There have been 275 reported cases of myocarditis or pericarditis, which are inflammation conditions involving the heart, in people ages 16 to 24 as of May 31, according to a CDC presentation that was prepared for a Food and Drug Administration advisory panel meeting Thursday.
The expected number of cases was between 10 and 102, according to the CDC.
There have been a total of 475 reported cases of myocarditis or pericarditis in people age 30 and younger, according to the CDC. Most patients who were hospitalized, or 81% of them, had full recovery from their systems, the agency said. As of May 31, 15 people remain hospitalized, with three in intensive care.
The majority of cases appear to occur in men and the median time to onset of symptoms is two to three days, according to the CDC.