Kaiser Foundation finds Americans more likely to develop rare heart inflammation after the second dose of a COVID-19 vaccine dose.
A new study by the Kaiser Foundation finds Americans more likely to develop rare heart inflammation after the second dose of a COVID-19 vaccine. Myocarditis the medical term for heart inflammation and is a known side effect of viral infections such as COVID-19.
Researchers from Kaiser Permanente Southern California (KPSC) found that less than one out of every one million people who receive the first dose of either the Pfizer-BioNTech or Moderna vaccine will develop the condition within the next ten days.
CDC and its partners are actively monitoring reports of myocarditis and pericarditis after COVID-19 vaccination. Active monitoring includes reviewing data and medical records and evaluating the relationship to COVID-19 vaccination.
Myocarditis is inflammation of the heart muscle, and pericarditis is inflammation of the outer lining of the heart. In both cases, the body’s immune system causes inflammation in response to an infection or some other trigger.
What You Need to Know
Cases of myocarditis reported to the Vaccine Adverse Event Reporting System (VAERS)external icon have occurred, after mRNA COVID-19 vaccination (Pfizer-BioNTech or Moderna), especially in male adolescents and young adults, more often after the second dose, usually within several days after vaccination.
Most patients with myocarditis or pericarditis who received care responded well to medicine and rest and felt better quickly.
Patients can usually return to their normal daily activities after their symptoms improve. Those who have been diagnosed with myocarditis should consult with their cardiologist (heart doctor) about return to exercise or sports. More information will be shared as it becomes available.
Both myocarditis and pericarditis have the following symptoms:
- Chest pain
- Shortness of breath
- Feelings of having a fast-beating, fluttering, or pounding heart
Seek medical care if you or your child have any of these symptoms, especially if it’s within a week after COVID-19 vaccination.
The JAMA Network included Kaiser Permanente Southern California (KPSC) members aged 18 years or older who received at least 1 dose of the BNT162b2 (Pfizer) or mRNA-1273 (Moderna) mRNA vaccine between December 14, 2020, and July 20, 2021.
Healthcare Providers: For additional recommendations and clinical guidance, visit Clinical Considerations: Myocarditis after mRNA COVID-19 Vaccines | CDC