COVID-19: Just the Facts

Topic Progress:

Pearls for COVID-19

1. Expect the practice on COVID-19’s origins to change.
2. It is not just the flu; it is highly contagious and we don’t fully understand the virus and its disease.
3. Patients crash quickly.


SARS-CoV2, otherwise known as COVID-19, initially emerged in Wuhan, China in late 2019. It is thought to have originated in bats and was transmitted to humans, most likely at the South China Wet Market, a market that deals in large amounts of live and freshly slaughtered animals. After initial containment failed, the virus spread quickly across the globe and was declared a pandemic by the World Health Organisation (WHO) on the 11th of March 20201.


SARS-COV2 is associated with several transmission modalities. The virus appears to be transmitted through small droplets expelled from the respiratory tract of an infected person (often whilst coughing or sneezing). Should these droplets then pass into the body of a second person (most often through the respiratory tract or the eyes), the second person may be infected2.

These droplets can be passed to a recipient by means of direct transmission (i.e. the infected person touches their mouth and then touches the recipient’s face, or coughs or sneezes onto the second person) and indirect transmission (the infected person touches a surface, depositing a droplet, and then the second person subsequently touches that surface)2.

Click here to read the isolation and PPE lesson.

From Infection to Symptoms to Illness

Patients are usually infected and do not show symptoms until ~11.5 days. Most will develop symptoms within 14 days as a whole3 though some people have been found to take up to 18 days to show symptoms4.

The time from symptom onset to dyspnea has been reported as 2-17 days (with patients requiring hospital admission often developing dyspnea later in their disease course), and time from symptom onset to respiratory failure is often >7 days4-5.

Common Symptoms

  • Fever
  • Cough
  • Headache
  • Confusion
  • Sore throat
  • Rhinorrhoea
  • Chest pain
  • General weakness
  • Shortness of breath
  • Nausea
  • Vomiting
  • Diarrhorea

Patients Crash Quickly

Patients will most often present complaining of shortness of breath and hypoxemia with less common presentations including diarrhea and hemoptysis. Clinicians should be vigilant for the phenomenon of ‘silent hypoxemia’ that is, a patient presenting with no appreciable respiratory distress but is revealed to be hypoxemic after the application of a SpO2 probe, silent hypoxemia seems to be more common in the elderly5-6.

More Info.

Osmosis has a comprehensive video summary of COVID-19.

Even More

Internet Book of Critical Care


  1. World Health Organisation (WHO)a. (2020). Coronavirus disease 2019 (COVID-19): Situation Report –51. Retrieved 28 March 2020, from
  2. Centre for Disease Control (CDC). (2020a). Coronavirus Disease 2019 (COVID-19): Interim infection prevention and control recommendations for patients with suspected or confirmed coronavirus disease 2019 (COVID-19) in healthcare settings. Retrieved 4 April 2020, from
  3. Lai, C., Shih, T., Ko, W., Tang, H., & Hsueh, P. (2020). Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and coronavirus disease-2019 (COVID-19): The epidemic and the challenges. International Journal Of Antimicrobial Agents, 55(3), 105924. doi: 10.1016/j.ijantimicag.2020.105924
  4. Li, Q., Guan, X., Wu, P., Wang, X., Zhou, L., Tong, Y., Ren, R., Leung, K., Lau, E., Wong, J., Xing, X., Xiang, N., Wu, Y., Li, C., Chen, Q., Li, D., Liu, T., Zhao, J., Liu, M., Tu, W., Chen, C., Jin, L., Yang, R., Wang, Q., Zhou, S., Wang, R., Liu, H., Luo, Y., Liu, Y., Shao, G., Li, H., Tao, Z., Yang, Y., Deng, Z., Liu, B., Ma, Z., Zhang, Y., Shi, G., Lam, T., Wu, J., Gao, G., Cowling, B., Yang, B., Leung, G. and Feng, Z., 2020. Early Transmission Dynamics in Wuhan, China, of Novel Coronavirus–Infected Pneumonia. New England Journal of Medicine, 382(13), pp.1199-1207.
  5. Guan, W., Ni, Z., Hu, Y., Liang, W., Ou, C., & He, J. et al. (2020). Clinical Characteristics of Coronavirus Disease 2019 in China. New England Journal Of Medicine. doi: 10.1056/nejmoa2002032
  6. Xie, J., Tong, Z., Guan, X., Du, B., Qiu, H., & Slutsky, A. (2020). Critical care crisis and some recommendations during the COVID-19 epidemic in China. Intensive Care Medicine. doi: 10.1007/s00134-020-05979-7

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