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What is COVID-19?

COVID-19, or coronavirus disease 2019, is an infection caused by a specific virus type of novel coronavirus, the SARS-CoV-2. The virus first appeared in late 2019 in the city of Wuhan, China. But it has spread quickly since then, and there are now cases in all continents.

Did you know?

In February 2020, the World Health Organization (WHO) named the disease COVID-19., and the virus that causes COVID-19 is called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).1

Coronaviruses are a family of viruses that can cause respiratory illnesses with symptoms ranging from those similar to a common cold to pneumonia and severe acute respiratory syndrome (SARS).

At the end of 2019, a new, novel coronavirus was identified as the cause of several cases of pneumonia in Wuhan, a city in the Hubei Province of China. 

It rapidly spread, resulting in an epidemic throughout China, followed by an increasing number of cases in other countries throughout the world. 

The World Health Organization declared a global pandemic in March 2020.2

As of March 22nd, 2020, more than 290,000 people in 184 countries have been infected, with 13,000 deaths. Live information can be obtained from WHO's website.3

The Facts:


  • Investigation in Wuhan at the beginning of the outbreak identified an initial association with a seafood market that sold live animals, where most patients had worked or visited and which was subsequently closed for disinfection.
  • However, as the outbreak progressed, person-to-person spread became the main mode of transfer, mainly via respiratory droplets, resembling the spread of influenza.4
  • With droplet transfer, the virus is released in the respiratory secretions when a person with an infection coughs, sneezes, or talks and can infect another person if the droplets makes direct contact with the mucous membranes. The spread of infection can also occur if a person touches an infected surface and then touches his or her eyes, nose, or mouth. 


  • For COVID-19, the period between exposure to the virus and the appearance of the first symptoms is thought to take 2 to 14 days, with most cases showing signs approximately four to five days after exposure.5-7
  • The symptoms from the viral infection range from mild to critical; and most infections (around 4 out of 5) are not severe.8-10
  • In a research study describing 138 patients with COVID-19 pneumonia in Wuhan, the most common clinical symptoms at the start of illness were:11
    • Fever – may vary for some individuals
    • Fatigue (feeling tired) in 70 percent
    • Dry cough in 59 percent
    • Anorexia (losing weight) in 40 percent
    • Myalgias (muscle aches) in 35 percent
    • Dyspnea (shortness of breath) in 31 percent
    • Sputum (coughed up mucus) production in 27 percent
  • Another symptom gaining more attention is anosmia or lack of smell. 12
  • Other less common symptoms have included headache, sore throat, and rhinorrhea (“runny nose”). In addition to respiratory symptoms, gastrointestinal symptoms (eg, nausea and diarrhea) have also been reported in some patients, but these are relatively uncommon.
  • Pneumonia appears to be the most frequent serious manifestation of infection, characterized primarily by fever, cough, dyspnea (shortness of breath), and bilateral infiltrates (both lungs showing opacity or haziness) on chest imaging.9,11

Risk factors

  • Risk factors for COVID-19 appear to include:
    • Recent travel from or residence in an area with ongoing community spread of COVID-19 as determined by the World Health Organization.
    • Close contact with someone who has COVID-19 — such as when a family member or health care worker takes care of an infected person.
  • Patients with underlying medical conditions, such as cardiovascular disease, diabetes mellitus, chronic lung disease, hypertension, and cancer, are at increased risk of having COVID-19 and dying from it.13,14
  • Increasing age also appears to be related to more severe forms of infection. Death rates were 5.8% in Italy (median age of patients was 64 years) and 0.9% in South Korea (median age was in the 40s).15

What can we do about it?

Maintain a healthy lifestyle to boost your immune system.

Although there is no vaccine available to prevent infection with the novel coronavirus, you can take steps to reduce your risk of infection. Similar to the New Zealand Ministry of Health16, the Australian Government Department of Health17 recommends following these precautions for avoiding COVID-19.

  • Avoid large events and mass gatherings.
  • Avoid close contact with anyone who is sick or has symptoms.
    Keep distance between yourself and others if COVID-19 is spreading in your community, especially if you have a higher risk of having a serious illness.
  • Wash your hands often with soap and water for at least 20 seconds, or use an alcohol-based hand sanitiser that contains at least 60% alcohol.
  • Cover your mouth and nose with your elbow or a tissue when you cough or sneeze. Throw away the used tissue.
  • Avoid touching your eyes, nose and mouth if your hands aren't clean.
  • Avoid sharing dishes, glasses, bedding and other household items if you're sick.
  • Clean and disinfect surfaces you often touch on a daily basis.
  • Stay home from work, school and public areas if you're sick, unless you're going to get medical care. Avoid taking public transportation if you're sick.

