Bacteria can also result in myocarditis, although it is rare in patients with normal heart function and without a preexisting immunodeficiency. A list of the most relevant infectious organisms is below. Viral: adenovirus, parvovirus B19, coxsackie virus, rubella virus, polio virus, Epstein-Barr virus, hepatitis C virus, and severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2, causing COVID-19)
Protozoan: Trypanosoma cruzi and Toxoplasma gondii (causing Chagas disease and toxoplasmosis, respectively)
Bacterial: Brucella, Corynebacterium diphtheriae, Neisseria gonorrhoeae, Haemophilus influenzae, Actinomyces, Tropheryma whipplei, Vibrio cholerae, Borrelia burgdorferi, Leptospira, Rickettsia, Mycoplasma pneumoniae
Fungal: Aspergillus
Parasitic: Ascaris, Echinococcus granulosus, Paragonimus westermani, Schistosoma, Taenia solium, Trichinella spiralis, visceral larva migrans, Wuchereria bancrofti

Immune conditions
Allergic reaction (e.g., to acetazolamide or amitriptyline)
Kawasaki disease
Autoimmunity (scleroderma, lupus, sarcoidosis, and systemic vasculitides)
Toxic shock syndrome

Drug reactions and toxins
Anthracyclines and other forms of chemotherapy
Antipsychotics including clozapine
Alcohol
Stimulants such as mephedrone and cocaine
Arsenic
Carbon monoxide
Snake venom
Heavy metals (copper or iron)

Vaccination
Myocarditis and pericarditis can be a rare side effect of some vaccines like the smallpox vaccine. Some COVID-19 vaccination doses carry a very small risk (33 per million overall) of causing myocarditis and pericarditis, more so in young men at repeated administration. According to a meta-analysis that does not differentiate between the two mRNA-vaccines BNT162b2 and mRNA-1273, the risk is less than that associated with COVID-19 itself. In adolescent males aged 16 to 17 years the crude reporting rate of myocarditis was 105.9 per million doses of the BNT162b2 vaccine.
Myocarditis, however, has shown to be more common in the male population than in the female. Multiple studies report a 1:1.3-1.7 female-male ratio of prevalence of myocarditis. In young adults, up to 20% of all cases of sudden death are due to myocarditis. Young males specifically have a higher incidence rate than any other population due to their testosterone levels creating a greater inflammatory response that increases the chance of cardiac pathologies. While males tend to have a higher risk of developing myocarditis, females tend to display more severe signs and symptoms, such as ventricular tachycardia and ventricular fibrillation, but do so at an older age. Among patients with HIV, myocarditis is the most common cardiac pathological finding at autopsy, with a prevalence of 50% or more.Myocarditis is the third most common cause of death among young adults with a cumulative incidence rate globally of 1.5 cases per 100,000 persons annually. Myocarditis accounts for approximately 20% of sudden cardiac death in a variety of populations, including adults under the age of 40, young athletes, United States Air Force recruits, and elite Swedish orienteers. With individuals who develop myocarditis, the first year is difficult as a collection of cases have shown there is a 20% mortality rate. Myocarditis in COVID-19
One notable instance of viral myocarditis is the involvement of the SARS-CoV-2 virus; myocarditis from SARS-CoV-2 is associated with a spectrum of severities from asymptomatic to fulminant, and is a complication in approximately 2-7% of COVID-19 cases.