January 28, 2000

Study finds skipping flu shots costly in long run

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Dr. Marie Griffin

Study finds skipping flu shots costly in long run

A Vanderbilt University Medical Center researcher has found that it could be far more costly for children to miss annual flu vaccines than previously thought.

In an epidemiological study published in this week's New England Journal of Medicine, Dr. Marie R. Griffin, professor of Preventive Medicine, analyzed the total disease burden — including hospital visits, outpatient visits, and use of antibiotics — in children during a 19-year period. The results indicate affects exceeding previous estimates.

Using records from healthy children under the age of 15 enrolled in the Tennessee Medicaid program, researchers were able to estimate the average number of hospitalizations, doctor visits, and antibiotic prescriptions due to influenza.

"We know that every year about 30 percent of children get the flu and school-aged children help spread flu in the community," Griffin said.

The study showed that among infants, the risk of hospitalization is relatively high and actually similar to that of elderly persons. For school-aged children, hospitalizations are uncommon. However, the data showed that flu resulted in substantial use of outpatient medical resources.

Each year, there are about 10 physician visits for flu, or for the middle ear infections that often develop as a result of flu, for every 100 children. In addition, more than half of these visits result in an antibiotic prescription.

The researchers also noted that along with the days of misery and missed school for the child, the illness can be expensive and inconvenient for parents or caregivers and can result in time lost from work.

"This study will help determine whether recommending influenza vaccine for all children would be a cost effective national policy," Griffin said. "Potential benefits of influenza vaccine include a decrease in physician visits, antibiotic use and decreased spread of the virus to others in the community.

"There is a big push to decrease antibiotic prescribing since overuse has resulted in the emergence of resistant organisms. Vaccinations against respiratory viruses have great potential for decreasing antibiotic use."

Clinical trials have shown that influenza vaccines, including both the currently licensed flu shot and the not yet approved nasal spray vaccine, reduce middle ear infections and associated antibiotic use by between 20 and 30 percent.

The Advisory Committee for Immunization Practices to the Centers for Disease Control and Prevention (CDC) currently recommends influenza vaccine for: all persons age 65 years and older (soon to be changed to age 50 and older); anyone age six months and older with a chronic medical condition; those who live and work at high risk for serious influenza illness, including all health care workers; and to anyone who wants to avoid influenza illness.

"Several factors need to be weighed before we recommend that all children receive influenza immunizations every year,” said Griffin.

The influenza vaccine is different from other childhood vaccines in that it is different each year. The influenza virus changes quickly and vaccine manufacturers make a new vaccine each year based on estimates of which strain of virus or viruses might circulate.

The vaccine is optimally given between October and December, and a common parental objection to annual vaccination is that bringing healthy children to the doctor’s office every year for a flu shot is inconvenient, especially for school-aged children.

The new nasal vaccine may be more acceptable to children and parents. In addition, new ways of distributing the vaccine, which do not require a scheduled visit to a physician’s office, could make immunization more cost-effective.

Griffin's study was done in collaboration with Dr. Kathleen Neuzil, former Vanderbilt Infectious Disease faculty member, now at the University of Washington Seattle; Dr. Beverly Mellen, biostatistician in Preventive Medicine, currently at Bowman Gray; Peter Wright, Chief of Pediatric Infectious Diseases; and Ed Mitchel, computer programmer and analyst in Preventive Medicine.