A growing body of worldwide evidence has found an increased risk of heart problems in youth following COVID-19 vaccination.
In December, researchers in Australia reported that most people (54.8%) who suffered myocarditis and myopericarditis after vaccination still suffered persistent symptoms six months later.
“At all follow-up time points, females were significantly more likely to have ongoing symptoms,” researchers wrote.
In the study, 51.9% of male respondents reported their symptoms had resolved, compared to just 22.6% of female respondents.
Myocarditis refers to the inflammation of a heart muscle called the myocardium, while myopericarditis is a condition in which the myocardium and the pericardium — the heart’s protective sac — are inflamed. The body releases the protein troponin as a result.
“Male patients were more likely to report earlier and more complete symptom recovery, despite significantly higher average initial peak troponin,” the study observed.
“Females were also more likely to continue medication and have ongoing exercise restrictions,” it said. “However, males were significantly more likely to have higher initial peak troponin results and abnormal initial cardiac imaging investigations.”
The survey responses were received between Feb. 22, 2021 and Sept. 30, 2022.
Researchers acknowledged a previous study that suggested most people with myocarditis after COVID-19 vaccination recover quickly. A study by the Centres for Disease Control published in Lancet September 21, 2022 showed that 81% of such patients were deemed to have recovered within 90 days after being diagnosed. Yet, that may not mean all damage has been healed.
“Even though initial symptoms may resolve quickly, underlying changes on imaging investigations such as [edema], non-ischaemic late gadolinium enhancement (LGE) and hypokinesia have been noted in some COVID-19 vaccine myocarditis cases,” the CDC authors noted.
“This may be a marker of significant myocardial injury, necrosis, scarring, or fibrosis and may result in long term morbidity.”
Edema is a build-up of fluids in the body, resulting in swollen tissues. LGE is a technique used in a cardiac MRI to assess myocardial scars. Hypokinesia is a kind of movement disorder.
Many studies have shown myocarditis among individuals who were vaccinated against COVID-19. A July 25 study from Denmark looked at more than 2.2 million adults aged 50 years and above who received three COVID-19 vaccine doses. After a fourth dose, researchers observed nine cases of myocarditis and 22 cases of pericarditis within 28 days of vaccination.
An August study in Acta Paediatrica looked at 52,720 US pediatric reports of adverse events after COVID-19 vaccination. It found 567 cases of myocarditis from Pfizer vaccine recipients.
“Our study showed that most of the cases of myocarditis occurred in males,” the authors wrote. A previous study conducted by Oster et al., similarly showed that 82% of the cases involved males.
“In addition, comparing our findings with those of Oster et al., we can reiterate that the risk of myocarditis after receiving mRNA-based COVID-19 vaccines was highest after the second vaccination dose in adolescent males.”
A German study published on November 27 looked at 25 people who died “unexpectedly” at their homes within 20 days of receiving a COVID-19 vaccine. Five had died with myocarditis, each of them having taken a Pfizer or Moderna vaccine within seven days of their deaths. Three of the cases identified the vaccine as the likely cause of death, whereas the other two found the vaccine a possible cause.
In September, the Florida Department of Health warned residents of “safety and efficacy concerns” in its guidance on COVID-19 boosters.
“The mRNA COVID-19 vaccines present a risk of subclinical and clinical myocarditis and other cardiovascular conditions among otherwise healthy individuals,” the guidance said.
A peer-reviewed Japanese study published in the Cureus journal on December 7 found 70% of people who died in Japan after receiving a Pfizer COVID-19 vaccine did so within the first ten days following the jab, usually of heart issues.
By contrast, a recently-released study by Spanish researchers found no signs of heart inflammation among vaccinated children. However, only 23 children in their study had received a COVID-19 vaccine.
