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COVID-19 (coronavirus disease 2019), formerly known as 2019-nCoV

Written by Ada’s Medical Knowledge Team

Updated on

This is based on the evolving but still limited knowledge of the new coronavirus. It will be updated as new scientifically credible information becomes available.

COVID-19 (coronavirus disease 2019)

COVID-19 is the disease resulting from infection by a new respiratory virus (SARS-CoV-2), first identified on December 8, 2019 in Wuhan, Hubei Province, China as the cause of a respiratory illness outbreak. The name ‘COVID-19’ was suggested by the WHO (World Health Organization), using established guidelines.[1]

Reported affected areas

In the beginning, most cases were detected in China. Europe and North America are now epicentres of the outbreak, however, all continents are reporting an increasing number of cases. The COVID-19 outbreak was declared a pandemic by the WHO on March 11, 2020.[2]

Causes and risks

Coronaviruses are a large family of viruses that cause infection in a variety of animal species. Bats appear to be the reservoir of the COVID-19 virus, but the intermediate host(s) has not yet been identified.[3] Coronaviruses can also spread between animals and humans, and in some cases, also between humans. This is rare, but in the past, has led to outbreaks (MERS-CoV and SARS).

Initially, many of the patients in the COVID-19 outbreak were linked to a large market selling seafood and live animals – suggesting it was spread by animal-to-person contact. However, subsequent cases did not have direct exposure to animal markets, indicating person-to-person transmission.[4] This has been observed both within and outside of China.

The disease spreads from person to person through small droplets from the nose or mouth which are passed when a person with COVID-19 coughs or exhales. These droplets land on surrounding objects and surfaces. Other people then catch COVID-19 by touching these objects or surfaces, then touching their eyes, nose, or mouth. People can also catch COVID-19 if they inhale droplets from a person with COVID-19 who coughs or exhales droplets. Studies suggest that the virus is mainly transmitted through contact with respiratory droplets rather than through the air. While investigations suggest the virus may be found in feces in some cases, the risk of fecal-oral transmission seems to be low.[5]

Your risk level depends on where you live, your age, and your overall health. The majority of cases are adults, with 2 percent younger than 20 years old. Most patients (80 percent) experienced mild illness and recovered without needing special treatment. Around 14 percent experienced severe disease, and 5 percent were critically ill.[6] Approximately 2–3 percent of people with the disease have died.[5]

Signs and symptoms

Typical signs and symptoms include fever, dry cough, fatigue, coughing up phlegm, and shortness of breath. Some cases also report sore throat, headache, muscle pain, and chills.

More serious cases develop severe pneumonia, acute respiratory distress syndrome, sepsis, and septic shock that can lead to death. People over 60 and those with existing chronic conditions (namely hypertension, diabetes, cardiovascular disease, chronic respiratory disease, and cancer) seem to be more vulnerable to severe illness and death.[3][5]

Current estimates of the time between infection and onset of symptoms range from one to 14 days with average estimates of five to six days. While people are mostly infectious when they show symptoms, there are indications that rarely, some people might transmit the virus without showing any symptoms or before the symptoms appear. If this is confirmed, it would make early detection of COVID-19 infections more difficult. However, it is not unusual for viral infections of this type. For example, this is also seen with measles.[7]

If you are worried you may be infected, you can now use the Ada COVID-19 assessment and screener Please keep in mind that further testing will be necessary to diagnose COVID-19.

Diagnosis

Outside of mainland China, laboratory testing of respiratory samples confirm SARS-CoV-2 infection.[8]

Who should be tested for COVID-19?[7]

People who have a sudden onset of at least one of the following should be tested:

  • fever
  • cough
  • shortness of breath.

Current advice for testing depends on the stage of the outbreak in the country or area where you live. Areas have different outbreaks, even within the same country, and testing approaches will be adapted to the situation at a national and local level.[7]

People who, in the 14 days before the onset of symptoms, fulfilled at least one of the following criteria should also be tested:

  • close contact with a COVID-19 patient (living in the same household, healthcare-associated exposure, working together in close proximity or sharing the same classroom environment, or traveling together)
  • a history of traveling to areas with ongoing community transmission of COVID-19
  • worked in or attended a healthcare facility where patients with COVID-19 infections were being treated.

