Sandra Yin

May 14, 2012

May 14, 2012 (Baltimore, Maryland) — Smaller pediatric offices achieve better influenza vaccination rates than their larger counterparts, according to a study presented here at the National Foundation for Infectious Diseases (NFID) 15th Annual Conference on Vaccine Research.

For every 10-fold increase in the number of total patients under an office's care, there was a 20% to 24% decrease in vaccination coverage.

Typically, the small offices had 1 to 3 providers, and the average number of patients per provider was 2500 to 3000, said lead researcher Seth Toback, MD, MMM, FAAP, director of medical affairs at MedImmune, and a self-described "recovering" pediatrician.

Dr. Toback speculated that larger practices have more challenges identifying and actually implementing vaccination programs. "It could just be that larger offices have a harder time getting people contacted and scheduled, sending out reminders, and then consequently vaccinating them," he said.

"It's also possible that smaller offices have a larger proportion of physicians who are practice owners or decision makers about vaccines, and therefore they act in a different way." It could also be easier for providers and staff in smaller offices to get on board and align themselves with one vaccination philosophy, Dr. Toback noted.

As offices grow, he said, they really need to evaluate barriers to vaccination and create an environment that is proactive about increasing vaccination rates.

It is critical to do influenza vaccinations in an efficient way, according to Dr. Toback. Unlike adults, 90% of children are vaccinated in outpatient offices, clinics, or health departments. All children 6 months and older are supposed to get flu vaccinations, and the amount of time in which to deliver the vaccine each year is limited.

Surprisingly little is known about what goes on in terms of influenza vaccination in pediatric offices, he said. Previous work on the topic has used survey or claims data, but few studies have prospectively gathered flu vaccination information.

The goal of the multiyear observational study was to evaluate the characteristics and activities associated with influenza vaccination coverage — or the receipt of at least 1 dose — in pediatric offices in the Unites States. The study prospectively captured data on influenza vaccinations by age group and activities aimed at increasing vaccine uptake during 4 influenza seasons (2007/08 to 2010/11).

The American Medical Association list of pediatricians was used to randomly invite pediatrics offices to participate in the study. Researchers assessed vaccination coverage for children 6 months to 18 years of age in 36, 76, 82, and 103 pediatric offices during the 2007/08, 2008/09, 2009/10, and 2010/11 influenza seasons, respectively. Offices had to be solely pediatrics, not associated with a hospital, and able to accurately determine the number of patients under their care.

Every 2 weeks, the researchers would get the exact count of all influenza vaccinations by age group and information on activities undertaken to increase vaccine uptake. Vaccination coverage was defined as the number of children receiving at least 1 dose divided by the total number of children under the office's care. Coverage data came from a large check sheet posted on the refrigerator; in theory, every time a vaccine was taken out, someone made a check mark.

Data collected included office demographics, timing of vaccine availability, staff support of influenza vaccination, in-office activities to promote vaccination, and local influenza vaccination activities (such as school programs or mobile clinics).

On regression analysis, they found that pediatric offices with fewer patients under care had higher vaccination coverage.

When the offices that were in the largest quartile by size were compared with those in the smallest quartile, the difference in vaccination rate was significant. For example, in 2010/11, the vaccination rate for offices in the largest quartile (10,025 to 32,827 patients) was 16.3%, compared with 38.2% for offices in the smallest quartile (629 to 2778 patients). Only seasonal vaccination doses were counted in the pandemic year.

"I found the results of this study to be interesting, but maybe not surprising," said moderator Susan Rehm, MD, conference cochair and medical director for NFID. "There's a possibility that in larger settings, the patients get lost in the crowd, so it becomes a challenge of breaking down that practice into smaller units and reaching out to patients individually."

Dr. Toback did note some study limitations. Although offices were randomly invited to participate in the study, their desire to participate most likely created a selection bias. But the high interoffice variability suggests that selection bias likely did not substantially affect the results, he said. Because the researchers required offices to accurately count their patients, the offices in the study likely had better infrastructure than most, in the form of good billing software or electronic health records.

This study will be published in Clinical Pediatrics.

This study was sponsored by MedImmune. Dr. Toback is employed by MedImmune. Dr. Rehm reports serving as an advisor or consultant for Merck & Co. and Pfizer, and as a speaker for Genentech.

National Foundation for Infectious Diseases (NFID) 15th Annual Conference on Vaccine Research: Session S10. Presented May 7, 2012.


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