HELSINKI—A Finnish study suggests that administration of a pneumococcal conjugate vaccine to infants could prevent a large number of acute otitis media cases annually.[1] “The vaccine reduced the rate of acute otitis media from any cause by 6%,” reported Terhi Kilpi, MD, PhD, one of the study authors.

Twenty million cases of pediatric acute otitis media occur in the United States each year, and Streptococcus pneumoniae infection is the most commonly reported cause. Even a reduction as small as 6% could translate into 1.2 million fewer cases annually.

Pneumococcal vaccination was found to be highly effective for preventing acute otitis media cases caused by the pneumococcal serotypes included in the vaccine, decreasing the incidence of these infections by 57%. The vaccine also reduced the rate of culture-confirmed pneumococcal cases by 34%. “However, the 6% overall decrease is probably most relevant for parents concerned about recurrent acute otitis media in their children,” Dr. Kilpi, head of the Department of Vaccines at the National Public Health Institute in Helsinki, said in an interview with RESPIRATORY REVIEWS.

A RANDOMIZED TRIAL

The prospective, randomized, double-blind trial was designed to assess two heptavalent conjugate vaccines, which contained the pneumococcal serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F, conjugated either to the nontoxic diphtheria-toxin analogue CRM197 or to meningococcal outer membrane protein complex. The authors published only their findings for the CRM197 vaccine.

A cohort of 1,662 infants received either that vaccine or a hepatitis B vaccine (the control group) intramuscularly at ages 2, 4, 6, and 12 months. The infants also received routine preventative vaccinations for diphtheria, tetanus, pertussis, polio, Haemophilus influenzae type b, mumps, measles, and rubella according to accepted schedules.

Follow-up lasted until age 24 months. Acute otitis media was defined as abnormal tympanic membrane color, position, or mobility suggesting middle-ear effusion, and at least one of the following: fever, earache, irritability, diarrhea, vomiting, acute otorrhea not caused by otitis externa, and other symptoms of respiratory infection.

EFFICACY AND SAFETY

Overall, there were 2,596 episodes of acute otitis media from any cause; 1,251 occurred in the vaccine group and 1,345 in the controls. The incidence of the infection was 1.16 per person-year in the vaccine group and 1.24 per person-year in the control group. The number of cases of culture-confirmed pneumococcal acute otitis media was 271 and 414, respectively. Cases due to serotypes included in the vaccine numbered 107 and 250, respectively. The vaccine also markedly decreased the incidence of acute otitis media from serotypes that cross-react with those in the vaccine. There was a concomitant rise in cases due to all other serotypes among the infants given the vaccine.

The vaccine appeared to be equally effective in preventing a first episode of otitis media caused by any of the vaccine serotypes and in preventing subsequent episodes (52% and 45% efficacy, respectively). In addition, the vaccine was well tolerated, typically producing only mild local reactions and fever.

“It is currently approved only for invasive pneumococcal disease,” related Dr. Kilpi. “However, an FDA application for otitis media is pending.”

--Timothy Begany