The SARS-CoV-2 coronavirus causes the disease called COVID-19, also known as the coronavirus 2019 disease.1

The following risk factors place a person at higher risk of getting COVID-192:

• older age
• being male
• diabetes
• high blood pressure
• heart disease
• cancer
• being in crowded places
• low education
• certain occupations (e.g. healthcare workers, taxi and bus drivers)
• being in an area with poor ventilation
• poor hygiene

COVID-19 spreads when a person breathes in particles in the air exhaled by infected individuals, which contain the virus, allowing for spread of the virus.3 Individuals who do not show symptoms and appear infected can still spread the virus, but this is much rarer.3-4 The SARS-CoV-2 virus, once inside the body, binds to receptors on the surface of cells in the nose, allowing it to enter the cell.1 Once inside, the virus hijacks the cells' systems to produce many copies of itself, with subsequent viral progeny being released from the cell via vesicle-mediated exocytosis and go on to infect more cells.5-6 As the disease progresses, the virus moves from the nose, to the throat, causing symptoms such as fever and dry cough as the immune system mounts an immune response.[6] In about one-fifth of patients, the virus moves all the way to the lungs and replicates there.6 In about one-fifth of patients, the virus migrates all the way to the alveolar cells of the lungs and replicates there.6 The immune system mounts a much stronger immune response, which goes out of control in a phenomenon known as a "cytokine storm".6 The subsequent inflammation causes lung damage and results in acute respiratory distress syndrome (ARDS).6

COVID-19 presents with the following symptoms7:

• fever
• cough
• tiredness
• loss of taste or smell
• sore throat
• headache
• aches and pains
• diarrhoea
• skin rash
• red or irritated eyes

• difficulty breathing
• Loss of speech/mobility
• confusion
• chest pain

See a doctor immediately if you have serious symptoms.

Taking a vaccine affords immunity against COVID-19 and its variants; you're much less likely to come down with COVID-19, less likely to get a severe case of COVID-19 if you do contract COVID-19, and less likely to die of COVID-19.8-9 Vaccines come with side effects following administration, such as fever, muscle aches and headaches, but they subside after a short period of time, and are very safe in general.8-10

Wearing a mask helps to protect others around you from getting COVID-19, should you be infected (whether you have symptoms or not).11-12 It blocks the infected droplets and particles that you breathe out from your nose and mouth from moving into the environment, hence reducing the spread of COVID-19.12

Practising social distancing helps to minimise close contact between persons, hence helping to reduce the spread of COVID-19.13-14

Practising good hygiene helps to clean surfaces that could potentially have infected droplets or particles on them, and is effective in reducing the spread of COVID-19.15 This involves hand washing, as well as cleaning of surfaces with soap or detergent.

Treatments exist for COVID-19:

• Nirmatrelvir/ritonavir (Paxlovid) helps to reduce the risk of serious illness or hospitalisation when taken by infected individuals.16
• Remdesivir (Veklury) helps to reduce hospitalisation stay when taken by infected individuals.17
• Bebtelovimab has a comparable reduction in risk of serious illness to Paxlovid.18
• Molnupiravir has been shown to be effective in reducing hospitalisation and risk of death in unvaccinated adults.19

The first few cases of COVID-19 appeared in Wuhan, China, with the patients having visited a wet seafood market.1 Subsequent spread of COVID-19 to almost all continents led to the World Health Organisation declaring a Public Health Emergency of International Concern (PHEIC) on January 30, 2020.20 COVID-19 was subsequently declared a pandemic on March 11, 2020 by the World Health Organisation.21 The first COVID-19 vaccine, Comirnaty (also known as the Pfizer-BioNTech COVID-19 Vaccine) was approved by the United States Food and Drug Administration on August 23, 2021.22 As of September 2022, COVID-19 has had 610,000,000 cumulative cases and 6.5 million deaths worldwide.23

