Coronavirus mRNA vaccines and heart inflammation: What do we know so far

Ever since reports of some COVID mRNA vaccines fueling a rise in heart inflammation condition, or myocarditis first emerged in Israel in early June, there have been pressing concerns and controversies surrounding the use of novel mRNA vaccines. The rising reports have now forced clinical bodies, including FDA to issue an advisory on the usage of the vaccines in the younger population.

mRNA COVID vaccines, such as the ones being developed by Pfizer-BioNTech, Moderna Inc. are not just some of the most sought-after vaccines worldwide, but also highly talked about for their benefits and specific ability to target a pathogen once administered.

READ MORE: When can we expect Pfizer, Moderna mRNA vaccines in India?

With Pfizer and Moderna expected to be made available in India soon, the claims of apparent heart ailments may also give rise to skepticism and fears surrounding the use of these vaccines.

We explain the link, and the risks entailing their use:

Amidst increasing controversies surrounding the rise of blood clots with the Oxford-Astrazeneca vaccine and Johnson and Johnson’s Jannsen vaccine, reports of the Pfizer shot putting younger men at a heightened risk of myocarditis were witnessed in Israel, following which, the country's health ministry launched investigations.

READ MORE: Are side-effects worse after the second COVID vaccine jab?

Reports classified the condition as a 'rare' side-effect linked to the vaccine, concluding that it affected 1 in 3000 men aged between 16-24. Similar clinical investigations were launched by the US CDC and European Medical Agency, where cases of myocarditis post-vaccination were observed.

Researchers also observed that symptoms of myocarditis and pericarditis, after vaccination were mostly reported in countries depending on mRNA vaccine, a week after beneficiaries were given their second vaccine dose, and mostly recorded in men younger than 30.

Myocarditis refers to the condition which is caused when the middle layer of the heart gets inflamed. The inflammation is usually caused by a severe infection, or viral damage that can weaken the heart's electrical system, lead to heart failure, abnormal (erratic) heartbeat or arrhythmias, and in some cases, even sudden death.

Similar to myocarditis, pericarditis is the inflammation of the heart's outer tissue (pericardium), which, when infected, could cause possible problems like disrupted oxygenated blood flow, pain, weakening of muscles and heart walls.

While most cases of myocarditis are tied to severe infections, it can also be sometimes caused when our body reacts to a certain drug, or be a part of general inflammation launched by the body, which may be likely a reason for it to be caused by the mRNA vaccines.

Myocarditis tends to weaken heart muscles, which further disrupts the flow of oxygen in the body and may cause problems like a stroke or a heart attack. However, the most common ways a myocarditis infection shows up is with symptoms like chest pain, shortness of breath, sweating, pain around the shoulder.

Having a rapid, fast-beating, fluttering, or heavy heart rate could also be signs of myocarditis inflammation.

Some acute symptoms of the infection could also be felt in the form of dizziness, fatigue, palpitations, swelling in extremities.

Patients who have received the second dose of the mRNA vaccine (or even the first dose) have been asked to be on the lookout for these possible signs and symptoms, and get help at once.

Despite the experimental nature of COVID-19 vaccines clouding skepticism, experts say that myocarditis events post-vaccination, even though rare, aren't exactly new.

For example, there have been anecdotal reports suggesting the possible development of myocarditis post flu vaccination.

Apart from that, the other COVID-19 vaccines which have been approved for use haven't yet been found to carry such potential effects. Blood clotting incidents, vasovagal reactions, and a drop in blood pressure levels have been reported, in fewer numbers.

While myocarditis infections post COVID vaccination have increasingly emerged, investigations and researches have still dubbed the infection to be a 'rare' possibility, which may not impact everyone. More so, investigators have asserted that the incidental risk amongst the actual population who have received mRNA vaccine doses is quite rare, so shouldn’t be worried about, unless and until a proper scientific risk is established.

Scientists are yet to find a complete link between adverse reactions and vaccination. However, from what has been observed, most of the issues seem to be rare, mostly non serious. A report also found that most patients who did experience heart inflammation with the vaccine spent no more than 4 days in the hospital, and nearly 95% of cases were deemed mild. Therefore, it cannot be yet certified as a serious, potentially life-threatening issue caused by the vaccine.

Myocarditis post-vaccination can be concerning, but from what several clinical studies have right now pointed out, the incidental rate of myocardial infarction post an actual COVID infection is much riskier and can have life-altering consequences as well. The precedence of people suffering from vital organ damage, and post-COVID-heart problems during the recent months has been a major cause of concern to doctors, who now advise COVID recovered patients to get their heart checked up and be on the lookout for possible complications.

While the adverse reactions have also been subjected to further review, experts also say that the incidents do not impact the vaccine's efficacy rates, and definitely outweigh the risk of catching the infection.