NCIRS study assesses clinical progression of myocarditis linked to mRNA COVID-19 vaccination

Long-term follow-up data from a new NCIRS study have revealed low hospitalisation rates, improved health-related quality of life over time and no deaths among individuals with myocarditis associated with mRNA COVID-19 vaccination who were followed up over 18 months following their diagnosis. 

NCIRS researchers followed 256 individuals in Australia who had confirmed or probable myocarditis – inflammation of the heart muscle – following mRNA COVID-19 vaccination over an 18-month period to assess their clinical progression and health-related quality of life.

The most commonly reported symptoms at each follow-up period (discharge, 3–6 months, 12–18 moths) were chest pain/pressure/discomfort, fatigue/lethargy, shortness of breath and palpitations. 

The majority (65%) of individuals reported no ongoing symptoms at 12–18 months. Those who still had symptoms (35%) were more likely to have ongoing exercise restrictions and need continued medication. The study also found that older individuals and females were significantly more likely to report ongoing symptoms.

Although individuals with ongoing symptoms reported poorer health-related quality of life compared to those without symptoms, their health-related quality of life scores (measured by EuroQol 5-dimension, 5-level [EQ-5D-5L] questionnaire and EuroQol Visual Analog Scale [EQ-VAS]) were still comparable to the general population, explained Dr Lucy Deng, study lead and Senior Medical Officer Vaccine Safety at NCIRS.

‘This is the longest and most comprehensive prospective follow-up study of individuals diagnosed with myocarditis following mRNA COVID-19 vaccination to date that includes direct assessment of the individuals’ clinical progression and health-related quality of life.’

‘Our study suggests that while a proportion of mRNA COVID-19 vaccine-associated myocarditis cases remained symptomatic at 12–18 months, they were clinically mild compared with myocarditis caused by viral infections – including SARS-CoV-2 – and the subsequent impact on health-related quality of life was also mild,’ concluded Dr Deng.

The study findings, published in npj Vaccines, support the ongoing use of mRNA COVID-19 vaccines in at-risk individuals to prevent severe disease caused by SARS-CoV-2 infection.

The study forms part of the adverse event of special interest (AESI) long-term follow-up program that is that is following up individuals who experienced AESIs after receiving a COVID-19 vaccine to help gain a greater understanding of the characteristics, progress and outcomes of these adverse events.

Additional research examining the long-term follow up of individuals diagnosed with thrombosis and thrombocytopenia syndrome (TTS) linked to viral vector (AstraZeneca) COVID-19 vaccination is currently underway and will be published later this year.
 

View the study