Only SIX in 1 million develop rare heart inflammation after second dose of vaccine

Americans are much more likely to develop rare heart inflammation after the second dose of a COVID-19 vaccine compared to the first dose, a new study suggests.

Researchers at Kaiser Permanente Southern California (KPSC) have found that less than one in a million people who receive the first dose of the Pfizer-BioNTech or Moderna vaccine will develop the disease within the next ten days.

In comparison, six in a million people will develop heart inflammation within ten days of the second dose.

But unvaccinated people are still at much higher risk.

The team found that 47.5 out of a million people who had not been vaccinated and had had health checks had the disease.

The results suggest that myocarditis is a rare side effect of the vaccine, and people should feel safe receiving the vaccines.

Myocarditis, the medical name for inflammation of the heart, is a known side effect of viral infections like Covid.

The disease has also been found to be a potential side effect of vaccines, with young men at particularly high risk but at a much lower rate than if they had contracted the virus.

For the study, published Monday in JAMA Internal Medicine, the KPSC team collected data from more than 2.3 million patients in its Southern California health care system.

Researchers looked at participants’ medical records to find out who had received medical attention for myocarditis within ten days of the jab.

Two participants developed myocarditis after receiving the first injection, or 0.8 out of a million people.

By comparison, more than 2.2 million participants returned for screening after the second injection, of which 13 – or 5.8 out of a million – have the disease.

This means that people are seven times more likely to develop the disease after the second dose rather than the first.

Those who developed the disease were evenly split between the participants who received the Pfizer and Moderna injections.

For a control group, the researchers also collected data from 1.5 million unvaccinated people during the study period.

About 47.5 out of a million unvaccinated people developed the disease.

Although those in the control group were not specifically screened because they had already contracted the virus, it is likely that Covid caused the disease in unvaccinated people.

This means that unvaccinated people are eight times more likely to develop myocarditis than people after receiving the vaccines.

Each participant who developed heart inflammation after receiving the vaccine in the study was a male.

This is a known trend, with the Centers for Disease Control and Convention (CDC) warning that young men are particularly vulnerable to myocarditis after receiving the vaccine.

A late July Gallup poll found that fear of side effects – the most common serious side effect of which is myocarditis – is the most cited reason for reluctance to vaccinate.

This KPSC study finds that people who receive the injections are much more likely to experience these negative side effects than those who do not receive the injections.

CDC data also confirms this, with the agency reporting that nearly 1,500 out of a million people who are hospitalized with Covid develop heart inflammation.

Heart inflammation can often lead to fatigue, shortness of breath, and chest pain in patients.

People with inflamed hearts are at a higher risk of heart failure, heart attack, and stroke.

Attempting to exercise vigorously with an inflamed heart could also lead to sudden cardiac arrest or even death.