Sequelae of mRNA vaccine

The latest! Young males aged 16-24 who received the mRNA vaccine were prone to myocarditis sequelae

Multi-country pharmacovigilance reports, health system surveillance studies, and case series have shown an association between sarS-COV-2 vaccination and myocarditis and pericarditis, an association that became more pronounced after the second dose of mRNA vaccine BNT162b2 and mrNA-1273. And serious myocarditis or pericarditis can lead to chronic heart failure or even death, the harm to health can not be ignored.

On June 25, 2021, the FDA issued a warning to the public regarding an increased risk of myocarditis and pericarditis (inflammation of the tissue surrounding the heart) for Pfizer's and Moderna's COVID-19 mRNA vaccines based on an adverse event report from the U.S. Centers for Disease Control and Prevention (CDC).

In December 2021, according to a Danish population study of nearly 5 million published by BMJ, vaccination with mrNA-1273 was associated with a significantly increased risk of myocarditis or pericarditis in 12 to 39 years of age, but the absolute incidence was low. The increased risk in women was significantly associated with BNT162b2 vaccine [1]. This study, led by Anders Husby of Imperial College London, United Kingdom, analyzed the association between SARS-COV-2 vaccination and myocarditis and pericarditis by collecting data from the Danish national vaccination registry.

In response, the WHO and the European Medicines Agency have said that the benefits of vaccination outweigh the risks, considering that vaccines can prevent severe COVID-19 cases and reduce mortality. On February 9 of this year, the American College of Cardiology publicly stated that although vaccine-associated myocarditis is a real side effect of the mRNA vaccine, given that such cases are rare, the benefits of vaccination still outweigh the risks [2].

JAMA Cardiology: 16-24 years old
Young men were at highest risk of receiving the mRNA vaccine

Previous case reports and surveillance data from the United States, Israel, and Canada suggest an increased risk of myocarditis after vaccination with sarS-COV-2 mRNA vaccine, higher after the second dose, and more pronounced in young men. Data from Canada and France suggest that there are more cases of myocarditis after mrnA-1273 than after BNT162b2 vaccination, but the details remain to be clarified.

A Cohort Study entitled "SARS-CoV-2 Vaccination and myelocardia ina Nordic Cohort Study of 23 Million Residents" was published by JAMA Cardiology. Analysis of 23.1 million participants in four Nordic countries -- Denmark, Finland, Norway and Sweden -- found that for individuals who received two doses of the same vaccine, young men between the ages of 16 and 24 had the highest risk of developing myocarditis after the second dose.

Relationship between vaccination and myocarditis during risk period

During the 28-day risk period after vaccination, 105 and 115 cases of myocarditis were observed after the first and second doses of BNT162b2, respectively. 15 and 60 cases of myocarditis were found after the first and second doses of mrNA-1273, respectively.

In young men aged 16 to 24 years, the adjusted IRR for myocarditis was 5.31 (95% CI, 3.68-7.68) after the second dose of BNT162b2 and 13.83 (95% CI, 8.08-23.68) after the second dose of mrnA-1273. Vaccination rates for young men were lower than for women (Figure 2);

After comparing IRR data across age groups, the researchers found that young men aged 16 to 24 years who received BNT162b2 and mrnA-1273 vaccine had a higher risk of myocarditis and a higher risk of the second dose than the first.

Relationship between vaccination and pericarditis during risk period

During the 28-day risk period, there were 7.39 pericarditis events per 100,000 vaccinated men aged 16 to 24 years who received the second dose of mrNA-1273. The pattern of male pericarditis was similar to that found in myocarditis, but the overall IRR was lower. Pericarditis is rare in women aged 12 to 39 years.

These studies showed a higher incidence of myocarditis and pericarditis within 28 days of sarS-COV-2 mRNA vaccination compared with non-vaccination. The risk of myocarditis and pericarditis was highest during the first 7 days of vaccination and was more pronounced after the second dose. The second dose of mrnA-1273 had the highest risk of myocarditis and pericarditis, with the highest risk in young men aged 16 to 24.