Frequently Asked Questions on Coronavirus Disease 2019 (COVID-19)

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1. What is a novel coronavirus?
2. What is Coronavirus Disease 2019 (COVID-19)?
3. What are the symptoms of COVID-19?
4. What is the mode of transmission of COVID-19?
5. What is incubation period? How long is it for COVID-19?
6. What is the treatment for COVID-19?
7. How to prevent COVID-19?
8. What are the advice on health measures for persons tested positive?
9. What is the function of a mask?
10. Can young children wear a face mask?
11. What are the other measures to prevent respiratory tract infection other than wearing a mask?
12. After cleaning the hands with water and liquid soap, how should the faucet be turned off?
13. If there is no water and liquid soap, can I use alcohol-based handrub instead?
14. What are cough manners?
15. Why is it important to properly maintain drainage pipes and regularly re-fill U-traps?
16. Should consumers sanitise food packaging?
17. What to take note of when using disinfectants?

1. What is a novel coronavirus?

Coronaviruses are a large family of viruses found in both animals and humans. Some infect people and are known to cause illness ranging from the common cold to more severe diseases such as Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS).

2. What is Coronavirus Disease 2019 (COVID-19)?

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the SARS-CoV-2 virus.

3. What are the symptoms of COVID-19?

The most common symptoms of COVID-19 include fever, chills and sore throat. Other symptoms include severe fatigue, loss or change of sense of taste and /or smell, nasal congestion, conjunctivitis, headache, muscle or joint pain, skin rash, nausea or vomiting, diarrhea and dizziness. Some people may only have very mild or non-specific symptoms, while some may develop severe symptoms like shortness of breath, chest pain or confusion.

Complications may include respiratory failure, acute respiratory distress syndrome (ARDS), sepsis and septic shock, thromboembolism, and/or multi-organ failure including injury of the heart, liver or kidneys. There are reports that children and adolescents with COVID-19 may develop a rare but serious condition known as multisystem inflammatory syndrome in children (MIS-C), leading to multiorgan failure and shock.

People over age 60 and those with existing medical conditions including hypertension, heart and lung problems, diabetes, obesity, cancer and pregnancy are at higher risk of developing serious illness.

Post COVID-19 condition, commonly known as long COVID, can affect anyone exposed to SARS-CoV-2, regardless of age or severity of original symptoms. The World Health Organization (WHO) defines long COVID as the continuation or development of new symptoms 3 months after the initial SARS-CoV-2 infection, with these symptoms lasting for at least 2 months with no other explanation.

Common symptoms of long COVID include fatigue, shortness of breath, cognitive dysfunction, headache, chest pain, joint pain and may have an impact on everyday functioning. Studies showed that approximately 10-20% of people infected with COVID-19 may go on to develop symptoms that can be diagnosed as long COVID. WHO recommends that protection from long COVID means protecting yourself and others from COVID-19 infection in the first place. Some simple and proven measures can help to this including:

• Taking up offers of COVID-19 vaccines/boosters
• Wearing well-fitted masks
• cleaning hands regularly
• ensuring indoor spaces are well ventilated

For more information on long COVID, please refer to the long COVID page under the thematic website of COVID-19.

4. What is the mode of transmission of COVID-19?

Mode of transmission includes through respiratory droplets, contact of contaminated surfaces or objects, short-range aerosol or short-range airborne transmission. The virus can also spread in poorly ventilated and/or crowded indoor settings.

5. What is incubation period? How long is it for COVID-19?

The "incubation period" means the time between catching the virus and beginning to have symptoms of the disease. Incubation periods may differ by SARS-CoV-2 variant. Most estimates of the incubation period range from 1 to 14 days, and some variants, such as the Omicron variant, may have even shorter incubation period of around 3 days.

6. What is the treatment for COVID-19?

Treatment includes supportive therapy, symptomatic treatment, antiviral agents and Chinese medicine.

7. How to prevent COVID-19?

COVID-19 vaccination

• Members of the public are advised to take note of the latest recommendations on the use of COVID-19 vaccines in Hong Kong to protect themselves from serious outcomes of COVID-19.
• For details on COVID-19 vaccination, please refer to thematic web page for COVID-19 Vaccination Programme: https://www.chp.gov.hk/en/features/106934.html

Health advice

Members of the public are also advised to maintain strict personal and environmental hygiene at all times for personal protection against infection and prevention of the spread of the disease in the community:

• The wearing of mask is advised for the following situations -

1. any persons with fever or respiratory symptoms;
2. any persons who are visiting or working in high risk places such as residential care homes for the elderly, residential care homes for persons with disabilities, and clinical areas of healthcare facilities; and
3. high risk persons (e.g. persons with underlying medical conditions or persons who are immunocompromised) who are going to crowded places such as public transport.
4. when an increasing trend in activity of respiratory viruses including SARS-CoV-2 virus is expected, high risk persons are recommended to wear a surgical mask when visiting public places, while the public should also wear a surgical mask when taking public transportations or staying at crowded places.

