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Although rare, recipients of Moderna Covid vaccine have higher risk of heart inflammation than Pfizer


Moderna’s two-dose Covid-19 vaccine is associated with a higher risk of heart inflammation than Pfizer’s, but the benefits of both companies’ injections outweigh the risks, a panel of outside Centers experts say. for Disease Control and Prevention.

The CDC’s Advisory Committee on Immunization Practices met on Friday to discuss the risks of developing myocarditis after receiving vaccines from Moderna or Pfizer.

According to the National Heart, Lung and Blood Institute, myocarditis is inflammation of the heart muscle that can lead to serious health problems. Although myocarditis is the most common after viral infection, the CDC has found a link between heart inflammation and vaccination with vaccines from Moderna and Pfizer.

The risk of myocarditis after Covid vaccination is highest in adolescents and young men after the second dose of mRNA vaccines, the technology used by both Moderna and Pfizer. Symptoms develop a few days after vaccination, including chest pain, shortness of breath, heart palpitations and fatigue.

Although rare, vaccines from Pfizer and Moderna have both been linked to a risk of myocarditis. However, the risk was higher after the second dose of Moderna’s vaccine in people aged 18 to 39, according to the CDC’s Safety Monitoring Program, which collects data from nine healthcare organizations in eight. States.

For every million second doses given, Moderna vaccinees had 10.7 more cases of myocarditis and pericarditis than people who received Pfizer, according to the study. The difference was even greater in men, who experienced 21.9 cases of excess myocarditis and pericarditis with Moderna’s second vaccine, while women had 1.6 additional cases.

However, there was no difference in the symptoms experienced by people who received the vaccines from either company. Most patients were hospitalized for a single day and no one was admitted to intensive care, according to the study.

Public health authorities in Ontario, Canada, found that the rate of myocarditis was five times higher in men aged 18 to 24 after the second dose of Moderna’s vaccine than in Pfizer. The rate of myocarditis was also higher in people in the same age group who received Pfizer as the first dose and Moderna as the second than in people who received two injections of Pfizer.

Dr Sara Oliver, a CDC official, said more cases of myocarditis would be expected after Moderna’s vaccine, but the company’s vaccines would also prevent more Covid hospitalizations than Pfizer’s vaccine. “The benefits still for mRNA vaccines far outweigh the potential risk,” Oliver said.

Canada, the UK and several other countries have recommended Pfizer’s vaccine over Moderna’s in high-risk age groups. Dr. Pablo Sanchez, professor of pediatrics at Ohio State University, said CDC vaccine experts should consider making a similar recommendation.

“We may at least in the higher risk groups, this young man, that we should perhaps recommend a preference of Pfizer over Moderna,” Sanchez told the committee.

Researchers are still studying what triggers myocarditis after vaccination against Covid. Canadian public health authorities also found that the rate of myocarditis was higher for Moderna and Pfizer vaccines when the interval between the first and second dose was less than 30 days.

CDC vaccine experts are considering a longer interval of 8 weeks between the first and second doses of the two companies’ vaccines to address the risk of myocarditis. Moderna’s vaccine is fully approved for adults 18 years and older. Pfizer’s vaccine is fully approved for ages 16 and older and authorized for emergency use in children ages 5 to 15.

The overwhelming majority of people who had myocarditis after Covid vaccination made a full recovery and most reported no impact on their quality of life, according to a CDC survey of cardiologists and other healthcare providers health.

The survey found that 81% of their patients who developed post-vaccination myocarditis made a full or probable recovery within 37 weeks of their diagnosis. Another 15% had improved, while 1% had not improved.

Most patients, 83%, had restrictions on their physical activity after their diagnosis of myocarditis. However, 39% still had restrictions at the time of the survey. Doctors recommend that people who develop myocarditis avoid vigorous physical activity for a few months to ensure their heart recovers fully.

According to the data, there were no known post-vaccination myocarditis deaths in the group.

According to the Department of Health and Human Services, people are at a much higher risk of developing myocarditis from Covid infection than vaccines. The risk of myocarditis from Covid is 100 times greater than developing the disease after Covid vaccination, according to a recent article in Nature Reviews Cardiology.

“There is a bit of danger in focusing on the vaccine and myocarditis when the elephant in the room is really a real disease, a real COVID-19 infection and potentially devastating, even deadly myocarditis,” said Dr. Camille Kotton, expert in infectious diseases. disease and people with weakened immune systems, at Massachusetts General Hospital in Boston.

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