Myocarditis and Pericarditis
Information regarding Myocarditis and Pericarditis with Covid Vaccines
Previous thrombotic event
ATAGI considers that there is no evidence of a risk of thrombotic disease after Pfizer (COMIRNATY) vaccination in people with a history of clotting conditions. ATAGI continues to recommend Pfizer (COMIRNATY) vaccination in such people (ATAGI, 2021d).
This includes those with:
Deep venous thrombosis and/or pulmonary embolism.
People with risk factors for thrombosis (such as use of oral contraceptives or smoking).
People with thrombocytopenia (low platelets that can occur with clotting conditions).
People with known thrombophilic disorders.
People on anticoagulants (e.g. warfarin).
People with a history of cardiovascular disease (such as myocardial infarction or stroke).
People with a confirmed medical history of CVST.
People with a confirmed medical history of heparin induced thrombocytopenia (HIT).
(ATAGI, 2021d)
Myocarditis and pericarditis
The mRNA vaccines Pfizer (COMIRNATY) and Moderna (SPIKEVAX) have been safely given to hundreds of millions of people around the world. These mRNA COVID-19 vaccines have a very rare risk of heart inflammation (myocarditis, pericarditis or combined, myopericarditis). This is more commonly seen in males aged under 30 years after the second dose.
The highest reporting rates of myopericarditis was following the second dose of Pfizer (COMIRNATY) in males 16-17 years old (with 71.5 cases per million doses administered), followed by males aged 12-15 (with 42.6 cases per million). In males aged 18-24, the reporting rate was 37.1 per million following the second dose of Pfizer (COMIRNATY) (ATAGI, 2021b).
In some countries, myocarditis and pericarditis have been reported more commonly after Moderna (SPIKEVAX) than after Pfizer (COMIRNATY). Most people who have had these conditions after their vaccine have recovered fully.
ATAGI states that the benefits of vaccination outweigh this very rare risk and vaccination is still recommended for all eligible age groups. For current information on the frequency and severity of myocarditis and pericarditis following Pfizer (COMIRNATY) or Moderna (SPIKEVAX), please refer to the COVID-19 vaccine safety report published by the Therapeutic Goods Administration (TGA).
Symptoms typically appear within 1-5 days of vaccination and include chest pain, palpitations (irregular heartbeat), syncope (fainting) or shortness of breath. People who experience any of these symptoms after having an mRNA COVID-19 vaccine should seek prompt medical attention.
Pfizer (COMIRNATY) continues to be recommended for all eligible people over 12 years of age who do not have any contraindications to the vaccine.
Most pre-existing cardiac conditions are NOT regarded as contraindications to vaccination.
People with a history of any of the following conditions CAN receive an mRNA vaccine (e.g. Pfizer (COMIRNATY)) but should consult a GP, immunisation specialist, or cardiologist about the best timing of vaccination and whether any additional precautions are recommended:
Recent (i.e. in the past 3 months) or current inflammatory cardiac illness e.g., myocarditis, pericarditis or endocarditis.
Acute rheumatic fever or acute rheumatic heart disease.
Acute decompensated heart failure.
(ATAGI & CSANZ, 2021; ATAGI, 2021b)
Pfizer (COMIRNATY) is recommended for people with a history of most chronic cardiovascular conditions and CAN be given to people in the following groups without any specific precautions:
Prior myocarditis, pericarditis, or endocarditis (i.e. 3 or more months prior to vaccination)
Coronary artery disease
Myocardial infarction
Stable heart failure
Arrhythmias
Prior history of rheumatic heart disease (RHD)
Kawasaki disease
Congenital heart disease
Cardiomyopathy
Cardiac transplant
People with implantable cardiac devices
(ATAGI & CSANZ, 2021; ATAGI, 2021b)
People who develop myocarditis or pericarditis attributed to their first dose of Pfizer (COMIRNATY) are advised to defer further doses of an mRNA COVID-19 vaccine and to discuss this with their treating doctor (ATAGI & CSANZ, 2021).