Nov. 26, 2009 (United Press International) -- Federal health officials said they are seeing an increase in serious pneumococcal infections around the United States, a finding described as "worrisome."

"Flu infections can increase the risk of pneumococcal disease -- pneumococcus is a bacteria that commonly affects the lung or sometimes the bloodstream -- in a typical non-pandemic year, most serious pneumococcal infections occur in people age 65 and older, in previous pandemics, there has been an increase in pneumococcal infections in younger people," Dr. Anne Schuchat, director of the Centers for Disease Control and Prevention's National Center for Immunization and Respiratory Diseases, told reporters in a briefing.

"It turns out that in this pandemic, we are seeing an increase in pneumococcal infections in younger persons. We're looking in our active bacterial core surveillance, what we call our ABCs site, and it's in those sites that we have seen this increase in what's called invasive pneumococcal disease."

The CDC looked at the five-year average of how much invasive pneumococcal disease occurs in October. In the Denver metropolitan area -- one of the 10 ABC sites where collaborative investigation is ongoing -- the average for five years is about 20 cases, but there have been 58 serious pneumococcal cases in October, Schuchat said.

"The findings in Denver probably reflect findings that are occurring in other parts of the country where the surveillance hasn't been as intensive," Schuchat said. "There's a vaccine for adults to prevent these serious pneumococcal infections. But only 25 percent of high risk adults under 65 have gotten that vaccine."