OAKLAND, Calif. - An investigational pneumococcal vaccine reduced episodes of otitis media and the need for insertion of ear tubes, according new clinical data presented here at the Pediatric Academic Societies meeting.
A review of medical records of children who participated in the study showed that of the 47,000 doctor visits due to otitis media (OM) recorded during the three-year trial, there were 8.9% fewer visits in the pneumococcal vaccine group than in the comparison group, according to the lead investigators of the study, Steven B. Black, MD, and Henry Shinefield, MD, codirectors of the Kaiser Permanente Vaccine Study Center.
In the primary analysis of all acute OM episodes (33,000 during the trial), children receiving the seven-valent pneumococcal vaccine had 7% fewer new episodes than the placebo group. In additional analysis, children in the vaccine group were 20.3% less likely to require surgical insertion of ear tubes and 22.8% less likely to have frequent bouts of ear infections (five episodes in six months or six episodes within 12 months).
"While we cannot prevent all childhood ear infections, this vaccine has the potential to prevent more than 2 million doctor visits each year in the United States due to ear infections," said Shinefield. "Most important, the cases we prevent are the most threatening because they are caused by the strains of pneumococcus that have most frequently been associated with antibiotic resistance. With this vaccine we will be able to reduce children's suffering, their parents' anxiety and health care costs as well."
The phase 3 randomized, double-blind clinical trial involved more than 38,000 children. The pneumococcal vaccine was administered at 2, 4, and 6 months of age with a booster given at 12 to 15 months of age.
The primary results of the trial were released in September 1998 and revealed that the investigational pneumococcal conjugate vaccine developed by Wyeth-Lederle Vaccines was effective in preventing invasive disease, including pneumococcal meningitis and bacteremia, caused by the seven strains of Streptococcus pneumoniae most common in the United States.
The vaccine used in the trial was formulated to prevent those seven strains, which represent up to 85% of all invasive disease due to pneumococcal bacteria in children. Of the 47 cases of invasive diseases diagnosed so far since the trial began, none were among the children immunized with the pneumococcal vaccine.
Approximately 95% of U.S. children experience at least one episode of OM by age 6, and about 60% of the cases are caused by bacteria, 40% of which are pneumococcus. Infections by pneumococcus are the least likely of other OM-causing bacteria to resolve without treatment.
Pneumococcal disease has traditionally been treated with antibiotics, but the emergence of pneumococcal strains resistant to penicillin and other antibiotics has created a need for a pneumococcal vaccine effective in infants and young children. The currently available pneumococcal polysaccharide vaccine is available to protect against pneumococcal disease, but it is not effective in children younger than 2 years and is not indicated for protection against OM.
For more information:
- Rennels MB, Edwards KM, Keyserling HL. Safety and immunogenicity of heptavalent pneumococcal vaccine conjugated to CRM197 in United States infants. Pediatrics. 1998;101(4):604-611.
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