Outcomes at least 90 days since onset of myocarditis after mRNA COVID-19 vaccination in adolescents and young adults in the USA: a follow-up surveillance study

Abstract

Background: Data on medium-term outcomes in indivduals with myocarditis after mRNA COVID-19 vaccination are scarce. We aimed to assess clinical outcomes and quality of life at least 90 days since onset of myocarditis after mRNA COVID-19 vaccination in adolescents and young adults.

Methods: In this follow-up surveillance study, we conducted surveys in US individuals aged 12-29 years with myocarditis after mRNA COVID-19 vaccination, for whom a report had been filed to the Vaccine Adverse Event Reporting System between Jan 12 and Nov 5, 2021. A two-component survey was administered, one component to patients (or parents or guardians) and one component to health-care providers, to assess patient outcomes at least 90 days since myocarditis onset. Data collected were recovery status, cardiac testing, and functional status, and EuroQol health-related quality-of-life measures (dichotomised as no problems or any problems), and a weighted quality-of-life measure, ranging from 0 to 1 (full health). The EuroQol results were compared with published results in US populations (aged 18-24 years) from before and early on in the COVID-19 pandemic.

Findings: Between Aug 24, 2021, and Jan 12, 2022, we collected data for 519 (62%) of 836 eligible patients who were at least 90 days post-myocarditis onset: 126 patients via patient survey only, 162 patients via health-care provider survey only, and 231 patients via both surveys. Median patient age was 17 years (IQR 15-22); 457 (88%) patients were male and 61 (12%) were female. 320 (81%) of 393 patients with a health-care provider assessment were considered recovered from myocarditis by their health-care provider, although at the last health-care provider follow-up, 104 (26%) of 393 patients were prescribed daily medication related to myocarditis. Of 249 individuals who completed the quality-of-life portion of the patient survey, four (2%) reported problems with self-care, 13 (5%) with mobility, 49 (20%) with performing usual activities, 74 (30%) with pain, and 114 (46%) with depression. Mean weighted quality-of-life measure (0·91 [SD 0·13]) was similar to a pre-pandemic US population value (0·92 [0·13]) and significantly higher than an early pandemic US population value (0·75 [0·28]; p<0·0001). Most patients had improvements in cardiac diagnostic marker and testing data at follow-up, including normal or back-to-baseline troponin concentrations (181 [91%] of 200 patients with available data), echocardiograms (262 [94%] of 279 patients), electrocardiograms (240 [77%] of 311 patients), exercise stress testing (94 [90%] of 104 patients), and ambulatory rhythm monitoring (86 [90%] of 96 patients). An abnormality was noted among 81 (54%) of 151 patients with follow-up cardiac MRI; however, evidence of myocarditis suggested by the presence of both late gadolinium enhancement and oedema on cardiac MRI was uncommon (20 [13%] of 151 patients). At follow-up, most patients were cleared for all physical activity (268 [68%] of 393 patients).

Interpretation: After at least 90 days since onset of myocarditis after mRNA COVID-19 vaccination, most individuals in our cohort were considered recovered by health-care providers, and quality of life measures were comparable to those in pre-pandemic and early pandemic populations of a similar age. These findings might not be generalisable given the small sample size and further follow-up is needed for the subset of patients with atypical test results or not considered recovered.

Funding: US Centers for Disease Control and Prevention.

Figure 1

Survey participation of patients with myocarditis after mRNA COVID-19 vaccination reported to VAERS at least 90 days since symptom onset CDC=US Centers for Disease Control and Prevention. VAERS=Vaccine Adverse Event Reporting System.

Figure 2

Self-assessment of health-related quality of life among patients with myocarditis after mRNA COVID-19 vaccination (A) Bar plot of health-related quality of life among patients. Patients were administered the EuroQol 5-dimension 5-severity level questionnaire; for analysis, the five health-related dimensions were dichotomised into the frequency of problems (severity levels 2–5) and no problems (level 1). (B) Violin plot of weighted quality of life measure (using value weights in appendix 1 p 7) converted from each patient health profile from (A) to an index score between 1 (perfect health) and 0 (equivalent to death). (C) Violin plot of patient self-assessed overall health on a scale from 0 to 100 (with 100 representing best possible health and 0 representing the worst possible health). The denominator for the EuroQol questionnaire was 249 respondents. In the violin plots (B, C), the limits of the boxes denote IQR and the horizontal line denotes median values. Whisker endpoints are equal to the maximum and minimum values below or above the median plus or minus 1·5 times the IQR. The width of the outer shape around the box plots indicates the probability density of values or responses with a given result.

Figure 3

Follow-up functional status, biomarker testing, and cardiac imaging in patients at least 90 days since onset of myocarditis after mRNA COVID-19 vaccination Cardiac biomarker testing or imaging findings are from the health-care provider surveys completed for 393 patients. Not all patients received diagnostic testing or imaging and the denominator for each follow-up test is equal to the sum of the normal and abnormal findings; the type of abnormalities identified are not mutually exclusive.

Figure 4

Changes in cardiac biomarker and imaging from the initial encounter and the health-care provider follow-up Testing, including echocardiograms, cardiac MRIs, and troponin concentrations, performed at the time of initial myocarditis diagnosis and at follow-up are not necessarily matched because each patient had testing (or not) at the discretion of the treating health-care providers.