Many countries took common measures against the COVID-19 pandemic, including social distancing, hygiene measures, mobility restrictions, and contact tracing.24 These measures had significant extraneous impact. Social distancing and mobility restrictions have resulted in a large decrease in global travel and tourism, with international arrival numbers around half of pre-pandemic levels.25 Additionally, such measures resulted in a “stay-at-home” recommendation or legislation during the initial part of the pandemic, resulting in adoption of “work-from-home”, as well as significant detrimental impacts on people's mental health during the pandemic.26-27

• The SARS-CoV-2 virus causes the COVID-19 disease
• The virus spreads through infectious droplets breathed out by infected persons.
• Symptoms include fever, cough, tiredness, loss of taste and smell, and a sore throat, among others
• You should get vaccinated, wear a mask, practise social distancing and good hygiene, so as to help prevent the spread of the virus.
• Check with your local healthcare provider on how to get vaccines.
• For instructions on how to wear a mask properly, see here.
• Practise social distancing by staying 1 metre apart from others, staying at home if possible and avoiding crowded areas.
• Practise good hygiene by washing your hands after touching a dirty surface and not touching your face with your hands.

• World Health Organisation
• United States Food and Drug Administration
• European Centre for Disease Prevention and Control
• Government of the United Kingdom
• Ministry of Health Singapore
• Australian Government Department of Health and Aged Care
• New Zealand Government
• Search about COVID-19 on PubMed

