Most cases of COVID-19 are mild, but mild does not mean symptom-free. Most people with COVID-19 develop a fever and a cough, but the other symptoms vary depending on the severity of the illness.

People with any symptoms of COVID-19 or another illness should stay home until they are symptom-free. People who are not displaying any symptoms but have been in contact with someone who does have symptoms should also stay home.

People who have mild symptoms or are asymptomatic can still pass the virus on. While COVID-19 may only cause a mild cough in some people, it can lead to life threatening complications in others, especially older adults or those with underlying health conditions.

Recent research in Wuhan, China, suggested that most people develop symptoms within 4 days of exposure, but the virus may remain dormant for up to 2 weeks. More recently, a study confirmed that the median incubation period for the virus is about 5 days.

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Keep reading to learn more about the symptoms of COVID-19 by severity level.

Some people who have COVID-19 are asymptomatic. This means that they do not have any known symptoms of COVID-19 or associated symptoms, such as sneezing.

A person who is asymptomatic might pass on the virus to others without even realizing it.

Anyone who has tested positive but is asymptomatic should continue social distancing. They should wear a cloth face mask in public spaces where it is difficult to adhere to social distancing rules.

Anyone who has had contact with someone who has tested positive, whether showing symptoms or not, should also follow these rules. They may also have COVID-19 without realizing it.

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People with COVID-19 may experience a fever.

The difference between mild and moderate symptoms is a matter of degree, and the treatment is more or less the same.

The most common symptoms of mild-to-moderate cases are:

  • A fever: The majority of people with COVID-19 experience a fever. A study in The Lancet in January 2020 noted that 98% of people with a COVID-19 diagnosis had a fever. In mild-to-moderate cases, people will typically experience a fever up to 103℉ (39.4℃).
  • Fatigue: Some people might have less energy or need more sleep.
  • A cough: The cough tends to be dry, but it may not always be.

Other less common symptoms include:

  • sore throat
  • headache
  • nasal congestion
  • malaise
  • muscle aches
  • gastrointestinal issues, such as diarrhea, nausea, or vomiting
  • lack of appetite

Most research on COVID-19 has focused on people who have sought treatment for the disease. The existing data, therefore, have a bias toward people with more severe symptoms.

While viruses such as the flu often hit babies and young children very hard, most research around COVID-19 suggests that young people are likely to experience mild symptoms or no symptoms at all.

While early reports on COVID-19 focused primarily on respiratory symptoms, new research featuring in the American Journal of Gastroenterology indicates that 50.5% of people with COVID-19 experience gastrointestinal symptoms, such as diarrhea.

According to ENT UK, some people also report changes in their sense of smell or taste, often before other symptoms appear. Doctors do not understand what causes this, but other viruses can also attack the sense of smell, sometimes permanently.


People with mild-to-moderate symptoms of COVID-19 should do the following:

  • Stay home and away from others as much as possible.
  • Wear a cloth mask.
  • Monitor symptoms.
  • Contact a doctor or healthcare provider by phone or the internet to determine whether symptoms require medical attention.
  • Self-treat by following a healthcare professional’s recommendations.
  • Seek emergency medical treatment if symptoms develop to become severe.

Data on the prevalence of severe symptoms are hard to interpret because testing in the United States remains limited. Most people only seek medical care if they have severe symptoms, and some may not notice any symptoms at all.

Symptoms of severe cases typically include:

  • high fever above 103℉ (39.4℃)
  • difficulty breathing
  • blue lips or face
  • persistent pain or pressure in the chest
  • new-onset confusion (“altered mental status”)
  • trouble waking up, even when another person tries to wake them

On average, people who develop severe symptoms, such as shortness of breath, do so within 8 days of other symptoms first appearing.

People with preexisting medical conditions may notice that their symptoms get worse.

A viewpoint article in JAMA in March 2020 indicated that 12% of all people with a COVID-19 diagnosis in Italy needed treatment in intensive care units. These figures are, of course, constantly changing.

Figures from China in February indicated that 5% of more than 72,000 people with COVID-19 had received a classification of being in a “critical condition.”

However, it is difficult to assess the accuracy of these figures since many people with COVID-19 may not seek care, and some have no symptoms at all.

It is also important to note that these numbers continue to change as the coronavirus outbreak spreads.

In addition to the severe symptoms described above, people who develop severe life threatening COVID-19 symptoms are likely to experience:

  • weak pulse
  • cold hands or feet
  • requiring medical treatment to maintain organ function and life

Critical cases of COVID-19 may also lead to:

  • Sepsis: Sepsis is a type of systemic infection that occurs when the body’s immune response overreacts to pathogens, causing potentially life threatening damage.
  • Respiratory failure: This condition occurs when damage to the lungs is so severe that they cannot function without assistance.
  • Organ failure: This life threatening situation occurs when one or more organs stop working properly.

In China, 49% of critical cases have led to death, as a February article in JAMA reported.

Certain medical conditions increase the risk of death or developing critical symptoms of COVID-19. These include:

  • heart disease
  • diabetes
  • chronic respiratory disease, such as chronic obstructive pulmonary disease (COPD)
  • high blood pressure (hypertension)
  • cancer

According to a viewpoint article in JAMA, figures recorded at the end of February in China indicated that symptoms tend to be more severe in older populations. The Chinese fatality rate in people over 70 years of age was 8%, while the death for those over 80 years of age was 14.8%.

Extended exposure to the virus may also increase the severity of symptoms. In China, several otherwise healthy healthcare workers died. Overall, 14.8% of healthcare workers who contracted SARS-CoV-2 received a classification of severe or critical.

SARS-CoV-2 is a new virus, and doctors still do not fully understand how it spreads, how well it survives on surfaces, and how it affects people.

Cases of COVID-19 range from asymptomatic to critical, and, in some instances, they can lead to organ failure and death.

Without more data, the safest strategy is to assume that COVID-19 is potentially deadly and spreads easily and that people without symptoms can transmit it.

To slow the spread and reduce the death rate, people should minimize social contact, stay at home as much as possible, and wash their hands frequently.

For live updates on the latest developments regarding the novel coronavirus and COVID-19, click here.