What should you do if you fit these criteria?

  • As the measures differ between countries, contact your local public health authority to get advice on what to do.
  • Before you go to a doctor’s office or the emergency room, call ahead and tell them about your recent travels and your symptoms, and then, follow their advice.
  • Avoid contact with others.
  • Do not travel while sick.
  • Cover your mouth and nose with a tissue or your sleeve (not your hands) when coughing or sneezing.
  • Wash your hands often with soap and water for at least 20 seconds. Use an alcohol-based hand sanitizer (containing at least 60 percent alcohol) if soap and water are not available.[9]

Treatment

To date, there is no specific medicine recommended to prevent or treat the novel coronavirus. However, those infected with COVID-19 should receive appropriate care to relieve and treat symptoms, and those with severe illness should receive optimal supportive care. Some specific treatments are under investigation and will be tested through clinical trials.[5]

Prevention

At present, there is no vaccine to prevent COVID-19. Avoiding exposure to the virus is the best way to prevent infection. Standard measures to prevent the spread of respiratory viruses apply, which include:

  • Wash your hands frequently with soap and water for at least 20 seconds. If soap and water are not available, use an alcohol-based hand sanitizer (containing at least 60 percent alcohol).
  • Avoid touching your eyes, nose, or mouth with unwashed hands.
  • Avoid close contact with anyone who has fever and cough, maintain at least a 1-metre distance (social distancing).
  • Stay home when you are sick.
  • Cover your cough or sneeze with a tissue, and then throw the tissue in the trash.
  • Clean and disinfect frequently touched objects and surfaces.[10]

For travelers going to affected areas:

Several countries[9][11][12] have restricted travel to affected areas (those which are experiencing ongoing transmission of COVID-19). In general, avoid non-essential travel, both to reduce individual risk, as well as to prevent quarantine measures upon return.

If travel cannot be avoided, or you are already in an affected area, please note the following:

  • Avoid contact with sick people.
  • Discuss travel to the affected area with your healthcare provider – older adults and people with underlying health issues may be at higher risk.
  • Avoid animals (alive or dead), animal markets, and animal products such as uncooked meat
  • Wash hands often with soap and water for at least 20 seconds. If soap and water are not available, use an alcohol-based hand sanitizer (containing at least 60 percent alcohol).[9]

For even more details, read our Ada Editorial article on the novel coronavirus where one of our doctors, Dr. Gilsdorf, answers your most commonly asked questions.


  1. World Health Organization. “WHO best practices for naming of new human infectious diseases”

  2. World Health Orginization. “WHO Director-General's opening remarks at the media briefing on COVID-19 - 11 March 2020”. 11 March 2020.

  3. World Health Orginization. “Report of the WHO-China Joint Mission on Coronavirus Disease 2019 (COVID-19)”. 24 February 2020.

  4. Centers for Disease Control and Prevention. “About Coronavirus Disease 2019 (COVID-19)”. 24 February 2020.

  5. World Health Orginization. “Q&A on coronaviruses (COVID-19)”. 9 March 2020.

  6. World Health Orginization. “Coronavirus disease 2019 (COVID-19). Situation Report – 41”. 1 March 2020.

  7. European Centre for Disease Prevention and Control. “Q & A on COVID-19”. 6 March 2020.

  8. Centers for Disease Control and Prevention. “Coronavirus Disease 2019 (COVID-19) Situation Summary”. 21 March 2020.

  9. Center for Disease Control. “Travel Notices: COVID-19 in China”. 17 March 2020.

  10. World Health Orginization. “Coronavirus disease (COVID-19) advice for the public”. 18 March 2020.

  11. Auswärtiges Amt. “China: Reise- und Sicherheitshinweise (Teilreisewarnung)”. 24 March 2020.

  12. GOV.UK. “Foreign travel advice: China”. 22 March 2020.

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