Should I see a doctor or a nurse?17

  • If you have a fever, cough, or trouble breathing and might have been exposed to COVID-19, you should arrange to see your doctor for urgent assessment. Please call the surgery/clinic first before coming in. 
  • You might have been exposed if any of the following happened within the last 14 days:
  • You had close contact with a person who has the virus – This generally means being within about 2 metres of the person.
  • You lived in, or traveled to, an area where lots of people have the virus, such as China, Italy, Iran, Korea.
  • You went to an event or location where there were known cases of COVID-19 – For example, if multiple people was sick after a specific gathering or in your workplace, you might have been exposed.
  • You should telephone the doctor surgery/clinic or hospital before you arrive and tell them your travel history or that you may have been in contact with a potential case of COVID-19. You must remain isolated either in your home, hotel or a health care setting until public health authorities inform you it is safe for you to return to your usual activities.
  • If you are severely ill and need to go to the clinic or hospital right away, you should still call ahead. This way the staff can care for you while taking steps to protect others.
  • Many doctors are doing video or phone consultations with their patients. Your doctor will do an examination and ask about your symptoms. If your doctor suspects you have COVID-19, they might take a sample of fluid from inside your nose, and possibly your mouth, and send it to a lab for testing. 
  • If you need to seek more information on COVID-19, call the National Coronavirus Helpline in Australia, 24 hours a day, seven days a week. 1-800-020-080; or In New Zealand: 0800 358 5453 


COVID-19 is different from a regular flu. Although the majority of people who contract it will experience mild to moderate respiratory symptoms, it appears to spread more rapidly, causes more severe respiratory disease and carries a higher death rate. Preventive measures, such as good hygiene, social distancing and social isolation are key to stop the spread of the disease.



1.        World Health Organization. Director-General’s remarks at the media briefing on 2019-nCoV on 11 February 2020.

2.        World Health Organization. WHO Director-General’s Opening Remarks at the Media Briefing on COVID-19 - 11 March 2020.; 2020.

3.        World Health Organisation. Coronavirus disease (COVID-19) Pandemic. https://www.who.int/emergencies/diseases/novel-coronavirus-2019. Accessed May 3, 2020.

4.        World Health Organization. Novel Coronavirus Situation Report-2. January 22, 2020.; 2020.

5.        Li Q, Guan X, Wu P, et al. Early Transmission Dynamics in Wuhan, China, of Novel Coronavirus–Infected Pneumonia. N Engl J Med. 2020. doi:10.1056/nejmoa2001316

6.        Guan W-J, Ni Z-Y, Hu Y, et al. Clinical Characteristics of Coronavirus Disease 2019 in China. N Engl J Med. 2020. doi:10.1056/NEJMoa2002032

7.        Chan JFW, Yuan S, Kok KH, et al. A familial cluster of pneumonia associated with the 2019 novel coronavirus indicating person-to-person transmission: a study of a family cluster. Lancet. 2020. doi:10.1016/S0140-6736(20)30154-9

8.        Bajema KL, Oster AM, McGovern OL, et al. Persons Evaluated for 2019 Novel Coronavirus - United States, January 2020. MMWR Morb Mortal Wkly Rep. 2020. doi:10.15585/mmwr.mm6906e1

9.        Huang C, Wang Y, Li X, et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet. 2020. doi:10.1016/S0140-6736(20)30183-5

10.      Chen N, Zhou M, Dong X, et al. Epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in Wuhan, China: a descriptive study. Lancet. 2020. doi:10.1016/S0140-6736(20)30211-7

11.      Wang D, Hu B, Hu C, et al. Clinical Characteristics of 138 Hospitalized Patients with 2019 Novel Coronavirus-Infected Pneumonia in Wuhan, China. JAMA - J Am Med Assoc. 2020. doi:10.1001/jama.2020.1585

12.      Xydakis MS, Dehgani-Mobaraki P, Holbrook EH, et al. Smell and taste dysfunction in patients with COVID-19. Lancet Infect Dis. April 2020. doi:10.1016/s1473-3099(20)30293-0

13.      Wu Z, McGoogan JM. Characteristics of and Important Lessons From the Coronavirus Disease 2019 (COVID-19) Outbreak in China. JAMA. 2020. doi:10.1001/jama.2020.2648

14.      Zhou F, Yu T, Du R, et al. Articles Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan , China : a retrospective cohort study. Lancet. 2020. doi:10.1016/S0140-6736(20)30566-3

15.      Korea Centre for Disease Control and Prevention. Updates on COVID-19 in Korea. March 14, 2020.; 2020.

16.      Health NZM of. COVID-19 (novel coronavirus) – health advice for the general public | Ministry of Health NZ. Ministry of Health, Manatu Hauora. https://www.health.govt.nz/our-work/diseases-and-conditions/covid-19-novel-coronavirus/covid-19-novel-coronavirus-health-advice-general-public. Published 2020. Accessed March 17, 2020.

17.      Australian Government Department of Health. Coronavirus Disease (COVID-19): What You Need to Know. Version 15 (17/03/2020).; 2020.

Dr. Luiz Fernando SellaMD, MPH
Medical Doctor at the Federal University of Santa Catarina, Brazil, a Certified Lifestyle Medicine Physician and Health and Wellness Coach.