"We were pretty confident when we recommended this vaccine for children it would help them," says Cynthia Whitney, a researcher on both studies. "What was a pretty pleasant surprise was the amount of benefit we've seen in unvaccinated populations."
Steptococcus pneumoniae, also called pneumococcus, is one of the most common causes of bacterial meningitis in children in the United States. It can also cause bacterial pneumonia and deadly bloodstream infections. In its less severe forms it can also cause ear and throat infections. Pneumococcus bacteria can be found colonizing many people's noses and throats without causing infection. Why it suddenly invades the body and causes disease is unknown.
A vaccine against pneumococcal disease has been available for adults and children over 2 years of age since the 1980s, but in 2000 a new vaccine was approved by the FDA for children 2 to 23 months old.
Whitney and her colleagues have been tracking the incidence of the most severe forms of the disease, invasive pneumococcal disease (IPD) defined as meningitis or a bloodstream infection, which can include some cases of pneumonia since the introduction in the vaccine.
"After the first full year we made our first report suggesting the effectiveness of the vaccine. We saw a significant decrease in IPD in target age group," says Whitney. "At that time we weren't sure if it had just been a mild season and the numbers might go back up the next year, or if it was a real downturn due to the
Contact: Jim Sliwa
American Society for Microbiology