Overview
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.
Symptoms
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.
Causes
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.
Risk factors
MIS-C most often affects children ages 5 to 12. Older and younger kids can get MIS-C but it's rare.
Complications
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.
Prevention
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.