COVID-19 is a highly contagious infectious disease that the newly identified virus SARS-CoV-2 causes. SARS-CoV-2 belongs to the family of viruses known as coronaviruses.

In the majority of people who develop it, COVID-19 causes a mild respiratory illness similar to influenza. In some individuals, however, it can lead to a severe respiratory condition that requires hospitalization.

People can be without symptoms, or asymptomatic, despite having a SARS-CoV-2 infection. This means that they can still spread the virus to others even though they do not feel unwell. This makes COVID-19 potentially dangerous, as it is highly infectious.

At this time, there is no cure for COVID-19. However, people can protect themselves and help prevent the spread of this so-called novel coronavirus by:

  • frequently washing their hands
  • not touching their face
  • avoiding close contact with people who are sick

Keep reading to learn more about COVID-19, including the symptoms, likely incubation period, special considerations for high risk groups, and more.

a medical professional at a Drive Through COVID-19 Testing Facility Share on Pinterest
A person can still transmit SARS-CoV-2 even if they do not have symptoms.
Image credit: Joe Raedle / Getty Images

Coronaviruses are a large family of viruses that cause respiratory illnesses, ranging from the common cold and flu to more severe diseases, such as Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS).

The symptoms of COVID-19 are usually mild and tend to begin 2–14 days after exposure to the virus. Symptoms may vary from person to person.

The Centers for Disease Control and Prevention (CDC) report that COVID-19 may cause the following symptoms:

  • a cough
  • shortness of breath or difficulty breathing
  • a fever
  • chills
  • muscle pain
  • a sore throat
  • a new loss of taste or smell

The World Health Organization (WHO) state that less common symptoms include diarrhea, headache, a skin rash, and discoloration of the fingers or toes.

According to the WHO, about 80% of people recover from the illness without needing treatment in a hospital. However, they note that approximately 1 in every 5 people who get COVID-19 become seriously ill and may develop difficulty breathing.

Older people, as well as those with underlying medical concerns, such as chronic lung disease, heart problems, or diabetes, might be at higher risk of severe illness from COVID-19.

The following sections will discuss these groups and their risk of severe illness in more detail.

Older adults

Adults aged 65 years and older are at higher risk of severe illness from COVID-19. In fact, about 8 out of 10 deaths reported in the United States have been in this age group.

Individuals in this age group should discuss their risks with a doctor or let them know if they are experiencing any symptoms of COVID-19.

People with preexisting health conditions

Currently, there is little information about how COVID-19 affects people with certain preexisting health conditions. However, researchers have identified the following as conditions that may increase a person’s risk of serious illness due to COVID-19.

Chronic respiratory conditions

These include:

  • chronic obstructive pulmonary disease (COPD)
  • emphysema
  • asthma

Since COVID-19 is a respiratory disease, those with preexisting respiratory conditions may have a higher risk of developing a serious illness.

For example, because asthma can worsen due to other coronavirus strains, those with asthma should follow all protection and prevention precautions.

It is also important that individuals with asthma keep their symptoms under control by taking their prescribed medications.

Hypertension and cardiovascular conditions

Individuals with cardiovascular diseases, hypertension, or both may also be at greater risk of severe illness and death due to COVID-19.

Numerous studies from China have found that many people with COVID-19 in intensive care units (ICU) who also had either heart disease or hypertension have died.


Diabetes is another condition that may put a person at risk of serious illness due to COVID-19. Studies from China have reported that many patients admitted to the ICU with coronavirus had diabetes.


People undergoing cancer treatment, such as chemotherapy, may also be at greater risk of serious illness due to COVID-19. This risk is because their immune systems may be weaker as a result of their cancer treatment. However, there is only limited evidence for this.

Sickle cell disease

Individuals with sickle cell may be more at risk of showing more severe symptoms of COVID-19.

It is also important that people with sickle cell avoid any possible triggers.

Immunocompromised state from solid organ transplant

Organ transplants can cause a person to be immunocompromised or have a weakened immune system. This can increase the risk of serious illness due to COVID-19.

An individual in this situation should continue taking any prescribed medicines or treatments. The CDC recommends having at least a 30-day supply of medication.


People who have a body mass index (BMI) of more than 30 may be at increased risk of serious illness due to COVID-19.

There has not been much research into how COVID-19 affects pregnant women and babies.

The sections below will discuss what researchers do know.

Pregnant women

Pregnant women experience changes in their immune system that may increase their risk of developing severe illness from respiratory viruses such as the flu.

According to the CDC, however, healthcare experts do not currently know if pregnant women have a greater chance of getting sick from COVID-19 than the people in general.

That said, pregnant women should take precautions to protect themselves against COVID-19 and report any possible symptoms to their healthcare provider.


