Your Choice of COVID Vaccine Can Increase Your Risk of Myocarditis

In line with heart specialist Man Witberg, the research is reassuring for vaccine security.

The research discovered that Moderna had higher charges of coronary heart irritation than Pfizer, though the general threat remained extraordinarily low.

Compared to the Pfizer BioNTech COVID-19 vaccine, the Moderna Spikevax COVID-19 vaccine has a two- to three-fold greater incidence of myocarditis, pericarditis, or myopericarditis following a second dose; nonetheless, overall cases of heart inflammation with either vaccine are very rare. Males under 40 who got the Moderna vaccine had the greatest incidence of myocarditis, according to the research, which, according to the scientists, may have consequences for choosing certain vaccines for particular populations.

The findings were recently published in the Journal of the American College of Cardiology.

Pfizer BioNTech (BNT162b2) and Moderna Spikevax (mRNA-1273) are the two mRNA COVID-19 vaccines that have been given approval for usage, and as of March 20, 2022, more than 52 million doses of Pfizer and 22 million doses of Moderna have been given in Canada, where this study was conducted. Clinical trials have shown that the vaccines are safe, and monitoring of vaccinated people has shown that side effects are minor and disappear on their own. However, both vaccines have been associated with some rare but serious side effects, most notably myocarditis (inflammation of the heart).

While several studies have been done on each vaccine, few have been done to directly compare the two mRNA vaccines’ safety. The purpose of this research was to compare the risks of myocarditis, pericarditis, and myopericarditis associated with the Pfizer and Moderna COVID-19 vaccines.

People in the study were 18 years old or older and had received two primary doses of either Pfizer or Moderna vaccine in British Columbia, Canada, with the second dose between Jan. 1, 2021, and Sept. 9, 2021. Individuals whose first or second shots were administered outside of British Columbia or had a history of myocarditis or pericarditis within one year prior to the second dose were excluded.

In all, more than 2.2 million second Pfizer doses were given and more than 870,000 Moderna doses. Within 21 days of the second dose, there were a total of 59 myocarditis cases (21 Pfizer and 31 Moderna) and 41 pericarditis cases (21 Pfizer and 20 Moderna). Researchers also looked at rates per million doses and the rate was 35.6 cases per million for Moderna and 12.6 per million for Pfizer—an almost threefold increase after Moderna shots vs. Pfizer. Comparatively, rates of myocarditis in the general population in 2018, were 2.01 per million in people under age 40 and 2.2 per million in people over age 40.

Rates of myocarditis and pericarditis were higher with the Moderna vaccine in both males and females between ages 18 and 39, with the highest per million rates in males ages 18-29 after a second dose of Moderna.

According to the authors, the findings support recommending certain populations receive certain vaccines to maximize benefits and minimize adverse events.

“Few population-based analyses have been conducted to directly compare the safety of the two mRNA COVID-19 vaccines, which differ in important ways that could impact safety,” said Naveed Janjua, MBBS, DrPH, lead author of the study and an epidemiologist and the executive director of Data and Analytic Services at the British Columbia Centre for Disease Control. “Our findings have implications for strategizing the rollout of mRNA vaccines, which should also consider the self-limiting and mild nature of most myocarditis events, benefits provided by vaccination, higher effectiveness of the Moderna vaccine against infection and hospitalization [found in prior studies], and the obvious increased threat of myocarditis following COVID-19 an infection than with mRNA vaccination.”

Limitations of the research embody that it was observational, which limits the power to find out causality between vaccination and myocarditis or pericarditis. Nevertheless, temporality was ensured within the research design to restrict the time studied between vaccine dose and myocarditis/pericarditis analysis. Additionally, the research relied on hospital and emergency division go to knowledge and should have missed some much less extreme instances.

In a associated editorial remark, Man Witberg, MD, MPH, a heart specialist at Rabin Medical Middle in Petah-Tikva, Israel, wrote the research is reassuring for vaccine security because it offers additional knowledge that myocarditis is a really uncommon antagonistic occasion after each vaccines, and it is a crucial step towards a customized strategy to administering COVID-19 vaccines.

“[The study] ought to assist put to relaxation ‘vaccine hesitancy’ as a result of issues over cardiac antagonistic occasions,” Witberg stated. “That is one in every of only some direct comparisons of the 2 broadly adopted mRNA vaccines, and its outcomes have sensible coverage implications: for a considerable section of the inhabitants affected by heart problems…these knowledge give a powerful argument to preferentially use the BNT162b2 [Pfizer] vaccine over mRNA-1273 [Moderna].”

References: “Comparative Danger of Myocarditis/Pericarditis Following Second Doses of BNT162b2 and mRNA-1273 Coronavirus Vaccines” by Zaeema Naveed, Julia Li, James Wilton, Michelle Spencer, Monika Naus, Héctor A. Velásquez García, Jeffrey C. Kwong, Caren Rose, Michael Otterstatter and Naveed Z. Janjua, 7 November 2022, Journal of the American Faculty of Cardiology.
DOI: 10.1016/j.jacc.2022.08.799

“A Story of two mRNA Vaccines” by Man Witberg and Ilan Richter, 7 November 2022, Journal of the American Faculty of Cardiology.
DOI: 10.1016/j.jacc.2022.09.010

The research was funded by the British Columbia Centre for Illness Management and the Canadian Immunization Analysis Community (CIRN) by way of a grant from the Public Well being Company of Canada and the Canadian Institutes of Well being Analysis. This venture was additionally supported by funding from the Public Well being Company of Canada by way of the Vaccine Surveillance Reference Group and the COVID-19 Immunity Job Drive.