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What is COVID-19?
COVID-19 is a respiratory disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
In December 2019, a cluster of pneumonia cases was detected in Wuhan, China. The pathogen involved was identified as a novel coronavirus (SARS-CoV-2), and the disease was named COVID-19. The World Health Organization (WHO) declared the COVID-19 outbreak a Public Health Emergency of International Concern (PHEIC) from 30 January 2020 to 5 May 2023.
In Singapore, the first case of COVID-19 was confirmed on 23 January 2020. Like other countries, Singapore has experienced multiple waves of infection (i.e. Alpha, Delta, and Omicron) since the start of the pandemic.
How is COVID-19 transmitted?
COVID-19 spreads mainly through the respiratory droplets or tiny particles released when an infected person coughs, sneezes, talks, or sings. Other people can breathe in these droplets and particles, or these droplets and particles can land on others’ eyes, nose, or mouth.
The virus can also be spread indirectly when a person touches a contaminated surface (e.g. doorknob, utensils) then touches his or her eyes, nose, or mouth.
The incubation period for COVID-19 varies across variants from 0 to 14 days, with more recent variants such as Omicron having a shorter range from 0 to 8 days.
What are the symptoms of COVID-19?
The signs and symptoms of a COVID-19 infection range from mild respiratory symptoms to severe illnesses such as pneumonia.
Infection is mild in the majority of persons and up to 1 in 3 infected persons are asymptomatic.
Common symptoms of COVID-19 include:
Fever
Chills
Sore throat
Cough
Nasal congestion, runny nose
Headache
Loss of taste or smell
Fatigue
Muscle aches
Nausea
Diarrhoea
In severe cases, COVID-19 can manifest as pneumonia with shortness of breath and chest pain.
Some may experience long-term effects from COVID-19 infection known as “Long COVID” or Post-Acute Sequelae of COVID-19 (PASC). "Long COVID" or PASC is a general reference to new or persistent symptoms experienced by some persons 4 weeks or more after a COVID-19 infection with no alternate diagnosis.
Such persistent symptoms are more commonly seen after severe COVID-19 and among unvaccinated persons. Most symptoms, such as cough and fatigue, resolve on their own over time. However, persons with more severe symptoms, such as shortness of breath or chest pain, may require further medical assessment and care, and are advised to seek medical attention.
What are the risk factors?
Individuals at greater risk of severe disease or complications when infected include:
Seniors aged 60 years and above.
Pregnant women.
Persons who are immunocompromised or have concurrent medical conditions such as obesity, diabetes, heart, or lung disease.
How is COVID-19 treated?
COVID-19 is usually mild and self-limiting. Supportive care and symptom-relieving treatment, such as treatment with fever-reducing medications, staying well-hydrated, and getting enough rest, are usually enough to manage the acute symptoms of COVID-19.
Medical treatment of COVID-19 is mostly supportive although antiviral medication may be prescribed by doctors where appropriate, such as for cases with severe disease or at high risk of severe COVID-19.
How to prevent COVID-19?
COVID-19 vaccination protects against severe disease, such as hospitalisation and deaths. For more information on the national COVID-19 vaccine recommendations please refer to this page.
Other preventive measures include:
Always observing and practising good personal hygiene
Washing hands regularly with soap, especially before handling food or eating, after going to the toilet, or when hands are dirty from coughing or sneezing. If water is not available, use an alcohol-based hand sanitiser that contains at least 60% alcohol.
Covering your mouth with a tissue when coughing or sneezing, and dispose the soiled tissue into the bin immediately. Avoid touching your face, including eyes, nose and mouth with unwashed hands after coughing or sneezing.
Avoiding sharing of food or drinks, or eating utensils
Wearing a mask and seek medical attention promptly when unwell
Please refer to Health Advice for Travellers for the full list of precautions to take when travelling.