• It is important to wear a mask properly, including perform hand hygiene before wearing and after removing a surgical mask. For details on proper mask wearing, please visit CHP website at www.chp.gov.hk/files/pdf/use_mask_properly.pdf;
• Avoid touching your eyes, mouth and nose before washing hands;
• Perform hand hygiene frequently, especially before touching one's mouth, nose or eyes; before eating; after using the toilet; after touching public installations such as handrails or door knobs; or when hands are contaminated by respiratory secretions after coughing or sneezing;
• Cover your mouth and nose with tissue paper when sneezing or coughing. Dispose of soiled tissues into a lidded rubbish bin, then wash hands thoroughly;
• Wash hands with liquid soap and water, and rub for at least 20 seconds. Then rinse with water and dry with a disposable paper towel or hand dryer. When the hands are cleaned, do not touch the water tap directly again (for example, using a paper towel to wrap the faucet before turn it off). If hand washing facilities are not available, or when hands are not visibly soiled, performing hand hygiene with 70 to 80% alcohol-based handrub is also an effective alternative;
• After using the toilet, put the toilet lid down before flushing to avoid spreading germs;
• Maintain good indoor ventilation;
• Home should be cleaned thoroughly at least once per week with 1 in 99 diluted household bleach (mixing 10 ml of bleach containing 5.25% sodium hypochlorite with 990 ml of water), leave for 15 - 30 minutes and then rinse with water. For metallic surface, disinfect with 70% alcohol. For more information on the use of bleach, please visit the following webpage: https://www.chp.gov.hk/files/pdf/the_use_of_bleach.pdf;
• If places are contaminated by respiratory secretions, vomitus or excreta, use strong absorbent disposable towels to clean up the visible matter. Then disinfect the surface and the neighbouring area with appropriate disinfectant. For nonmetallic surface, disinfect with 1 in 49 diluted household bleach (mixture of 10ml of household bleach containing 5.25% sodium hypochlorite solution with 490ml of water), leave for 15 to 30 minutes, and then rinse with water. For metallic surface, disinfect with 70% alcohol;
• Maintain drainage pipes properly and regularly (about once a week) pour about half a litre of water into each drain outlet (U-traps) to ensure environmental hygiene;
• Build up good body resistance and maintain healthy lifestyle. This can be achieved through balanced diet, regular exercise and adequate rest and
• Do not smoke and avoid alcohol consumption.

8. What are the advice on health measures for persons tested positive?

Persons tested positive for COVID-19 should take heed of the health advice below:

• Persons who are at higher risk (e.g. immunosuppressed people, older people, people with underlying medical conditions) and persons who developed obvious symptoms are advised to seek prompt medical advice;
• Persons who are symptomatic are advised to stay at home and avoid going out.  Persons who are asymptomatic can go out at their own will or go to work.
• Students who are symptomatic should not attend schools;
• Infected persons are advised to wear well-fitting surgical masks, KF94 masks, KN95 masks or respirators (such as N95 respirators) during the first five days after testing positive. They should also avoid contact with persons who are at higher risk, contact with others in mask-off situation (e.g. share table with others for meal), going to crowded places and mass gatherings;
• Closely monitor health condition and seek medical advice promptly if symptoms arise or getting worse;
• Keep your home well ventilated by having windows opened as far as feasible; and
• Pay attention to personal and environmental hygiene at all times. Clean and disinfect the shared items and facilities (e.g. toilet) at home frequently and after use

9. What is the function of a mask?

Face mask provides a physical barrier to fluids and large particle droplets. Surgical mask is a type of face mask commonly used. Choose an appropriate size to completely cover nose, mouth and chin without gaps. Attain good seal with the face by minimising air leak from edges.

Most surgical masks adopt a three-layer design which includes an outer fluid-repelling layer, a middle layer serves as a barrier to germs, and an inner moisture-absorbing layer. Mask without the above functions is not recommended as it cannot provide adequate protection against infectious diseases transmitted by respiratory droplets. Masks with exhalation valve or vents which allow exhaling air to escape should not be used due to the fact that exhaled air are unfiltered and may pose a risk to surrounding people if the wearer is infected with COVID-19 or other respiratory infectious diseases.

The general indications for wearing a surgical mask include:

• To protect ourselves: When taking care of person with respiratory infection; or visiting hospitals or clinics during peak season for respiratory infectious diseases;
• To prevent the spread of infection to others: When having respiratory symptoms, e.g. fever, runny nose, cough or sneeze.

