACY OF THE COVID-19 VACCINE. Retrieved 14 June 2021 from https://www.moh.gov.sg/covid-19/vaccination/faqs/faqs---safety-and-efficacy-of-the-covid-19-vaccine 

(5 June 2021) COVID-19 VACCINATION. Retrieved 14 June 2021 from https://www.moh.gov.sg/covid-19/vaccination

(5 June 2021) Frequently Asked Questions (FAQs) on COVID-19 Vaccination. Retrieved 14 June 2021 from https://www.moh.gov.sg/covid-19/vaccination/faqs 

(7 June 2021) Singapore's expert panel on Covid-19 vaccination continues to recommend Pfizer, Moderna. Retrieved 14 June 2021 from  https://www.straitstimes.com/singapore/health/singapores-expert-panel-on-covid-19-vaccination-continues-to-recommend-pfizer

 (n.d.) How Does Coronavirus Spread? Retrieved 15 June 2021 from https://www.webmd.com/lung/coronavirus-transmission-overview#1
Leong Hoe Nam
Infectious Disease Specialist
Mount Elizabeth Hospital

Dr Leong Hoe Nam is an infectious disease specialist practising at Mount Elizabeth Novena Hospital, Singapore. His clinical interest is in the treatment of complex infectious diseases such as tuberculosis, HIV and surgical complications, especially for transplant patients and patients with multi-drug resistant organisms.