MIS-C-Data Multisystem Inflammatory Syndrome in Children (MIS-C) Data

Multisystem Inflammatory Syndrome in Children (MIS-C) Data

What is Multisystem Inflammatory Syndrome in Children (MIS-C)?

Multisystem Inflammatory Syndrome in Children, or "MIS-C", is a rare health condition that can occur in children and teens under 21 years of age who were infected with SARS-CoV-2 (the virus that causes COVID-19). Children with MIS-C get inflammation in different parts of the body ("organ systems") up to eight weeks after being infected with SARS-CoV-2. This inflammation can occur whether the child did or did not have symptoms of COVID-19. Organ systems that can be affected by MIS-C can include: the heart, lungs, kidneys, brain, skin, eyes, and/or gastrointestinal organs. Because it is caused by SARS-CoV-2, MIS-C is a new condition that was first reported in April, 2020.

MIS-C Cases, California

MIS-C case reporting and abstraction may be delayed due to limited capacity at local health departments and as CDPH assesses data to ensure patients meet the MIS-C case definition. Surveillance data are preliminary and subject to change.

CDPH data was last updated 11/14/2022. Data are updated on the second Monday of each month. 

MIS-C & COVID-19 Cases in California by Week of Onset

MISC_Epicurve_11.14.22There were a total of 1,036 reported MIS-C cases in California from March 23, 2020 (when tracking began) to November 14, 2022. Because MIS-C case numbers tend to rise around three to eight weeks following a surge in COVID-19 cases, recent increases in COVID-19 in the community may not yet be reflected in MIS-C case numbers. Please note that the MIS-C cases have been scaled for visibility on the above graph. The graph has been updated to show <21 COVID-19 cases only.

Download the MIS-C & COVID-19 Cases in California by Week of Onset (Excel).

MIS-C Disease Severity

While overall mortality from MIS-C remains low in California (under 1%), the disease can be severe. Approximately half of children with MIS-C in California were admitted to the ICU.

MIS-C Demographic and Disease Severity Highlights, California & United States

Variables
California*  United States**
Cases1,036
9,073
Deaths9
74
ICU Admission48.2%--
Median Age8 years
9 years
SexMale (62.4%)Male (60.32%)

 

Cumulative MIS-C Case Rate by Health Officer Region

The cumulative MIS-C case rate for California is 9.52 per 100,000 persons. Regional differences in case burden may be due to several factors including level of community transmission, health inequities, more awareness and reporting by health care providers, and properties of the virus that we still are learning about. Since all confirmed cases of MIS-C require hospitalization, these different regional impacts may strain an already impacted health system from COVID-19.

Health Officer RegionCountiesMIS-C Case Rate Per 100,000 persons1
CaliforniaAll9.52
Bay AreaAlameda, Contra Costa, Marin, Monterey, Napa, San Francisco, San Mateo, Santa Clara, Santa Cruz, Solano, Sonoma5.08
Greater SacramentoAlpine, Amador, Butte, Colusa, El Dorado, Nevada, Placer, Plumas, Sacramento, Sierra, Sutter, Yolo, Yuba6.66
Northern CaliforniaDel Norte, Glenn, Humboldt, Lake, Lassen, Mendocino, Modoc, Shasta, Siskiyou, Tehama, Trinity4.02
San Joaquin ValleyCalaveras, Fresno, Kern, Kings, Madera, Mariposa, Merced, San Benito, San Joaquin, Stanislaus, Tulare, Tuolumne12.53
Southern CaliforniaImperial, Inyo, Los Angeles, Mono, Orange, Riverside, San Bernardino, San Diego, San Luis Obispo, Santa Barbara, Ventura10.82

1 The population denominators by region come from the California Department of Finance's population projections for 2020.


MIS-C Comorbidities, California 

About half of children and teens who had MIS-C had no known previous health conditions or "comorbidities" (54%). The other half of children with MIS-C had a known or reported existing medical condition, the most common being reported as "other"2 and obesity. About 1 in 6 cases of children with MIS-C had two or more underlying medical conditions.

Comorbidity1
Percentage with Comorbidity (%)

Other22

29.6%

​Obesity

​22.4%

​Lung Disease

7.6%

​Other Congenital Malformation

2.9%

​Seizures

​2.2%

​Congenital Heart Disease

​2.0%

​Malignancy

​1.5%

​Diabetes

​0.8%

​Sickle Cell

​0.7%

1Includes all comorbidities on the CDC's MIS-C Case Report Form (PDF).

2The “other” category is a free text variable, and includes reporting of conditions such as ADHD, depression, autism spectrum disorder, hyperlipidemia, hypertension, eczema, irregular heart rate, thalassemia, sickle cell trait, overweight but not obese, hypothyroidism.


MIS-C Cases by Race/Ethnicity, California & United States

Like COVID-19, there’s a disproportionate number of cases of MIS-C among Latino and African American children and teens.  In California, Latino children and teens make up the largest proportion of MIS-C cases and are overrepresented compared to the total population of Latino people under age 21 in California.

Race/Ethnicity Percent of MIS-C Cases in California (%)* Percent of California Population <21 Years (%) Percent of MIS-C Cases in U.S. (%)**
Latino54.7%
47.7%26.1%
White
17.4%
29.2%
35.1%
African American9.3%5.6%
30.3%
Other8.2%
--
3.6%
Asian
4.5%12.9%
2.7%
Unknown
4.6%--
--
Multi-Race
<1.0%
3.8%
<1.0%
Native Hawaiian and Other Pacific Islander<1.0%<1.0%<1.0%
American Indian<1.0%<1.0%<1.0%

 

MIS-C Cases by Healthy Places Index (Estimated by Census Tract), California

The COVID-19 pandemic has highlighted health disparities and led to a disproportionate number of cases in certain communities, especially communities of color. Social determinants of health, such as lower median income, decreased access to health care, and more crowded housing, interact to increase the risk of COVID-19 infection. Since MIS-C can occur after a COVID-19 infection, the same communities that are more severely impacted by COVID-19 also experience more cases of MIS-C.

The California Healthy Places Index (HPI), a tool developed by the Public Health Alliance of Southern California, helps to explore the community conditions that predict life expectancy. Applying the HPI to MIS-C cases in California reveals the vast inequities between those living in healthier community conditions (more advantaged groups) compared to those living in less healthy community conditions (less advantaged groups). 

Of the data available, about 70% of MIS-C cases were in the two lowest advantaged quartiles (scoring lowest on the HPI), and about 43.0% of MIS-C cases were in the least advantaged quartile alone, meaning a large percentage of MIS-C cases were from residents of less advantaged communities.

Healthy Place Index (HPI) Quartiles
Percent  of MIS-C Cases (%)
Least Advantaged
(Quartile 1)
43.0%
Somewhat Advantaged
(Quartile 2)
26.8%
Advantaged
(Quartile 3)
17.5%
Most Advantaged
(Quartile 4)
9.9%
Missing2.8%

Reporting MIS-C Cases

In order to get a better picture of the burden of MIS-C in California, health care professionals and hospital infection personnel should report all cases that meet the CDC definition of MIS-C using the COVID-19 Confidential Morbidity Report (CMR) (PDF - note MIS-C under “Additional Remarks”) to their local health department (LHD). 

To report MIS-C cases, ensure cases meets MIS-C CDC definition, complete CMR form and send completed CMR to your LHD

MIS-C Resources for Health Professionals


*California MIS-C Data last updated by CDPH on 11/14/2022