Influenza Vaccination Coverage Level at a Cystic Fibrosis Center
Authors: Marshall Bruce C. , Henshaw Carmen , Evans Dee Anne , Bleyl Kristin , Alder Stephen , Liou Theodore G. 
Published: August 2004

Background. Influenza causes substantial morbidity and mortality, particularly in vulnerable populations. Annual vaccination is the most effective means to prevent or attenuate this illness. The vaccine is recommended for patients with cystic fibrosis (CF) older than 6 months, but the degree of adherence with this recommendation is unknown.
Objectives. To determine 1) the vaccination coverage level for the 1997–1998 influenza season in a population of CF patients, and 2) the factors associated with nonadherence with vaccination.
Design. Retrospective chart review, a mailed survey, and telephone interviews.
Setting. Intermountain CF Center. This center, accredited by the CF Foundation, delivers health care to affected individuals throughout the Intermountain West. Care of children and adults is based at Primary Children’s Medical Center and the University of Utah Hospital, respectively. The adjacent hospitals are comprehensive, tertiary care medical centers on the University of Utah campus in Salt Lake City. Approximately one third of the center’s patient population lives in southern Idaho. There are 2 affiliate centers in Idaho, one based in Pocatello/Idaho Falls and the other in Boise.
Patients. All patients over 6 months of age on the center’s roster.
Results. We found documentation of influenza vaccination status in the medical records of 99 patients; 98 who received the vaccine and 1 who did not because of an allergy to egg products. Through the mailed surveys and telephone interviews, we collected data on 236 additional patients. Thus, we report data on 335 (92.5%) of 362 patients on the center’s roster. A total of 256 (76.4%) of 335 patients received the influenza vaccine before the 1997–1998 flu season, including 181 (79.4%) of 228 children (&lt;18 years of age) and 75 (70.1%) of 107 adult patients (≤18 years of age). We also analyzed the data assigning all patients to their major site of care, either the Salt Lake parent center or one of the Idaho affiliates. We found no difference in the vaccination rate when comparing parent center to affiliates: 179 (78.2%) of 229 paients at the parent center were vaccinated versus 77 (72.6%) of 106 patients at the affiliates. For the 79 patients who did not obtain the influenza vaccine, the major reasons were: “forgot,” “too healthy,” “too busy,” “worried about the side effects,” or “too sick at the time.” The unvaccinated group had fewer clinic visits, fewer CF-related hospitalizations, and lived further from the care center than the vaccinated group. To further explore the association between contact with the center and vaccination status, we categorized patients into those who were evaluated in the outpatient clinic and/or hospitalized in 1997 and those who were not. We found that 80.8% of the 281 patients who actually received care at the center during 1997 were vaccinated as compared with only 59.5% of the 42 patients who did not receive care during that year. The timing of clinic visits also appears to be a critical factor. We found that 87.1% of patients who had a visit during the fourth quarter of the year had the vaccination as compared with 64.9% of patients who did not have a fourth quarter visit. A fourth quarter visit remained highly associated with vaccination in a logistic regression analysis, whereas number of clinic visits did not.
Conclusions. The vaccination coverage level in this vulnerable population is higher than other high-risk groups of comparable age. Nonetheless, there is room for improvement. Strategies aimed at increasing patient contact with the CF center, particularly during the fourth quarter of the calendar year, may result in improved vaccination rates. Additional data encompassing a cross-section of CF centers would be helpful in ensuring that influenza vaccination is receiving adequate attention in this patient population. Systematic monitoring of influenza vaccination rates at a national level should be considered as a means of encouraging compliance with this important preventive measure. cystic fibrosis, influenza, vaccination, health care delivery.