The study appears in the September issue of the journal "Pediatrics."

The pneumococcal conjugate vaccine is well known to control bacterial meningitis and bacteremia -- a bacterial infection in the blood system -- but doctors needed good evidence that it helped control other illnesses.

Ear infections (otitis media) and pneumonia are common infections in children; there are more than seven million cases of ear infection and more than one half million cases of pneumonia each year.

Poehling and colleagues studied data from Tennessee's Medicaid records and from three commercial insurance companies in upstate New York. They found that after routine vaccination with the pneumococcal conjugate vaccine began children in Tennessee younger than 2 years old had 7 percent fewer cases of otitis media in Tennessee; 20 percent of these children New York got ear infections.

Likewise, there were 17 percent fewer cases of pneumonia in Tennessee and 30 percent fewer cases in New York. These translate to about 10 fewer doctor visits, per 100 children, in Tennessee for ear infections and 40 fewer in New York; there were two fewer visits, per 100, for pneumonia in Tennessee and four fewer in New York.

"The cost control implications -- reducing emergency department and outpatient visits -- are also very important," Poehling said.

The study provides "the first data that demonstrate a decline in all pneumococcal-related diseases, not just invasive disease, in children aged younger than 2 years since the introduction of pneumococcal conjugate vaccine in the United States," Poehling and colleagues wrote in the journal.

Vanderbilt University Medical Center is a top-20 NIH-funded academic research institution. It consists of Vanderbilt University Hospital; Vanderbilt University School of Medicine; The Vanderbilt-Ingram Cancer Center, an NCI Comprehensive Cancer Center; the Vanderbilt University School of Nursing and Vanderbilt Children's Hospital.