A recent report suggests that mother-to-child transmission during pregnancy is unlikely for SARS-CoV-2.

As it is currently unknown whether or not newborn babies with COVID-19 are at increased risk of severe complications, the CDC recommend that infants born to mothers with suspected or confirmed COVID-19 go into isolation.

This precaution may prevent a newborn from passing on the virus in a nursery to other infants, family, or staff.

The COVID-19 incubation period, or the time between catching the virus and starting to show symptoms, is often around 5–6 days, but it can range from 1–14 days.

The 2019 coronavirus spreads primarily through close person-to-person contact.

When someone who has the infection coughs or sneezes, tiny droplets containing the virus spray into the air from their nose or mouth. Anyone within 6 feet (2 meters) of someone who has the virus is close enough to potentially contract it.

A recent study in the New England Journal of Medicine shows that the virus can survive in droplets for up to 3 hours after a person coughs it out into the air.

However, it is important to note that the tests in this study used aerosol machines under laboratory settings rather than human breath. The aerosol from a person’s cough may not stay in the air for as long.

The study also found that the virus survives for longer on surfaces. It can last for up to 24 hours on cardboard and for as long as 72 hours on plastic and stainless steel surfaces.

COVID-19 can spread when a person touches their eyes, nose, or mouth after touching a surface or object that the coronavirus has contaminated.

It is also possible for people who have no symptoms of infection to pass the virus on to others.

Learn more about how the 2019 coronavirus spreads here.

People can protect themselves from contracting the virus and prevent its spread by following the precautions below.

  • Wash the hands: Washing the hands often with soap and water for at least 20 seconds is the most important practice. When soap and water are not available, use hand sanitizer. Some key times to wash the hands include before eating and preparing food, after using the bathroom, after being in public, and when the hands are visibly dirty.
  • Avoid touching the eyes, nose, and mouth: This prevents the virus from entering the body.
  • Keep a distance: People should keep a distance of 6 feet (2 meters) between themselves and other people.
  • Practice good public hygiene: Cover all coughs and sneezes with a tissue or elbow, not the hands, and dispose of the tissue immediately.
  • Clean surfaces often: Clean and disinfect frequently touched objects and surfaces, such as tabletops, counters, and doorknobs.
  • Avoid sharing: Avoid sharing personal household items, such as cups and towels.
  • Stay home: Only go outside if it is absolutely necessary, for either short periods of exercise or to buy vital items, such as food and medication.
  • Get vaccinated: Get vaccinated for the flu, if possible.
  • Use a cloth face covering: In the U.S., the CDC recommend that everyone should wear a cloth face covering in public places where it is difficult to stay 6 feet (2 meters) away from others. This will help slow the spread of the virus by people who do not know that they have it. People should continue to wash their hands often and practice physical distancing. Learn how to make a mask at home here.

If a person believes that they have had exposure to the virus and develop serious symptoms, such as a fever, a cough, or difficulty breathing, they should contact a healthcare provider to determine whether a medical evaluation or additional care is necessary.

If the symptoms are not severe, a person should begin self-isolation. No other action is necessary at this time. To avoid spreading COVID-19 to others, they should:

  • stay home unless a doctor advises them to seek medical care, or if there is an emergence
  • isolate themselves in a separate room, away from others in the household
  • wear a face mask or scarf to prevent any saliva or respiratory droplets from spreading to others
  • call ahead before visiting a doctor’s office or urgent care center if the symptoms become severe
  • avoid public transport, cabs, and ride sharing unless absolutely necessary

At this time, there is no cure for COVID-19. Treatment is supportive, and healthcare professionals have designed it to provide relief from the symptoms.

Supportive treatment measures are similar to those for a cold or flu. They may include:

  • getting plenty of rest
  • drinking plenty of fluids and eating small but frequent nutritious meals
  • taking acetaminophen for pain and fever

Anyone with COVID-19 should contact a doctor or healthcare provider if their symptoms worsen.

At this time, the situation regarding COVID-19 is constantly evolving. Confirmed cases, survival, death rates, and overall outlook all seem to vary greatly, depending on where a person lives, among other factors.

For up-to-date news and statistics, see our live COVID-19 updates page.

COVID-19 is a highly contagious respiratory disease that the virus SARS-CoV-2 causes.

The majority of people with COVID-19 will experience a mild illness, similar to the flu. However, older adults and people with certain conditions may be more at risk of developing a more serious illness.

There is currently no cure for COVID-19. Treatment aims to relieve the impact of the symptoms.

Prevention strategies, such as physical distancing, frequent hand washing, and not touching the face, can help protect individuals from the 2019 coronavirus.