No, or rarely.

Cardiomyopathy is a long-term disease of the heart muscle. The established vaccine-linked heart problem is myocarditis, which is acute inflammation. Myocarditis of any cause can occasionally lead to cardiomyopathy, so a very small link is conceivable. But there is no good evidence that vaccination causes cardiomyopathy as a distinct outcome, apart from isolated case reports. Because this has not been well studied, the answer is 'not shown' rather than ruled out. Long-term follow-up of people who had myocarditis after vaccination is ongoing.

• Myocarditis and pericarditis after mRNA vaccines are an established but very rare effect, mostly in males aged about 12–30 after dose 2.
• Most vaccine-related myocarditis cases are mild and recover. Follow-up studies show some people keep minor MRI changes, but long-term outcomes are still being studied.
• Large population studies have not shown a clear rise in cardiomyopathy after vaccination.
• Myocarditis from COVID-19 infection itself is more common and often more severe than after vaccination.

The evidence supports an exceptional pathway from vaccination to myocarditis and then heart-muscle dysfunction, rather than a general tendency for COVID vaccines to cause cardiomyopathy. Evidence specifically for cardiomyopathy is much more limited than the established myocarditis evidence: it includes individual clinical reports and a small number of follow-up events. The extremely-rare classification is therefore an inference, not a directly measured incidence, and developing cardiomyopathy after vaccination alone does not establish its cause.

• Pfizer and Moderna COVID-19 vaccines can cause myocarditis; that causal relationship is established.
• Myocarditis and cardiomyopathy are different diagnoses, although myocarditis can lead to dilated cardiomyopathy.
• A published case documented biopsy-confirmed inflammatory dilated cardiomyopathy following Moderna vaccination, with other investigated causes excluded.
• For 2023–2024 mRNA formulations, myocarditis or pericarditis occurred within seven days at approximately 8 cases per million doses overall among recipients aged 6 months–64 years, and 27 per million in males aged 12–24; these are not cardiomyopathy rates.
• In the follow-up cohort, dilated cardiomyopathy occurred in 1.0% of post-vaccination myocarditis patients versus 3.7% of patients with viral myocarditis.

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Cardiomyopathy refers to a disease of the heart muscle that makes it harder to pump blood, often leading to heart failure. Extensive safety monitoring and population-based cohort studies encompassing hundreds of millions of vaccinated individuals worldwide have found no increased risk of developing cardiomyopathy following COVID-19 vaccination. The vaccines, specifically mRNA vaccines, do carry a very rare risk of a related but distinct condition: acute myocarditis, or temporary inflammation of the heart muscle. Across the general vaccinated population, myocarditis occurs in roughly 1 to 2 individuals per 100,000. While the risk peaks in young males aged 12 to 24 at roughly 1 in 10,000 to 1 in 20,000, these cases are overwhelmingly mild and resolve promptly with supportive medical treatment. By comparison, COVID-19 infection itself presents a much higher risk of myocarditis, myocardial injury, and subsequent cardiomyopathy.

• Large global surveillance databases tracking hundreds of millions of doses show no increased incidence of chronic cardiomyopathy following COVID-19 vaccination.
• mRNA COVID-19 vaccines carry a very rare risk of acute myocarditis and pericarditis, most frequently in males aged 12 to 29 after a second dose.
• The vast majority of vaccine-associated myocarditis cases are mild, transient, and resolve quickly with conservative care.
• Infection with the SARS-CoV-2 virus carries a substantially higher risk of myocarditis, cardiomyopathy, and heart failure than vaccination.

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The claim as asked is about cardiomyopathy, a disease of the heart muscle. The well-established vaccine safety signal is for myocarditis and pericarditis, which are classified as separate conditions even though myocarditis can occasionally lead to myocardial injury or, rarely, dilated cardiomyopathy. Because the question names cardiomyopathy specifically, the honest answer is that the vaccine has not been shown to cause it; the neighbouring finding that the evidence does support - rare myocarditis and pericarditis, concentrated in young males after a second mRNA dose and usually mild - is given with its size so the answer is not read as a claim that the vaccines carry no heart-related risk at all.

• Multiple large population studies link mRNA COVID-19 vaccines to myocarditis and pericarditis, with the highest rates in males aged roughly 12-29 after the second dose, typically within a week of vaccination.
• Reported rates in the highest-risk group are on the order of 1 in 10,000 to 1 in 30,000 doses; rates are lower after booster doses and much lower across all ages and both sexes combined.
• Most post-vaccination myocarditis cases have been mild, with symptoms resolving on rest and standard treatment; follow-up studies show low rates of serious complications.
• Cardiomyopathy as a separate diagnosis after COVID-19 vaccination has appeared in case reports and some case series, but no consistent epidemiological signal has established the vaccine as a cause of cardiomyopathy itself.
• Studies comparing the two find a higher risk of myocarditis after COVID-19 infection than after vaccination (for example, roughly 16 vs 2-3 per 100,000 in comparable groups, and higher still in hospitalised COVID-19 patients).

The scientific evidence shows that COVID-19 mRNA vaccines are associated with a rare risk of myocarditis, particularly in adolescent and young adult males, usually after the second dose. The incidence is low, with studies estimating about 12.6 cases per million second doses in this group. Most cases are mild and resolve with minimal or no long-term damage, though a small subset may experience persistent cardiac dysfunction. Cardiomyopathy, however, is a more severe and chronic condition involving the heart muscle's ability to pump blood effectively. There is no strong evidence that COVID-19 vaccines directly cause cardiomyopathy. The confusion may arise because myocarditis, if severe or recurrent, can sometimes lead to cardiomyopathy, but this is not a common outcome of vaccine-associated myocarditis. The evidence is strong and consistent across multiple large-scale studies and systematic reviews, indicating that while myocarditis is a rare side effect, cardiomyopathy is not directly linked to COVID-19 vaccination.

• COVID-19 mRNA vaccines are linked to a small increase in myocarditis cases, mainly in young males after the second dose.
• The risk of myocarditis after vaccination is rare, estimated at about 12.6 cases per million second doses in young males.
• Most cases of vaccine-associated myocarditis are mild and resolve with minimal or no long-term damage.
• There is no evidence that COVID-19 vaccines cause cardiomyopathy, but myocarditis can sometimes result in temporary cardiac dysfunction.
• The risk of cardiac complications from COVID-19 infection is much higher than from vaccination.

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