10. Can young children wear a face mask?

Choose the appropriate mask size. Child size is available for selection as indicated:

• Face mask (including surgical masks and cloth face coverings) is not recommended for children under the age of 2 years without supervision;
• For newborns and young children under 2, there would be a chance of suffocation or other health risks if face mask is not properly used. In addition, young children like to touch or pull the mask on their face which increase the chance of infection;

11. What are the other measures to prevent respiratory tract infection other than wearing a mask?

The following preventive measures, apart from wearing a well-fitted surgical mask, should be emphasised:

• Hand hygiene is the single most important measure of reducing the spread of diseases. Members of the public should perform hand hygiene properly and frequently, especially before touching eyes, nose and mouth; before eating or preparing food; after using the toilet; when hands are contaminated by respiratory secretions, e.g. after coughing or sneezing; and after touching public installations or equipment, such as escalator handrails, elevator control, panels or door knobs.
• Wash hands with liquid soap and water when hands are visibly soiled or likely contaminated with blood and body fluid. When hands are not visibly soiled, hands could be cleaned with 70 to 80% alcohol-based handrub;
• Maintain respiratory etiquette and cough manners;
• Stay at home if got sick and minimise contact with others;
• Stay away from possible sources of infection and avoid contact with the infected persons by minimizing unnecessary social contacts and avoid visiting crowded places or shorten the length of stay whenever possible, especially for persons at a high risk of having infection-related complications, e.g. pregnant women or persons with chronic illnesses

12. After cleaning the hands with water and liquid soap, how should the faucet be turned off?

When the hands are cleaned, do not touch the water tap directly again. For example, one may use a paper towel to wrap the faucet before turn it off.

13. If there is no water and liquid soap, can I use alcohol-based handrub instead?

If your hands are not visibly soiled, you can use 70 to 80% alcohol-based handrub. It can effectively prevent cross transmission of infectious diseases via hands.

The hand rubbing technique of using alcohol-based handrub is similar to hand washing. Use sufficient amount, around 3 to 5 ml of alcohol-based handrub to cover all surfaces of your hands. Rub our palms, back of hands, finger webs, back of fingers, thumbs, finger tips, and wrists. Rub hands for at least 20 seconds until your hands are dry. Let the alcohol dry on your hands, do not wipe it off with paper towel. Check the expiry date of alcohol-based handrub before using.

14. What are cough manners?

Cover your mouth and nose with tissue paper when sneezing or coughing. Dispose of soiled tissues into a lidded rubbish bin, then wash hands thoroughly. If tissue paper is not available, you can cover your mouth and nose with your blouse or upper sleeve.

15. Why is it important to properly maintain drainage pipes and regularly re-fill U-traps?

U-traps serve to stop foul smells and unhygienic substances (including bacteria and viruses) in the drainage system from entering living areas. Defective or dried U-traps could negate this important function.

Pour half a litre of water into each drain outlet every week. Besides, one should regularly inspect their drainage pipes, U-traps and sanitary fittings and arrange immediate repair if damage is found.

16. Should consumers sanitise food packaging?

The risk of acquiring the novel coronavirus through food packaging is very low. In fact, contaminated hands play a significant role in facilitating indirect contact transmission by transferring the infectious virus from one surface to another and even into one’s body. Instead of food packaging, transmission is more likely to happen in contact with certain high-touch points, such as door handles, handles of the shopping trolleys and water taps – the more frequently being touched by different people the higher the risk that it becomes contaminated. Therefore, while some people may still opt to disinfect food packaging surfaces with common household disinfectants such as alcohol-based wipes or sprays if needed, it is more important for people to wash their hands thoroughly, especially before touching eyes, nose and mouth, after returning home from grocery shopping, and after handling and storing purchased products.

Points to note if disinfection of packaging would be performed:

• Disinfectant should (i) Be proofed to be effective against SARS-CoV-2; (ii) Compatible to the packaging material; (iii) Used according to the manufacturer recommendations.
• Perform hand hygiene after cleaning and disinfection of the packaging.

17. What to take note of when using disinfectants?

Disinfectant and relevant equipment should be used properly. Improper use may lead to adverse health effects and environmental contamination.

Follow the manufacturer’s instructions to ensure that disinfectant and relevant equipment are handled and used safely and effectively. Pay particular attention to information about application and safety, such as the recommended use, concentration and contact time, items and surfaces compatible with the disinfectant, stability of the product, hazard warning, storage method and personal protective equipment required when using the product. Keep disinfectant out of reach of children and pets. To prevent accident, do not pour disinfectants into other containers with different labels.

Improper use of disinfectant and relevant equipment may lead to adverse health effects to users. The adverse health effects caused by disinfectants are dependent on several factors, such as chemical ingredients of disinfectant, exposure duration and concentration, route of exposure, the individual state of health, and environmental conditions. In general, direct contact to disinfectant may cause irritations on eye, skin and respiratory tract. It may affect the lung if inhaled, or even fatal if used incorrectly.

Keep well ventilated while using disinfectant.

Spraying of people with disinfectants is not recommended. This practice could be harmful to health and would not reduce an infected person’s ability to spread the virus.

In indoor spaces, routine application of disinfectants to environmental surfaces via spraying is generally not recommended because it is ineffective at removing contaminants outside of direct spray zones and can cause eye, respiratory, and skin irritation and other toxic effects. If disinfectants are to be applied, these should be via a cloth or wipe which is soaked in the disinfectant.

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