Most Young People Recover Quickly From Myocarditis Side Effect of COVID-19 Vaccine

New research shows young people are recovering quickly from the rare myocarditis side effect of the COVID-19 vaccine.

Most adolescents and young adults with suspected myocarditis following a COVID-19 vaccination experience mild symptoms and rapid clinical recovery, although many had evidence of ongoing heart inflammation, according to a new study published today. The study authors said rapid ventricular rhythms and the need for drugs to raise blood pressure were unusual; no patients died or required mechanical circulatory support as a result of the condition. While cases of myocarditis following COVID-19 vaccinations remain rare, more research is needed to understand whether there are long-term cardiac effects of COVID-19 vaccine-associated myocarditis.

Most young people under the age of 21 who developed suspected COVID-19 vaccine-related heart muscle inflammation, known as myocarditis, had mild symptoms that quickly improved, according to new research published today (Dec. 6, 2021) in the American Heart Association’s flagship journal Circulation. .

Myocarditis is a rare but serious condition that causes inflammation of the heart muscle. It can weaken the heart and affect the heart’s electrical system, keeping the heart pumping regularly. It is usually the result of an infection and/or inflammation caused by a virus.

“In June of this year, the U.S. Centers for Disease Control and Prevention (CDC) Advisory Committee on Immunization Practices reported a likely association between mRNA COVID-19 vaccination and myocarditis, particularly in people under the age of 39. However, research continues to find COVID-19. -19 vaccine-related cases of myocarditis are rare and usually mild,” said Donald. M. Lloyd-Jones, MD, Sc.M., FAHA, president of the American Heart Association, who was not involved in the study. “Overwhelmingly, data continues to indicate that the benefits of COVID-19 vaccination — 91% effective in preventing complications of severe COVID-19 infection, including hospitalization and death — far outweigh the very rare risks of adverse events, including myocarditis. “

“The highest rates of myocarditis following COVID-19 vaccination have been reported in adolescent and young adult males. Past research shows that this rare side effect is related to some other vaccines, especially the smallpox vaccine,” said senior author of the new study Jane W. Newburger, MD, MPH, FAHA, associate chair of Academic Affairs in the Department of Cardiology at Boston Children’s Hospital, the Commonwealth Professor of Pediatrics at Harvard Medical School and a member of the American Heart Association’s Council on Lifelong Congenital Heart Disease and Heart Health in the Young. Short-term results are limited, we wanted to investigate a large group of suspected cases of this heart condition associated with the COVID-19 vaccine in teens and adults under the age of 21. North America.”

Using data from 26 pediatric medical centers in the United States and Canada, researchers reviewed the medical records of patients younger than 21 who showed symptoms, lab results, or imaging findings suggestive of myocarditis within one month of receiving a COVID-19 infection. vaccination, by July 4, 2021. Cases of suspected vaccine-associated myocarditis were categorized as “probable” or “confirmed” using CDC definitions.

Of the 139 teens and young adults, ranging in age from 12 to 20, researchers identified and evaluated:

Most patients were Caucasian (66.2%), nine of 10 (90.6%) were male, and the median age was 15.8 years. Nearly all cases (97.8%) followed an mRNA vaccine and 91.4% occurred after the second vaccine dose. Symptoms started a median of 2 days after vaccine administration. Chest pain was the most common symptom (99.3%); fever and dyspnea each occurred in 30.9% and 27.3% of patients, respectively. About one in five patients (18.7%) was admitted to the intensive care unit, but there were no deaths. Most patients were hospitalized for two or three days. More than three quarters (77.3%) of patients who received a cardiac MRI showed signs of inflammation or injury to the heart muscle. Nearly 18.7% had at least mildly reduced left ventricular function (squeezing the heart) at presentation, but heart function returned to normal in all who returned for follow-up.

“These data suggest that most cases of suspected COVID-19 vaccine-related myocarditis in people under the age of 21 are mild and resolve quickly,” said the study’s lead author, Dongngan T. Truong, MD, an associate professor of pediatrics in the department. cardiology at the University of Utah and a pediatric cardiologist at Intermountain Primary Children’s Hospital in Salt Lake City. “We were really happy to see that kind of recovery. However, we await further studies to better understand the long-term outcomes of patients who have had COVID-19 vaccination-related myocarditis. We also need to study the risk factors and mechanisms for this rare complication.”

Researchers say future studies should follow patients who have suffered longer-term vaccine-associated myocarditis, as this study only examined the immediate course of patients and lacks follow-up data. In addition, there are a number of important limitations that must be taken into account. The study design did not allow scientists to estimate the percentage of those who received the vaccine who developed this rare complication, nor did it allow a risk-benefit study. The patients included in this study were also evaluated in academic medical centers and may have been more severely ill than other community cases.

“It is important for healthcare professionals and the public to have information about early signs, symptoms and the time course of recovery from myocarditis, especially as these vaccines are becoming more widely available for children,” Truong said. “Studies to determine long-term outcomes in those who have had myocarditis after COVID-19 vaccination are also planned.”

Researchers recommend that healthcare professionals consider myocarditis in individuals with chest pain after receiving a COVID-19 vaccine, especially in boys and young men in the first week after the second vaccination.

“This study supports what we’ve seen — people who are identified and treated early and appropriately for COVID-19 vaccine-related myocarditis typically experience mild cases and short recovery times,” Lloyd-Jones said. “These findings also support the American Heart Association’s position that COVID-19 vaccines are safe, highly effective and fundamental to saving lives, protecting our families and communities from COVID-19 and ending the pandemic. Have your child vaccinated as soon as possible.”

Reference: December 6, 2021, Edition.
DOI: 10.1161/CIRCULATIONAHA.121.056583

The names of the study authors and their disclosures are included in the manuscript.

This research received no external funding.