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JAMA Patient Page
July 10, 2020

What Is COVID-19?

Author Affiliations
  • 1Division of Infectious Diseases, Department of Medicine, Amsterdam UMC, Location UMC, University of Amsterdam, Amsterdam, the Netherlands
  • 2Division of Pulmonary and Critical Care Medicine, University of Michigan, Ann Arbor
JAMA. 2020;324(8):816. doi:10.1001/jama.2020.12984

Coronavirus disease 2019 (COVID-19) is a disease caused by a new coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Coronaviruses are a cause of the common cold, but SARS-CoV-2, which likely came from bats, causes more severe disease in many patients.1

Symptoms and Diagnosis

Symptoms occur on average about 5 days after exposure to the virus. Almost all patients develop symptoms within 12 days. Therefore, a 14-day self-isolation is recommended for people who were likely exposed to the virus. The most common symptoms are cough, fever, and shortness of breath; most patients with COVID-19 have at least 1 of these. Other common symptoms include muscle aches, fatigue, nausea, vomiting, and diarrhea. People may also have loss or change in sense of taste and smell.2

COVID-19 is typically diagnosed by a swab of the nose that measures the coronavirus. There are also blood tests that can measure recent exposure to the virus, but these do not show positive results until 1 to 3 weeks after infection starts.

COVID-19 Disease Progression and Treatment

The virus typically enters through the eyes, mouth, or nose then travels down the throat, where it may cause a cough. In some patients, the virus enters the lungs and may cause pneumonia. Pneumonia leads to fluid filling the air sacs in the lungs, which makes breathing difficult. Most patients with pneumonia must be hospitalized and treated with oxygen. Some patients become very ill and need life support such as mechanical ventilation. About 1 in 20 patients with COVID-19 dies. However, death rates vary substantially by age, ranging from 1 in 900 patients aged 18 to 29 years to 1 in 34 aged 50 to 64 years and 1 in 3 aged 85 years or older.

There is currently no vaccine to reduce risk of COVID-19. Several potential vaccines are in development, which may help prevent COVID-19 in the future. For most patients, treatment is supportive. Antibiotics do not work for this viral disease. Studies are testing many antiviral medications, as well as medications to modify the body’s response to the virus. For certain hospitalized patients, antiviral drugs and steroids may help.

Patients with COVID-19 are likely to have fatigue and decreased energy for 6 to 8 weeks. It may be difficult to resume the same activity and exercise as before COVID-19, but it is important to remain active and increase exercise gradually. For most patients, lung function returns to normal after pneumonia.

Scientists do not know if people can have COVID-19 more than once, but repeat infection may be possible, particularly for people with mild symptoms during their initial infection.

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Article Information

Published Online: July 10, 2020. doi:10.1001/jama.2020.12984

Conflict of Interest Disclosures: Dr Wiersinga reported receiving grants from the Netherlands Organisation of Scientific Research. Dr Prescott reported receiving grants from the National Institutes of Health, Agency for Healthcare Research and Quality, and Department of Veterans Affairs and serving on the Surviving Sepsis Campaign.

Wiersinga  WJ, Rhodes  A, Cheng  AC,  et al.  Pathophysiology, transmission, diagnosis, and treatment of coronavirus disease 2019 (COVID-19): a review.   JAMA. Published online July 10, 2020. doi:10.1001/jama.2020.12839Google Scholar
Huynh  PP, Ishii  LE, Ishii  M.  What is anosmia?   JAMA. Published online June 18, 2020. doi:10.1001/jama.2020.10966PubMedGoogle Scholar
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    2 Comments for this article
    Risk of Death Following Covid-19 Infection
    David Bennett, MSc | Pharmaceutical Consultant
    For patient communication it would be safer to stress that the risk of death quoted in this paper refers to hospital patients. There is a danger that a member of the public infected with Covid-19 but not requiring hospitalisation would consider themselves a patient and so think that their risk of death is 1 in 900 (or other, according to their age).
    Lessons from COVID-19
    Michael McAleer, PhD (Econometrics), Queen's | Asia University, Taiwan
    The helpful, instructive and cautionary explanations on coronaviruses and pneumonia by experts in infectious diseases and critical care medicine are an important and commendable public service in this JAMA Patient Page.

    Clear and verifiable pronouncements of the symptoms, diagnosis, progression and treatment of the effects of the SARS-CoV-2 virus that leads to the COVID-19 disease after exposure are salutary lessons on the virulent nature of the virus and disease.

    The discussion gives a warning to individuals of the need to be cautious, extremely so for those with existing comorbidities and weakened immune systems.

    Alternative tests through swabbing
    and blood samples are explained in terms of the time taken to obtain positive outcomes, but there is no discussion of their accuracy and success in detecting true positive and true negative outcomes.

    Instances of repeat infections are not given extensive coverage, possibly because of a current lack of clinical trials.

    Alternative treatment options are presented, with an explanation that the lack of a vaccine cannot be replaced by antiviral medications and steroids.

    The comment: "For most patients, lung function returns to normal after pneumonia", might be regarded as premature in light of recent findings that COVID-19 deaths have been recorded as leading to blood clots in multiple organs, not just the lungs.

    Clinical trials of the long term effects on patients who have purportedly recovered from COVID-19 are not yet available.