- A Canadian study shows that myocarditis and pericarditis after COVID-19 mRNA vaccinations are extremely rare.
- This research also suggests that spacing second doses to 30 days and offering Pfizer rather than Moderna vaccines may reduce the risk of developing these conditions in men aged 12 to 29.
- Experts point out that developing COVID-19 poses a greater risk of myocarditis and pericarditis than being vaccinated.
Experts from the University of Alberta in Canada analyzed the evidence on the risk of myocarditis and pericarditis after vaccination against COVID-19 and found that the risk is low, including in young men. These conditions, usually caused by viral infections, involve inflammation of heart tissue.
The results confirm that the problems occur more frequently in young men soon after a second dose of the mRNA vaccine.
Most cases have been mild, and the risk appears to be higher after receiving Moderna’s mRNA vaccine than Pfizer’s counterpart.
The researchers suggest that using Pfizer rather than Moderna and spreading out the dosing intervals could reduce the risks for younger people.
This study appears in the
Myocarditis refers to inflammation of the heart muscle and pericarditis occurs when there is inflammation of the sac surrounding the heart. Both conditions are usually caused by a viral infection.
The conditions are rare but serious. Fortunately, most people make a full recovery.
A slight increase in cases after COVID-19 mRNA vaccinations has raised concerns among medical and public health officials.
The reports first emerged in April 2021, leading to monitoring of side effects after vaccination with mRNA vaccines from Pfizer and Moderna.
University of Alberta pediatric and cardiology specialists analyzed more than 8,000 cases after combing through 46 studies.
They began to investigate the records of people of all age groups and focused on people between the ages of 0 and 39. According to the researchers, incident rates among adults aged 40 and older were “very low to zero.”
What is their frequency?
The researchers noted that overall rates of myocarditis are 1 to 2 cases per 100,000 person-years in the United States. Person-years is a measure used in prospective studies where researchers consider the number of participants involved and the amount of time each person spends on the study. If a study followed 100 people for 20 years, the research would contain 2,000 person-years of data.
The study found that myocarditis rates after COVID-19 vaccination are 0.2 per million people – and 1.4 per million for pericarditis.
They found that adolescent and young adult males had the highest incidences of myocarditis after receiving mRNA vaccines against SARS-CoV-2. The results are consistent with historical trends for this condition.
Male teens ages 12 to 17 had 50 to 139 cases per million, and adult males ages 18 to 29 had 28 to 147 cases per million.
Modern vs. Pfizer
Medical New Today discussed this study with Dr. Jorge Moreno, assistant professor of medicine at the Yale School of Medicine. He did not participate in the study.
Dr. Moreno agreed that cases of myocarditis and pericarditis related to the COVID-19 vaccine are rare.
He also pointed out that “COVID, the disease, can also [cause] myocarditis, and that’s much more likely than the vaccine itself [causing it].”
Dr. Moreno mentioned that some European countries prefer the Pfizer COVID-19 vaccine, which appears to have a lower myocarditis risk than the Moderna vaccine.
However, he added, “the FDA and CDC here in the United States did not find the difference significant enough to make this recommendation.”
Change dosing schedule?
The researchers also found that the risk of myocarditis or pericarditis may be lower if people receive their second dose of the vaccine more than 30 days after the first.
Data specific to young men suggest that increasing dosing intervals beyond 56 days may significantly reduce rates of these conditions.
Dr. Moreno said more studies are needed to assess the idea of spacing vaccine doses.
The authors pointed out that data on risk factors were limited. They hope that future studies will include tissue samples and long-term follow-up to “improve understanding of the mechanism[s]” drive heart disease.
The COVID-19 landscape is rapidly changing, calling for ever-changing research.
In a link
DTM also spoke with Dr. Jeffrey J. Hsu, a cardiologist at UCLA Health, regarding the current study. He did not participate in the research.
Dr. Hsu said he was concerned that problems with myocarditis and pericarditis may have deterred some people from getting vaccinated:
“While studies like this show that these conditions rarely occur after vaccination, my concern is that the results of these studies are either misinterpreted or distorted when reported to the public.”
Dr. Hsu and Dr. Moreno emphasized that conveying information with empathy is the most effective strategy for encouraging vaccine hesitants.
Dr Hsu said: “We now have much more data on the benefits and risks of vaccination compared to the start of the pandemic and it is important that clinicians clearly communicate our latest understanding of the impact of vaccination. . Additionally, for patients who are reluctant to proceed with vaccination, I have found it helpful to spend time understanding their specific reservations.
Dr. Moreno explained why some people remain oblivious or skeptical about the effectiveness and safety of vaccines.
For example, a considerable proportion of the Hispanic population faces a language barrier. The assistant professor added: “I think there is a lot of mistrust in the healthcare system because of years of problems that have arisen, whether it is access to healthcare [or] insurance issues.
Dr. Moreno also said that reaching many Hispanic and Black people requires a deeper understanding of cultural differences.
Dr Hsu commented: “For some people, it is clear that nothing will change their position on vaccination, while others may simply seek clearer information from a reliable source, such as their doctor.”