Both Pfizer and Moderna are launching clinical trials to track health issues — if any — in the years following a diagnosis of vaccine-associated heart problems in teens and young adults.
In October 2021, Da’Vion Miller was found unconscious in the bathroom of his home in Detroit a week after receiving his first dose of Pfizer's Covid vaccine.
He had known something was wrong: Then 22, he had started experiencing chest pain two days after getting vaccinated, followed by fatigue, shortness of breath and dizziness.
Miller was rushed to Henry Ford West Bloomfield Hospital, where he was diagnosed with myocarditis, an inflammation of the heart muscle, and pericarditis, an inflammation of the outer lining of the heart. His doctor advised him not to receive a second dose of either the Pfizer or the Moderna vaccines.
“I was like, that’s crazy,” Miller said, noting that he knows the heart inflammation condition following vaccination is extremely rare.
Miller is one of a very small group of people in the United States who have experienced myocarditis following vaccination with the Pfizer-BioNTech or the Moderna Covid vaccines based on mRNA technology.
Myocarditis is a condition that has long been linked to a number of viral infections, including influenza, coxsackieviruses, as well as Covid. It has also been observed as an infrequent but worrisome side effect of the mRNA Covid vaccines.