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Coronavirus Disease 2019 (COVID-19)

Coronavirus Disease 2019 (COVID-19)

20 July 2022

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Causative agent

“Coronavirus disease 2019 (COVID-19)” is the disease caused by a new coronavirus called “SARS-CoV-2”.

Clinical features

The most common symptoms of COVID-19 include fever, dry cough and fatigue. Other symptoms include loss of taste or smell, nasal congestion, conjunctivitis, sore throat, headache, muscle or joint pain, skin rash, nausea or vomiting, diarrhea, chills or 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 of older age and those having underlying medical problems (e.g. hypertension, heart and lung problems, diabetes, obesity or cancer) are at higher risk of developing serious illness.

According to the information from the World Health Organization (WHO), approximately 10-20% of people may continue to experience mid- and long-term effects of COVID-19, which are collectively known as “Post COVID-19 condition,” or “Long COVID”. Common symptoms of long COVID include fatigue, shortness of breath, cognitive dysfunction, headache, pain (e.g. chest pain, joint pain) and may have an impact on everyday functioning. There may be multi-organ effects or autoimmune conditions particularly in children. Symptoms may be new onset following initial recovery from an acute COVID-19 episode or persist from the initial illness. Symptoms may also fluctuate (change from time to time) or relapse (return of symptoms after period of improvement) over time. Although it is still unclear how long the symptoms may last, current research suggests that patients can improve with time. Some studies reported that long COVID is found more often in people who had severe COVID-19 illness, but anyone (including those with mild illness) can experience this condition after infected with COVID-19. According to WHO, COVID-19 vaccination can reduce incidence of long COVID. Some studies also suggested vaccinated persons are less likely to develop long COVID even they get infected, compared to the unvaccinated.

Mode of transmission and incubation period

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. 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.

Management

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

Prevention

COVID-19 vaccination

  • COVID-19 vaccines are effective to protect people against COVID-19 disease, in particular severe illness and death.
  • Vaccination is one of the tools in the overall public health response to COVID-19. The combination of non-pharmaceutical interventions (NPIs) with vaccination will allow for maximum protection against the virus.
  • With COVID-19 vaccines deployed, there is a need to continue NPIs, including social distancing, good hand hygiene and wearing a mask in public, to reduce the risk of virus transmission. NPIs should continue to be followed by vaccinated individuals, as well as those who have not yet been vaccinated.
  • For details on COVID-19 vaccination, please refer to thematic website for COVID-19 Vaccination Programme: www.covidvaccine.gov.hk

Health advice

Members of the public are urged to go out less and reduce social activities such as meal gatherings or other gatherings, and maintain appropriate social distance with other people as far as possible.

To maintain at all times strict personal and environmental hygiene is key to personal protection against infection and prevention of the spread of the disease in the community:

  • Well-fitted surgical mask can prevent transmission of respiratory viruses from ill persons. It is essential for persons who are symptomatic (even if having mild symptoms) to wear a well-fitted surgical mask;
  • Wear a surgical mask when taking public transport or staying in crowded places. It is important to wear a mask properly, including hand hygiene before wearing and after removing a mask;
  • 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. 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 an effective alternative;
  • After using the toilet, put the toilet lid down before ¬flushing to avoid spreading germs;
  • When having respiratory symptoms, wear a surgical mask, refrain from work or attending class at school, avoid going to crowded places and seek medical advice promptly;
  • 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;
  • 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 - 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.

Remark: Face mask is not recommended for children under the age of 2 years without supervision.

Travel advice

Members of the public are strongly urged to avoid non-essential travel outside Hong Kong. If it is unavoidable to travel to countries/areas outside Hong Kong, they should take heed of the health advice below:

  • Complete COVID-19 vaccination before travel according to the latest recommendations to effectively protect against COVID-19 disease (For details on COVID-19 vaccination, please refer to thematic website for COVID-19 Vaccination Programme: www.covidvaccine.gov.hk);
  • Avoid visiting crowded places and maintain appropriate social distance with other people as far as possible;
  • Wear a surgical mask and maintain at all times strict personal and hand hygiene;
  • Perform hand hygiene frequently, 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; 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 an effective alternative;
  • Adhere to food safety and hygiene rules such as avoiding consuming raw or undercooked animal products, including milk, eggs and meat, or foods which may be contaminated by animal secretions, excretions (such as urine) or contaminated products, unless they have been properly cooked, washed or peeled;
  • If feeling unwell when outside Hong Kong, especially if experiencing respiratory symptoms, wear a surgical mask and seek medical advice at once; and
  • After returning to Hong Kong, consult a doctor promptly if experiencing any symptoms, take the initiative to inform the doctor of any recent travel history, and wear a well-fitted surgical mask to help prevent spread of the disease.

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