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What Is COVID-19?

At the end of 2019, a new type of coronavirus, called SARS-CoV-2, began making people sick with flu-like symptoms. The illness it causes is called coronavirus disease-19 — COVID-19, for short. The virus spreads easily and has affected people all over the world.

Everyone 6 months of age or older should stay up to date on their COVID-19 vaccine. The updated vaccine protects against the variants that are now most common.

What Is a Pandemic?

When a disease affects many more people than expected in a community or other limited area, it’s called an epidemic. If the disease spreads to many countries or around the world, it’s called a pandemic.

The worldwide spread of COVID-19 became a pandemic. Pandemics can have surges or waves, which is when even more people become infected. If a virus spreads easily, surges are most likely when infected people gather and aren’t wearing masks or aren’t vaccinated. Surges are also more likely if the virus changes to a more contagious form.

Sometimes a disease can become endemic. This means the disease is always around in a certain community or limited area, but it doesn’t affect people in unexpected surges or waves. When a disease is endemic, it spreads in a stable and predictable way. The flu and the common cold are both endemic infections. COVID-19 looks likely to become endemic too. The World Health Organization (WHO) declared an end to the COVID-19 global public health emergency in May 2023.

What Are the Signs & Symptoms of COVID-19?

COVID-19 infection can cause a range of symptoms, which can be more serious in some people than others. The most common signs are fever, cough, trouble breathing, and gastrointestinal problems (like bellyache, nausea, vomiting, and diarrhea). Other complaints include headaches, muscle aches, loss of taste and smell, rashes, and cold symptoms. Infants can be fussy or lose their appetite, or have only a fever.

Some people who get the virus don't have any symptoms.

What Is MIS-C?

Some kids might get symptoms caused by inflammation throughout the body a few weeks after they were infected with COVID-19. This is called multisystem inflammatory syndrome in children (MIS-C). It can cause fever and make a child look very sick. And it can affect many different body systems, including the heart, blood cells, blood vessels, skin, eyes, and gastrointestinal system. Common symptoms include stomach pain, diarrhea, vomiting, rash, bloodshot eyes, and dizziness.

MIS-C is a serious condition that can lead to organ damage if not treated quickly. But it’s very rare and most kids fully recover after getting medical care.

What Is Long COVID?

Some people have symptoms that last for a long time (usually more than a month), a condition known as long (or long-haul) COVID or "post-COVID-19 condition." Sometimes these symptoms begin while a person is still sick, but they also can start after someone recovered or after they had an infection with no symptoms. These symptoms can include tiredness, headache, trouble sleeping, trouble breathing, trouble concentrating (“brain fog”), muscle and joint pain, heart palpitations, and changes in their sense of taste and/or sense of smell.

How Does COVID-19 Spread?

SARS-CoV-2 mostly spreads through the air. People can catch it from others who are infected, even those without symptoms. When an infected person breathes, talks, sings, laughs, sneezes, or coughs, tiny droplets go into the air. These can land in the nose, mouth, or eyes of another person, or they can be breathed in. Sometimes the droplets can linger in the air for minutes to hours and travel on air currents. But it seems that the risk of spread is highest when people are close together, when they spend a lot of time together, when they gather indoors, and when the indoor space isn't well-ventilated.

People also might get infected if they touch an infected droplet on a surface and then touch their own nose, mouth, or eyes. But this type of spread is a lot less common.

Experts are still studying other ways that the virus might spread. It has been found in things like poop, tears, and semen, but it doesn’t seem to spread through these. It also doesn’t spread through food or water. Rarely, the virus has been found to spread from people to animals, but the risk of pets spreading the virus to people seems to be very low. The risk of an infected pregnant woman passing the virus to her fetus is also low.

Is COVID-19 Dangerous to Children?

Children are just as likely as adults to get infected with the virus, but they usually seem to have a milder illness and often don’t have any symptoms. But a few kids do get more serious symptoms (such as those with MIS-C), and some have died from COVID-19.

COVID-19 can sometimes lead to myocarditis, an inflammation of the heart muscle. In kids, the most common symptoms include tiredness, trouble breathing, chest pain, or belly pain. Most children recover fully from myocarditis, but sometimes it can be more serious and cause lasting heart damage.

Doctors noticed that more kids than usual were diagnosed with diabetes during the pandemic, especially after being sick with COVID-19. This has also been true for POTS. The reasons for these connections are not yet clear, but studies are underway to learn more.

How Is COVID-19 Treated?

Most people with a mild illness, including kids, don’t need any specific treatment. They get better with rest, liquids, and fever-reducing medicine.

A few kids who are at higher risk for severe COVID-19 can get antiviral medicines to keep them from getting very sick and needing hospital care.

Some people who get severe symptoms will need hospital care, possibly in the ICU. Doctors can closely watch them, give oxygen or IV fluids if needed, and treat any problems. Rarely, they will also give medicines such as antiviral drugs or steroids. Someone who needs extra help to breathe will be connected to a breathing machine (a ventilator).

What Should I Do if My Child Has Symptoms of COVID-19?

Call your doctor if your child has symptoms of COVID-19 or MIS-C, or just isn't feeling well. Tell the doctor if your child has been near someone with COVID-19, or lived in or traveled to an area where lots of people are infected. The doctor can decide whether your child:

Get care right away if your child:

  • has trouble breathing
  • has severe belly pain
  • has pain or pressure in the chest
  • is confused or not making sense
  • has trouble staying awake
  • looks bluish in the lips or face

These symptoms can be warning signs of serious illness.

What Else Should I Know?

To help prevent the spread of germs, it’s always a good idea to:

  • Wash hands well and often. Wash for at least 20 seconds with soap and water or use hand sanitizer with at least 60% alcohol.
  • Avoid people who appear sick.
  • Clean things that get touched a lot (like doorknobs, counters, phones, etc.).

Where Can I Learn More About COVID-19?

Check the CDC and WHO websites for up-to-date information.

Medically reviewed by: Elana Pearl Ben-Joseph, MD
Date reviewed: May 2024