Researchers from the Czech Republic report, a successful trial of a vaccine for acute otitis media, the inner ear condition that is the most common bacterial infection in children.
The vaccine contains proteins from 11 different strains of the bacterium Streptococcus pneumoniae that are attached to a protein from another infectious agent, Haemophilus influenzae. Thus, the vaccine protects against the two main causes of middle ear infections, the researchers say.
The study included nearly 4,700 infants, ages three to 15 months, who were followed-up until the end of their second year. Half of the infants got the vaccine and half were given a hepatitis A vaccine to serve as a control group.
The researchers found 333 cases of acute otitis media in the group that received the vaccine compared with 499 ear infection cases in the control group.
Therefore, the incidence of ear infections in the children who were given the vaccine was one-third lower than in those who didn't receive it, according to doctors at the University of Defense in Prague.
The study results are "very exciting" but still preliminary, says Dr. Allan S. Lieberthal, a pediatrician at Kaiser Permanente in California and cochairman of the American Academy of Pediatrics' and American Academy of Family Physicians' subcommittee on the management of acute otitis media.
Lieberthal says he is cautious because of the criteria used in the study to define acute otitis media. He was a member of the committee that drew up criteria to distinguish an ear infection that requires antibiotics from otitis media with effusion, or an accumulation of fluid in the middle ear, a condition that usually clears up on its own.
While the committee criteria for an ear infection requires an onset of symptoms within 48 hours, the Czech study accepted cases that were diagnosed as late as 14 days afterward, Lieberthal says. In addition, the study did not require signs of inflammation, another criterion set by the committee.
"If this is reproduced in other studies and the vaccine is safe, it would suggest that the vaccine would decrease infection by those bacteria and possibly result in a reduction of acute otitis media," Lieberthal says. "But before you say' this is an acute otitis media vaccine,' you have to do studies using a better definition of acute otitis media," he adds.
Still, Lieberthal's caution is coupled with enthusiasm. The trial results "strongly suggest" that the vaccine protects against infection, and he says, "I think it is a very important vaccine."
Drug maker GlaxoSmithKline plans to market the shot as Streptorix. The vaccine is undergoing Phase 3 trials, the final set of tests that is needed to seek approval for marketing a pharmaceutical product.