Understanding COVID-19

Understanding COVID-19

Coronaviruses (CoV) are a large family of viruses that cause illness ranging from the common cold to more severe diseases; as a group they are common across the world.  Coronaviruses are zoonotic – this means that they are transmitted between animals and people.

COVID-19 is the infectious disease caused by the most recently discovered novel coronavirus  SARS-CoV-2. This new virus and disease were unknown before the outbreak began in Wuhan, China, in December 2019.

Origin of SARS-CoV-2 (the virus causing COVID-19)

All available evidence for COVID-19 suggests that SARS-CoV-2  also has a zoonotic source. It is now believed that that transmission of the virus to humans happened through some animal species more likely to be handled by humans. This intermediate animal host or zoonotic source (a domestic animal, a wild animal, or a domesticated wild animal) has not been identified. For more information, click here.

About COVID-19

COVID-19 affects the respiratory system (lungs and breathing tubes). People confirmed to have COVID-19 may experience these symptoms:

  • A new continuous cough
  • A high temperature (above 38 degrees C)
  • A loss of, or change in, your normal sense of taste or smell (anosmia)
  • Shortness of breath
  • A sore throat

Infections with mild symptoms (such as cold-like symptoms) or no symptoms at all are likely, though to what extent they occur is not yet known.

How serious is a COVID-19 infection?

We think there are many people with mild or moderate symptoms, but some people can become seriously ill and require treatment in hospital. Those most at risk of becoming seriously unwell are those with weakened immune systems, older people and those with pre-existing health conditions such as diabetes, cancer and chronic lung disease.

How does COVID-19 spread?

Understanding of the virus and the disease it causes continues to evolve. COVID-19 can be spread through person-to-person contact. The virus is thought to spread through touching infected surfaces and from an infected person’s respiratory secretions, such as through coughing. Read more about routes of infection from COVID-19 here. However, the precise ways the virus spreads are not currently well understood.

Not everyone who has had close contact with someone confirmed as having COVID-19 has been infected or become ill (read more on close contacts here).

As lock-down measures are relaxed, it is particularly important to try to maintain physical distancing. 

WHO periodically updates the Global Surveillance for human infection with COVID-19. For information on case definitions, click here.

If you develop any COVID-19 suspected symptoms, go home immediately and call 111 for advice.