Myocarditis and Pericarditis in Boys after COVID-19 Vaccine Jabs is Very Rare: Tutorial for Parents

Recently, we discussed how COVID-19 can strike children, including those without risk factors and much more so in those with risk factors, such as obesity and conditions that weaken the immune system, or that involve treatments that weaken the immune system. We noted that, usually, when children do develop symptoms, they are mild, cold-like symptoms. However, we also said that the percentage of infected children who develop severe disease is not zero. This led us to discuss a rare complication, called multi-system inflammatory syndrome in children (MISC, or MIS-C). This can develop subsequent to —typically 2 to 6 weeks after—  an infection with SARS-CoV2 (the virus that causes COVID-19), whether or not the child ever suffered any COVID-19 symptoms. MIS-C involves inflammation of multiple organs, which usually includes the heart, but heart inflammation also can develop as its own complication during COVID-19, plus you may also have heard that it has been reported following jabs of an COVID-19 mRNA vaccine. These vaccines include the Pfizer-BioNTech vaccine, which as of mid-February 2022 (when I am writing this) is approved for, and available to people ages 5 years and up. They also include the Moderna vaccine, which is for ages 18 and up. Such heart inflammation is very rare, but it came up during an interview of a physician-scientist, Dr. Robert Malone, who discussed his objections to COVID-19 vaccines for more than 3 hours on the popular podcast, The Joe Rogan Experience, this past December. Although it’s not much of an issue for women whether pregnant or not, the heart complications, while extremely rare, do affect younger adults (those under age 40) much more than older people. They also tend to affect males, so it might be a concern for you, if you have a teenage boy, or even an adolescent boy. During his interview with Joe Rogan, however, Malone presented a distorted account of the heart inflammation issue, especially with respect to how often it occurs and the severity, so let’s unpack that.

First of all, let’s define the heart inflammation conditions. These consist of myocarditis— meaning inflammation of the myocardium, the heart muscle itself, the thickest layer of the heart, the layer that does the actual pumping— and pericarditis, inflammation of the pericardium, a sac-like membrane that surrounds the heart.

Not only during his Rogan interview, but in numerous talks and interviews, Malone makes all sorts of insinuations that spike glycoprotein —the protein for which the COVID-19 mRNA vaccines carry a recipe for your cells to manufacture— causing damage to organs. However, only a tiny amount of body cells actually receive the vaccine, only a tiny, finite amount of spike protein is ever produced, and the spike protein that is produced ends up attached to the outside of cells that make it. Furthermore, most of the cases of myocarditis and pericarditis that occur following an mRNA vaccine jab (typically around 4 days after the jab) occur after the second jab. After that second jab into an arm, you make the same, minute amount of spike protein that you make after the first jab. This implies that the cause of myocarditis and pericarditis is an immune-mediated effect. It’s related to the immune system responding more strongly after the second jab than the first, because the immune system has already been primed from that earlier jab. The same is true in someone receiving a jab who already has suffered COVID-19; the chance of developing myocarditis is elevated, because it is an immune response. So the spike protein itself is not going to the heart and causing inflammation there. Rather, it is inflammation happening throughout the body, related only indirectly to the spike protein, meaning due to the immune response itself.

But very importantly, the occurrence of myocarditis and pericarditis after the second vaccine jab is very rare, even in boys and young men. To illustrate how Malone has been misleading about the myocarditis and pericarditis risk, let’s consider what he did during his Rogan interview, when he referred to a study conducted in Hong Kong. The study reported myocarditis and pericarditis occurring after mRNA vaccination, in children ages 12-17, mostly boys. Malone said that the study reported the complications at a rate of one case per 2,700 vaccinations, which actually is correct, according to the scientific paper by the researchers in Hong Kong. However, Malone told Rogan that the cases were serious cases, because the children in the Hong Kong study with myocarditis/pericarditis were hospitalized. Malone’s reasoning was based, not on the particulars of each case, such as the results of tests on the children’s hearts and blood. Instead, his reasoning was based just on the fact that the boys had been admitted to the hospital, rather than being sent home to rest. You see, we know from other scientific papers that myocarditis and pericarditis following mRNA jabs is rare (usually the scientific papers report a lower incidence than the 1 in 2,700 rate of the Hong Kong paper) and also usually mild, requiring just rest and anti-inflammatory medicine, or even no medicine at all. But the Hong Kong study itself shows that the children with myocarditis and pericarditis also had mild cases, every one of them. They recovered easily, but they were hospitalized, because it was a scientific study looking specifically for such adverse effects, so the researchers running the study needed to run some very specialized tests that could be done only in the hospital.

Not only are these heart complications very rare and usually mild when they do occur, but you may have noticed that the concern begins at the age of 12. It has not been an issue in the 11 year-old boys. Part of this may have to do with male hormones, since actually some other studies, which divide up the ages of boys differently, show a higher incidence of myocarditis in boys ages 16 and up compared with the 12-15 year age group. Possibly more important is the fact that children ages 11 and lower receive just one third the vaccine dose compared with children ages 12 and up, who receive the adult dose of the Pfizer-BioNTech vaccine. Now, if you are a parent of of a still younger child, age 6 months to four years and concerned about heart effects of Pfizer-BioNTech that’d being tested and gearing up for emergency use authorization, keep in mind that the dosage of that baby vaccine is even lower than the dose that the 5-11 year olds receive. The vaccine that’s coming for 6 month to 4 year olds is one tenth the dosage of the adult vaccine and there has not been a signal related to heart inflammation that has been an issue with the older boys, however rare.

David Warmflash
Dr. David Warmflash is a science communicator and physician with a research background in astrobiology and space medicine. He has completed research fellowships at NASA Johnson Space Center, the University of Pennsylvania, and Brandeis University. Since 2002, he has been collaborating with The Planetary Society on experiments helping us to understand the effects of deep space radiation on life forms, and since 2011 has worked nearly full time in medical writing and science journalism. His focus area includes the emergence of new biotechnologies and their impact on biomedicine, public health, and society.

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