Flu Vaccination Rates Lag For At-risk Adolescents

The research, published in Pediatrics, was based at the Department of Ambulatory Care and Prevention at Harvard Medical School and Harvard Pilgrim Health Care.

"Influenza vaccination has been recommended for adolescents with high-risk conditions for well over a decade," notes lead author Mari Nakamura, a clinical fellow in pediatrics at Children's Hospital Boston. "We wanted to examine how effective this risk-based policy has been in achieving vaccination coverage."

Each year, between 20 and 40 percent of children and adolescents come down with the flu. For children with certain high-risk conditions, this can lead to severe illness, hospitalizations, and in some cases, even death. Because of this, the Centers for Disease Control strongly recommends that all adolescents vulnerable to influenza complications get vaccinated.

The study charted vaccination rates from 1992 to 2002 for 18,703 adolescents with asthma, cardiac disease, immune system disorders and other high-risk conditions who received care at Harvard Vanguard Medical Associates and were insured through Harvard Pilgrim Health Care. The investigators also identified medical visits for checkups and other preventive care that these adolescents had during flu seasons to determine whether there were missed opportunities for vaccination.

Vaccination rates improved during the study period, but only from 8 percent to 15 percent. During the last four years of the study period, 1999 to 2002, only 11 percent of adolescents with high-risk conditions received vaccinations during all four seasons. Over 56 percent of adolescents received no flu vaccinations during this four-year period.

Missed opportunities were common as approximately 45 to 55 percent of high-risk adolescents had one or more health care visits during the flu season at which the vaccine was not administered. In contrast, those who had preventive care visits were more likely to receive influenza vaccine.

Grace Lee of the Department of Ambulatory Care and Prevention, and senior author on the current study, published another study in the October issue of Pediatrics. In that study she found that among adolescents who had not been vaccinated for tetanus-diphtheria (Td), 75 percent did not receive an immunization despite visiting a healthcare provider.

Since 2005, three additional vaccines to prevent meningococcal disease, pertussis, and human papillomavirus have been approved and recommended for adolescents in the US. The introduction of these new vaccines has generated interest in improving how we track adolescent vaccinations.

The study team concludes both patients and providers need to be part of any intervention strategy aimed at increasing vaccination rates among this population. Previous research has also shown that letters to parents and electronic reminders for providers can be effective at improving vaccination rates.

The new recommendation for universal influenza vaccination of children and adolescents, issued by the CDC's Advisory Committee on Immunization Practices this past spring, may help to assure that adolescents are protected against the disease.

Dr. Nakamura observes, "Our findings lend support for the simplicity of universal vaccination. More adolescents, especially those with high-risk conditions, may be vaccinated if providers and parents don't first have to identify who meets criteria for vaccination, as under a risk-based approach."