Influenza vaccine rates poor among high-risk adolescents

Internal Medicine News, Feb 15, 2008 by Doug Brunk

SAN DIEGO -- The number of adolescents with asthma and other high-risk conditions who received the influenza vaccine increased between 1992 and 2002, but the coverage remains poor at about 15% overall, results from a large HMO study showed.

"About 85% of these kids who should have been getting the vaccine weren't getting it," Dr. Mari M. Nakamura said in an interview during a poster session at the annual meeting of the Infectious Diseases Society of America. "A risk-based approach to vaccination isn't working in this population. Universal vaccination in this age group may be warranted instead."

She and her mentor, Dr. Grace M. Lee, reviewed the medical records of 18,703 patients aged 11-17 years with high-risk conditions who were enrolled in Harvard Pilgrim Health Care for at least one influenza season and the preceding 1-year period, from 1992 to 2002.

High-risk conditions were indicated by ICD-9 diagnoses, and included asthma or other chronic pulmonary disease, chronic cardiac disease, immunosuppressive disorders or therapy, sickle cell anemia or other hemoglobinopathy, chronic renal dysfunction, or chronic metabolic disease.

"The burden of influenza is especially high in children and adolescents with high-risk conditions, accounting for excess hospitalizations, outpatient visits, and antibiotic courses," the researchers wrote.

They evaluated the changes in influenza vaccination rates over the time period, as well as the number of missed opportunities for vaccination (defined as office visits during the first 4 months of influenza season at which an unvaccinated adolescent was not vaccinated).

The mean age of patients was 14 years, and 48% were female, reported Dr. Nakamura, a Harvard pediatric health services research fellow at Children's Hospital Boston. The majority of patients (90%) had asthma or other chronic pulmonary disease, whereas 2% had more than one high-risk condition.

Influenza vaccination rates improved significantly from 1992 to 1993 (from 8.3% to 12.8%), and then again from 1993 to 2002 (from 12.8% to 15.4%).

The researchers also noted that between 1992 and 2002, about half of all unvaccinated patients had at least one missed opportunity for vaccination.

"The main reasons that they came in included preventive care and the need for other vaccinations," she said. "This tells us that providers are a group to target, to remind them that these patients should be getting flu vaccine every year."

The study was funded by Harvard Pilgrim Health Care and by the Agency for Healthcare Research and Quality. The researchers disclosed that they had no conflicts of interest.

BY DOUG BRUNK

San Diego Bureau