Multisystem inflammatory syndrome in children (MIS-C) and COVID-19

Multisystem inflammatory syndrome in children (MIS-C) is a rare but serious illness linked to coronavirus disease 2019 (COVID-19).

Most children with COVID-19 have only mild illness. But with MIS-C, the body's immune system reacts too strongly. It causes damage to the body.

MIS-C is rare. It usually happens within two months after a child has COVID-19 or has been around someone who had the illness.

Most children with MIS-C get better over time. But some kids quickly get worse. MIS-C can be a life-threatening illness and, sometimes, causes death.

MIS-C causes serious symptoms that are often treated in the hospital. Not all children have the same symptoms.

If no other diagnosis fits, healthcare professionals may diagnose MIS-C if a child has:

• Had COVID-19 or was in close contact with someone who recently had it.
• A fever, which may last 4 to 6 days.
• A blood test that shows a high level of inflammation in the body.
• Symptoms of health issues within two other organ systems.

Examples of symptoms in other organ systems include:

• Trouble with how the heart pumps blood or damage to heart arteries.
• A rash, red eyes, and redness or swelling of the lips or tongue. Children also may have swollen hands or feet.
• Belly pain, vomiting or diarrhea.
• Blood test results outside the reference range. For example, too many immune cells or too few blood cells called platelets.
• Shock, which is a bodywide response to the immune system that affects blood vessels and the heart.

Emergency warning signs of MIS-C

Call 911 or your local emergency number to get help right away if your child has:

• Severe belly pain.
• Pain or a feeling of pressure in the chest.
• Problems breathing.
• Gray or blue skin, lips or nail beds.
• New confusion.
• Trouble waking up or staying awake.

When to see a doctor

Get care right away if your child has severe belly pain, pain or pressure in the chest, trouble breathing, new confusion, or trouble waking up or staying awake. Take your child to the nearest emergency room or call 911 or your local emergency number.

If your child isn't severely ill but has symptoms of MIS-C, contact your child's healthcare professional right away for advice.

The exact cause of MIS-C is not known. Many children with MIS-C have had a recent infection with the COVID-19 virus. Some may have a current infection with the virus.

MIS-C most often affects children ages 5 to 12. Older and younger kids can get MIS-C but it's rare.

MIS-C is a possible complication of COVID-19. Without quick diagnosis and treatment, MIS-C can cause serious symptoms in vital organs, such as the heart. Rarely, MIS-C may cause lasting health issues or death.

Getting a COVID-19 vaccine may help prevent multisystem inflammatory syndrome in children. The 2025-2026 COVID-19 vaccines available in the United States include shots from Moderna, Pfizer-BioNTech and Novavax. Each vaccine is approved for children based on their age and health.

Moderna COVID-19 vaccine 2025-2026 formulas

• Spikevax. This vaccine is approved for children age 6 months and older who have a risk of serious COVID-19 illness.
• Mnexspike. This vaccine is approved for children age 12 years and older who have a risk of serious COVID-19 illness.

Pfizer-BioNTech COVID-19 vaccine 2025-2026 formula

• Comirnaty. This vaccine is approved for children age 5 years and older who have a risk of serious COVID-19 illness.

Novavax COVID-19 vaccine 2025-2026 formula

• Nuvaxovid. This vaccine is approved for children age 12 years and older who have a risk of serious COVID-19 illness.

The vaccine protects against serious illness, the need for hospital care due to COVID-19 and the risk of dying of COVID-19. Serious side effects from the COVID-19 vaccine are extremely rare. Because of that, even healthy people benefit from the COVID-19 vaccine, which lowers the risk of serious illness at a similar rate to the flu vaccine.

Children ages 6 months to 23 months who get vaccines for the first time are up to date after two doses of Spikevax, spaced at least four weeks apart. Most people age 2 and older will be up to date after one dose of the 2025-2026 COVID-19 vaccine from any vaccine maker.

The COVID-19 vaccine can be given to children on the same day as other vaccines if the timing is correct.

Control the spread of the virus

If many people in your area have COVID-19, wear a well-fitting mask indoors in public places. Do not put a face mask on a child younger than age 2 or a child with a disability who can't safely wear a mask.

Keep air moving by opening windows or doors or by using fans. Air filters can help clean the air as well. Stay apart from anyone who is sick or has symptoms. In crowded indoor spaces, spread out if you can, especially in places with poor airflow. Always keep hands clean, and regularly clean and disinfect your home.

Multisystem inflammatory syndrome in children (MIS-C) is diagnosed based on a child's symptoms and on ruling out other health issues.

MIS-C can look like other illnesses, such as:

• Kawasaki disease.
• Toxic shock syndrome.
• Appendicitis.
• Macrophage activation syndrome.
• Severe COVID-19.

To test for COVID-19, your healthcare team may use a blood test or a swab of the nose or back of the throat. Or you may be asked about COVID-19 infections among a child's close contacts. Most kids who get MIS-C have had a link to the virus that causes COVID-19 within two months of getting sick.

To diagnose MIS-C, the healthcare team may use lab tests, such as blood and urine tests. Children also may have imaging tests, such as a chest X-ray, an echocardiogram, an abdominal ultrasound or a CT scan.

Children with multisystem inflammatory syndrome are treated in a hospital. Some may need special care, for example, in a pediatric intensive care unit. Treatment depends on how sick the child is and which organs are affected.

Medicines used to treat MIS-C may include:

• Antibiotics.
• Steroids.
• Intravenous immunoglobulin, a blood product made up of antibodies.
• Medicines to lessen cytokines, which are proteins that cause inflammation.
• Blood pressure medicines to treat low blood pressure related to shock or to help with heart function.
• Medicines that lower the risk of blood clots, such as aspirin or heparin.

Supportive care may include:

• Oxygen to make breathing easier.
• A ventilator, to help a child breathe.
• Extracorporeal membrane oxygenation (ECMO). With ECMO, a machine that does the work of the heart and lungs.

MIS-C isn't contagious. But there's a chance that your child could have COVID-19 or another type of contagious infection. So the care team uses infection control measures while caring for your child.

If your child has multisystem inflammatory syndrome, you may feel scared and anxious. Because MIS-C is rare, you may not know anyone who has gone through it. Talk with friends or family about how you feel. If you need more support, ask for help from a mental health professional. This person can help you manage your feelings.

If your child has emergency warning signs of MIS-C or is severely sick, take your child to the nearest emergency room. Or call 911 or your local emergency number. Remember to wear a mask to protect yourself and others. If your child's symptoms are not severe, contact your child's healthcare professional.

What you can do

When you make the appointment, ask if there's anything you need to do in advance. Make a list of:

• Your child's symptoms, including when they started.
• Key personal information, including major stresses, recent life changes and family medical history.
• All medicines, vitamins and other supplements your child takes, including the dosages.
• Any group activities your child recently took part in, including the dates.
• Questions to ask the healthcare professional.

What to expect from your doctor

Your healthcare professional is likely to ask you, and your child, depending on your child's age, several questions, such as:

• When did the symptoms begin?
• How severe are the symptoms?
• Has your child been tested for COVID-19?
• Has your child been exposed to anyone who tested positive for the COVID-19 virus?
• Does your child go to school?
• Has your child been involved in any recent group activities, such as sports?
• Who has your child been in close contact with recently?

Preparing for the appointment makes sure you have time to get all of your questions answered. It helps you learn what the next steps are and why they're important.