CDC Finds Recovery Common From Rare Vaccine-Related Myocarditis

Most patients who experience a rare myocarditits following mRNA vaccination against COVID-19 fully recover and regain pre-pandemic quality-of-life, according to a Centers for Disease Control and Prevention (CDC) study of outcomes at least 90 days after the diagnosis.

Case descriptions have suggested that outcomes from the rare occurrence of myocarditis after vaccination, found more often in young adult males, are more favorable than those associated with the viral infection.Although these reports describe symptoms resolving prior to, or soon after discharge from short hospital stays, the CDC investigators note that the course in the intermediate term after diagnosis is unclear.

"Data on follow-up prognoses of adolescents and young adults diagnosed with myocarditis after mRNA COVID-19 vaccination are scarce," Ian Kracalik, PhD, and colleagues of the CDC COVID-19 Response Team, US CDC, Atlanta, GA, observed.

To ascertain outcomes that may persist or emerge over longer term, Kracalik and colleagues conducted the largest surveillance of these patients to date, with follow-up surveys of patients and/or their health care providers at least 90 days after the diagnosis (median 143 days).

Among the tests ofcardiac status and function, the investigators sought novel data for post-myocarditis scarring by the presence of late gadolinium enhancement, and residual edema in the cardiac MRI. In addition, they elicited, and compared EuroQol health-related quality-of-life measures to the ratings published in US populations from before, and early in the COVID-19 pandemic.

Data were collected for 519 patients who were at least 90 days post-myocarditis onset; with 126 contacted by patient survey, 162 via their health-care provider survey, and 231 through both surveys.The median patient age was 17 years, with 88% male.

The investigators report that 320 (81%) of the 393 patients with a health-care provider assessment were determined to have recovered from the myocarditis; with 268 [68%] of 393 patients cleared for all physical activity at follow-up.There were however, 104 (26%) prescribed daily medication related to myocarditis.

Of 249 patients who completed the quality-of-life portion of the survey, 4 (2%) reported problem with self-care, 13 (5%) with mobility, 49 (20%) with performing usual activities, 74 (30%) with pain, and 114 (46%) with depression. The investigators calculated the mean weighted quality-of-life measure (0.92, [SD 0.13]) to be similar to a pre-pandemic US population value of 0.92 (SD 0.13), and significantly higher than an early pandemic US population value of 0.75 (SD 0.28).

Most patients had improvements in cardiac diagnostic marker and testing data, including normal or back-to-baseline troponin concentrations, echocardiograms, electocardiograms, exercise stress testing, and ambulatory rhythm monitoring.An abnormality was noted among 82 (54%) of the 151 patients with follow-up cardiac MRI, but evidence of myocarditis from late gadolinium enhancement and/or edema was uncommon (20 [13%] of 151 patients).

In accompanying commentary, Enrico Ammirati, MD, PhD, De Gasperis Cardio Center, Niguarda Hospital, Milano, Italy and Leslie Cooper Jr, MD, Department of Cardiovascular Medicine, Mayo Clinic, Jacksonville, Florida noted that the survey responses from patients described more symptoms of myocarditis than did those from their providers.

"This comparison highlights the need to seek patient-reported outcomes rather than rely only on physiological or biochemical metrics to identify full recovery," Ammirati and Cooper said.

They also emphasize that the finding of less severe and less common myocarditis following mRNA vaccination than has historically been associated with the viral infection should "help to resolve the dilemma between vaccination and no vaccination."

"Health care providers and individuals should be reassured by the high rate of cardiac recovery in mRNA COVID-10 vaccine related myocarditis," Ammirati and Cooper indicate.