1. Sun J, He WT, Wang L, et al. COVID-19: Epidemiology, evolution, and cross-disciplinary perspectives. Trends Mol Med. 2020;26(5):483-495. doi: https://doi.org/10.1016/j.molmed.2020.02.008
2. Rashedi J, Mahdavi Poor B, Asgharzadeh V, et al. Risk factors for COVID-19. Infez Med. 2020;28(4):469-474.
3. Lotfi M, Hamblin MR, Rezaei N. COVID-19: Transmission, prevention, and potential therapeutic opportunities. Clin Chim Acta. 2020;508:254-266. doi:https://doi.org/10.1016/j.cca.2020.05.044
4. Byambasuren O, Cardona M, Bell K, Clark J, McLaws ML, Glasziou P. Estimating the extent of asymptomatic COVID-19 and its potential for community transmission: Systematic review and meta-analysis. Can J Infect Dis Med Microbiol. 2020;5(4):223-234. doi:https://doi.org/10.3138/jammi-2020-0030
5. Trougakos IP, Stamatelopoulos K, Terpos E, et al. Insights to SARS-CoV-2 life cycle, pathophysiology, and rationalized treatments that target COVID-19 clinical complications. J Biomed Sci. 2021;28(1):9. doi:https://doi.org/10.1186/s12929-020-00703-5
6. Parasher A. COVID-19: Current understanding of its pathophysiology, clinical presentation and treatment. Postgrad Med J. 2021;97(1147):312-320. doi:https://doi.org/10.1136/postgradmedj-2020-138577
7. Coronavirus disease (COVID-19). World Health Organisation. Accessed September 24, 2022. https://www.who.int/health-topics/coronavirus#tab=tab_3
8. Polack FP, Thomas SJ, Kitchin N, et al. Safety and efficacy of the BNT162b2 mRNA Covid-19 vaccine. N Engl J Med. 2020;383(27):2603-2615. doi:https://doi.org/10.1056/NEJMoa2034577
9. COVID-19 vaccines Work. Centres for Disease Control and Prevention. Updated June 28, 2022. Accessed September 24, 2022. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/effectiveness/work.html
10. Ganesan S, al Ketbi LMB, al Kaabi N, et al. Vaccine side effects following COVID-19 vaccination among the residents of the UAE—An observational study. Front Public Health. 2022;10. doi:https://doi.org/10.3389/fpubh.2022.876336
11. Leech G, Rogers-Smith C, Monrad JT, et al. Mask wearing in community settings reduces SARS-CoV-2 transmission. Proceedings of the National Academy of Sciences. 2022;119(23). doi:https://doi.org/10.1073/pnas.2119266119
12. Li H, Yuan K, Sun YK, et al. Efficacy and practice of facemask use in general population: a systematic review and meta-analysis. Transl Psychiatry. 2022;12(1):49. doi:https://doi.org/10.1038/s41398-022-01814-3
13. Sun C, Zhai Z. The efficacy of social distance and ventilation effectiveness in preventing COVID-19 transmission. Sustain Cities Soc. 2020;62:102390. doi:https://doi.org/10.1016/j.scs.2020.102390
14. Moosa IA. The effectiveness of social distancing in containing Covid-19. Appl Econ. 2020;52(58):6292-6305. doi:https://doi.org/10.1080/00036846.2020.1789061
15. Odusanya O, Odugbemi B, Odugbemi T, Ajisegiri W. COVID-19: A review of the effectiveness of non-pharmacological interventions. Niger Postgrad Med J. 2020;27(4):261. doi:https://doi.org/10.4103/npmj.npmj_208_20
16. Hammond J, Leister-Tebbe H, Gardner A, et al. Oral Nirmatrelvir for high-risk, nonhospitalized adults with Covid-19. N Engl J Med. 2022;386(15):1397-1408. doi:https://doi.org/10.1056/NEJMoa2118542
17. Beigel JH, Tomashek KM, Dodd LE, et al. Remdesivir for the treatment of Covid-19 — Final report. N Engl J Med. 2020;383(19):1813-1826. doi:https://doi.org/10.1056/NEJMoa2007764
18. Razonable RR, O'Horo JC, Hanson SN, et al. Comparable outcomes for bebtelovimab and ritonavir-boosted nirmatrelvir treatment in high-risk patients With coronavirus disease-2019 during severe acute respiratory syndrome coronavirus 2 BA.2 omicron epoch. J Infect Dis. Published online September 17, 2022. doi:https://doi.org/10.1093/infdis/jiac346
19. Jayk Bernal A, Gomes da Silva MM, Musungaie DB, et al. Molnupiravir for oral treatment of Covid-19 in nonhospitalized patients. N Engl J Med. 2022;386(6):509-520. doi:https://doi.org/10.1056/NEJMoa2116044
20. Yesudhas D, Srivastava A, Gromiha MM. COVID-19 outbreak: history, mechanism, transmission, structural studies and therapeutics. Infection. 2021;49(2):199-213. doi:https://doi.org/10.1007/s15010-020-01516-2
21. WHO Director-General's opening remarks at the media briefing on COVID-19 - 11 March 2020. World Health Organisation. Published March 11, 2020. Accessed September 24, 2022. https://www.who.int/director-general/speeches/detail/who-director-general-s-opening-remarks-at-the-media-briefing-on-covid-19---11-march-2020
22. FDA approves first COVID-19 vaccine. United States Food and Drug Administration. Published August 23, 2021. Accessed September 24, 2022. https://www.fda.gov/news-events/press-announcements/fda-approves-first-covid-19-vaccine
23. WHO coronavirus (COVID-19) dashboard. World Health Organisation. Updated September 23, 2022. Accessed September 24, 2022. https://covid19.who.int/
24. Bruinen de Bruin Y, Lequarre AS, McCourt J, et al. Initial impacts of global risk mitigation measures taken during the combatting of the COVID-19 pandemic. Saf Sci. 2020;128:104773. doi:https://doi.org/10.1016/j.ssci.2020.104773
25. Impact assessment of the COVID-19 outbreak on international tourism. United Nations World Tourism Organisation. Accessed September 24, 2022. https://www.unwto.org/impact-assessment-of-the-covid-19-outbreak-on-international-tourism
26. Galanti T, Guidetti G, Mazzei E, Zappalà S, Toscano F. Work From Home During the COVID-19 Outbreak. J Occup Environ Med. 2021;63(7):426-432. doi:https://doi.org/10.1097/JOM.0000000000002236
27. Matias T, Dominski FH, Marks DF. Human needs in COVID-19 isolation. J Health Psychol. 2020;25(7):871-882. doi:https://doi.org/10.1177/1359105320925149