RELATED: The CDC Says This Delayed Vaccine Side Effect Is Showing Up More Often Now. On June 10, the CDC announced that it will hold an emergency meeting with its advisers on June 18 to discuss the recent increase in myocarditis and pericarditis following immunization with an mRNA COVID vaccine. The CDC defines myocarditis as inflammation of the heart muscle and pericarditis as inflammation of the outer lining of the heart. These conditions occur when the body’s immune system causes inflammation as a response to a trigger, such as an infection. According to the CDC, the adverse effects are occurring “mostly in male adolescents and young adults age 16 years or older … typically within several days after COVID-19 vaccination.“ae0fcc31ae342fd3a1346ebb1f342fcb It’s important to note that this side effect remains rare, but it’s happening more frequently than expected. As of May 31, of the 141 million people that had been vaccinated, 226 cases reported to the CDC met the working definition of myocarditis or pericarditis. And though the majority have recovered, 41 had ongoing symptoms, 15 were still in the hospital, and three were in the intensive care unit, as of the CDC’s May 31 presentation. RELATED: For more up-to-date information, sign up for our daily newsletter. Since the adverse effect is quite uncommon, the CDC still urges people to get vaccinated. “The known and potential benefits of COVID-19 vaccination outweigh the known and potential risks, including the possible risk of myocarditis or pericarditis,” the agency says. “Also, most patients with myocarditis and pericarditis who received care responded well to medicine and rest and quickly felt better.” Per the CDC, you should watch for the signs of myocarditis and pericarditis after vaccination. Symptoms of these conditions include chest pain, shortness of breath, or feelings of having a fast-beating, fluttering, or pounding heart. If you experience any of these symptoms in the week following your vaccination, the CDC urges you to seek medical care. RELATED: Dr. Fauci Just Made This Major Admission About the CDC Mask Guidance.