LINDSEY TANNER - AP Medical Writer

Research in U.S. veterans provides fresh evidence that long COVID-19 can happen even after breakthrough infections following vaccination.

In the study published Wednesday, about 1% who had COVID-19 shots had breakthrough infections. And about one-third of that group showed signs of long COVID.

A separate government report found that 1 in 4 adults age 65 and up developed at least one symptom of long COVID up to a year after an initial infection.

That compares with 1 in 5 younger adults.

Long COVID involves long-term symptoms that can include fatigue, shortness of breath, brain fog and blood clots.