Myocarditis: symptoms and treatment of rare heart inflammation side effect linked to Pfizer Covid vaccine

Signs of myocarditis and pericarditis include chest pain and shortness of breath

A woman in New Zealand died after receiving her Pfizer Covid-19 vaccine, with an independent vaccine safety monitoring board stating that her death was “probably” due to myocarditis, which is an inflammation of the heart muscle.

However, other medical issues were noted which could have “influenced the outcome following vaccination”.

What happened?

The New Zealand Ministry of Health released a statement following the news of the woman’s death, saying: “The COVID-19 Vaccine Independent Safety Monitoring Board (CV-ISMB) has considered that the woman’s death was due to myocarditis, which is known to be a rare side effect of the Pfizer Covid-19 vaccine.”

The cause of death has not yet been determined, and the case has been referred to the coroner.

V-ISMB Chair Dr John Tait explains that it is important to thoroughly investigate significant and serious adverse events related to vaccination.

“We want to ensure that the outcomes from this investigation are widely available for others to learn from. The findings will be published to increase the scientific knowledge about vaccine-induced myocarditis,” he said.

Dr Tait added: “The Pfizer vaccine is highly effective in protecting against serious illness and death from COVID-19, and we remain confident about using it in New Zealand.”

What is myocarditis?

The Myocarditis Foundation explains that, in simple terms, “myocarditis is a disease that causes inflammation of the heart muscle”.

It continues: “This inflammation enlarges and weakens the heart, creates scar tissue and forces it to work harder to circulate blood and oxygen throughout the body.”

While heart conditions are generally associated more with the elderly, myocarditis can actually affect anyone, regardless of their age.

In fact, according to the Myocarditis Foundation, it most often affects “otherwise healthy, young, athletic types with the high-risk population being those of ages from puberty through their early 30s, affecting males twice as often as females”.

Viral infections are the leading cause of myocarditis, with inflammation occurring during the course of the infection, putting stress on the heart that continues after the infection is cleared up.

What are the symptoms of myocarditis?

The Myocarditis Foundation says that one of the biggest challenges regarding diagnosing myocarditis is that it has a lack of specific symptoms.

“In many cases, individuals experience no symptoms at all,” the foundation says.

Common symptoms can include, but are not limited to:

  • Shortness of breath, especially after exercising or when lying down 
  • Fatigue
  • Heart palpitations
  • Chest pain or pressure
  • Lightheadedness
  • Swelling in the hands, legs, ankles and feet
  • Sudden loss of consciousness

If you or someone you know has any of these symptoms, it’s important to contact a doctor straight away.

How is it diagnosed?

Common tests for myocarditis includes:

  • An electrocardiogram, which uses electrodes taped to your skin to monitor the electrical activity of your heart 
  • A chest x-ray
  • A echocardiogram, which uses sound waves, that are too high pitched to actually be heard, to make an image of your heart, or analyse your blood flow 
  • Less frequently an MRI scan may be used to diagnose myocarditis 
  • Occasionally, a heart biopsy is needed to confirm the diagnosis 

How is it treated?

Treatment for myocarditis can vary from person to person, but can include methods such as medication, including anti-inflammatory medications and antibiotics.

The British Heart Foundation (BHF) says: “In long term cases myocarditis can affect your heart muscle and tissue, meaning you could develop heart failure. If the damage is severe you may need a heart transplant.”

What is pericarditis?

Pericarditis has also been linked to the Pfizer and Moderna Covid-19 vaccines as well.

The BHF says: “Pericarditis is inflammation of the pericardium, the protective sac that surrounds your heart. The pericardium has two layers (inner and outer) and can become inflamed if blood or fluid leaks between these two layers.”

Pericarditis can be caused by a virus or bacterial infection, and the symptoms of pericarditis include:

  • Chest pain that feels like a stabbing sensation
  • Pain in the neck that can spread across the shoulders and/or arms
  • Fever
  • Nausea
  • Lightheadedness
  • Sudden shortness of breath

Treatment for pericarditis depends on the individual case, but common methods include anti-inflammatory medications like colchicine, painkillers and in some cases a pericardial window, which is a surgery that drains the sac surrounding the heart.

Is the Pfizer vaccine safe?

In July, the Medicine and Healthcare products Regulatory Agency (MHRA) came to the conclusion that, following a “thorough review” of data in both the UK and internationally, there may be “an extremely rare risk” of inflammatory heart conditions following jabs of the Pfizer and Moderna vaccines.

The MHRA stressed that the benefits of the vaccines “greatly outweigh” any possible risks.

The conclusion from the MHRA came after the European Medicines Agency (EMA) said that myocarditis and pericarditis could occur “in very rare cases” for those who received either vaccine.

Dr June Raine, CEO of the MHRA said: “The MHRA has conducted a thorough review of the data, both in UK and international sources, and has identified that there may be an extremely rare risk of myocarditis and pericarditis following vaccination with the Moderna and Pfizer Covid-19 vaccines.

“Reports of suspected myocarditis and pericarditis post-vaccination with Pfizer/BioNTech and Moderna typically describe mild symptoms and recovery, following usual treatment and rest.

“The benefits of these vaccines in protecting against hospitalisation and death from Covid-19 greatly outweigh any potential risks, and people are encouraged to continue to come forward for their first and second vaccination when invited to do so.

In New Zealand alone, more than 3.3 million doses of the Pfizer vaccine have been administered, and this is the first case in the country where a death in the days following the vaccination has been linked to the vaccine.

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