Influenza Vaccination Among Medical Residents in a Teaching Hospital
We assessed the rates of influenza vaccine acceptance and the reasons for acceptance or refusal among medical residents in different disciplines during the 2004‐2005 influenza season. Rates varied among disciplines; emergency department residents had the lowest acceptance rate (24%). The perception of a low risk of contracting influenza was the most common reason reported for vaccine refusal.
Received May 16, 2007; accepted September 14, 2007; electronically published November 19, 2007.
Influenza continues to be a major cause of morbidity and mortality in the United States. The Centers for Disease Control and Prevention Advisory Committee on Immunization Practices recommends annual vaccination for individuals at high risk, including healthcare workers who provide direct patient care.1 Vaccination of healthcare workers has been shown to reduce influenza infection and to decrease the risk of influenza transmission to patients.2 Despite such evidence and strong recommendations from the Advisory Committee on Immunization Practices, influenza vaccination rates among healthcare workers remain low.3
During the fall of 2004 and the early winter of 2005, a nationwide shortage of influenza vaccine increased awareness among the public and healthcare community about the importance of vaccination. Our institution had an adequate supply of vaccine to vaccinate individuals at high risk, including healthcare workers. The influenza vaccine is offered free of charge annually to all medical residents at our institution, and this information is widely publicized throughout the hospital. The influenza vaccine is routinely administered by the employee health services. The influenza vaccine is also offered to residents in internal medicine, pediatrics, and medicine‐pediatrics during their noon conference. In addition, the vaccine is available in the emergency department for emergency medicine residents, where it is administered by a designated staff nurse. The purpose of this study was to examine the rates of influenza vaccination among our medical residents during a time of heightened awareness of the importance of vaccination. The vaccination rates of residents in different specialties and the reasons reported for refusal of vaccination were evaluated.
Methods
In March 2005, an anonymous questionnaire was given to all residents in internal medicine, pediatrics, medicine‐pediatrics, and emergency medicine who were training at our institution during the 2004‐2005 influenza season. The questionnaire was designed to collect information about demographic characteristics, postgraduate year of residency training, acceptance or refusal of influenza vaccination, and history of previous influenza immunization. The data regarding reasons for refusal of vaccination were collected using a multiple choice question. The possible responses that described reasons for refusal of vaccination were “not likely to get influenza,” “not convinced about efficacy of influenza vaccine,” “has concerns about adverse effects of vaccine,” and “previously experienced adverse effects.” Using an open‐ended question, the respondents were asked to describe any previously experienced adverse effects.
The comparison of rates of current or past influenza vaccination according to residency training program and the postgraduate year of residency training, as well as the relationship of previous vaccination history to current vaccination status was conducted using the Pearson χ2test. A P value less than .05 was considered statistically significant. All statistical analyses were performed using SPSS statistical software for Windows, version 14.0 (SPSS).
Results
A total of 105 residents trained at our institution during 2004‐2005; 91 residents (86.7%) responded to our questionnaire: 40.6% were medicine residents, 27.5% were emergency medicine residents, 23.1% were pediatrics residents, and 8.8% were medicine‐pediatrics residents. The questionnaire was completed by 21 (95.5%) of 22 pediatrics residents, 37 (92.5%) of 40 medicine residents, 25 (80.1%) of 31 emergency medicine residents, and 8 (66.7%) of 12 medicine‐pediatrics residents. First‐year residents constituted 30.8% of the respondents; second‐year residents, 25.3%; and third‐year residents, 44.0%. Of the 91 residents who completed the survey, 49 (53.8%) were male.
Of these 91 respondents, 61 (67.0%) had a previous history of influenza vaccination, and 45 (49.5%) of the respondents had received the vaccine during the 2004‐2005 influenza season. Previous vaccination rates did not differ significantly by training program (pediatrics residents, 76.2%; medicine residents, 67.6%; medicine‐pediatrics residents, 62.5%; emergency medicine residents, 60%), but vaccination rates during the 2004‐2005 season varied significantly among residents in different training programs (pediatrics, 66.7%; medicine, 56.8%; medicine‐pediatrics, 50.0%; and emergency medicine, 24.0%; emergency medicine vs other specialties, 
). Overall, previous influenza vaccination was significantly associated with receiving the vaccine during the 2004‐2005 season (
). No significant differences were found in immunization rates by postgraduate year status (
).
Of the 46 residents in the unvaccinated group, 36 (78.3%) gave reasons for not getting vaccinated. Reasons cited for refusal of immunization were “not likely to get influenza,” reported by 21 respondents (58.3%); “not convinced about efficacy of influenza vaccine,” reported by 8 (22.2%); “has concerns about adverse effects of vaccine,” reported by 5 (13.8%); and “previously experienced adverse effects,” reported by 2 (5.6%). No significant difference was found in the perception of the risk of acquiring influenza among emergency medicine residents, compared with the risk perceptions of residents in other disciplines.
Discussion
Although influenza vaccine acceptance among healthcare workers has been evaluated,4 only a few studies have investigated the vaccination status of medical residents.5‐8 In our study, the overall influenza vaccination rate among our residents was 49.5%, which is higher than the national average of 35.7% for healthcare workers, according to the National Health Interview Survey.3 Previous reports have demonstrated varying rates of influenza vaccination among medical residents, ranging from 51% to 82%.5‐7 Data are limited regarding influenza vaccination rates among residents of different training disciplines. Our findings corroborate those of a previous study,7 which showed that the influenza vaccination rate for pediatrics were 75% and the rate for medicine residents was 52.5%.
The low rate of influenza vaccination among our emergency medicine residents is surprising and disconcerting, because emergency medicine residents have a high exposure rate to a large number of patients, especially in an urban hospital during influenza season. Influenza vaccination for emergency medicine healthcare workers is especially important because of its potential to reduce influenza transmission to patients. Similar to our findings, a study conducted in the emergency departments of 4 Ontario teaching hospitals showed that only 35.3% of emergency medicine physicians and residents were vaccinated against influenza.9
In our study, the most frequently reported reasons for refusal of influenza vaccination were the perception of a low risk of acquiring influenza and doubts regarding vaccine efficacy. Other commonly reported reasons for vaccine refusal include procrastination or forgetfulness, inconvenience of being vaccinated, and fear of secondary febrile illness.5‐7 Surprisingly, in one study, nearly one‐third of the respondents thought that they could acquire influenza from the vaccine.5 A randomized, double‐blind clinical trial has demonstrated that other than a higher rate of arm soreness in vaccine recipients, influenza vaccination is not associated with an increased incidence of systemic symptoms when compared with a placebo.10 Despite this evidence, some of the respondents in our study reported fear of adverse effects as a reason for not getting the vaccine.
Several reports from other hospitals have described versatile programs for increasing rates of influenza vaccination. In a study in which medical residents were offered free influenza vaccine in the internal medicine clinics, vaccination rates increased from 24% to 99% during a 9‐year period.8 Although the employee health services performed its own vaccination program for hospital personnel, the active campaign for residents succeeded because most were vaccinated in the internal medicine clinics, a work site that they were required to attend weekly. Ohrt and McKinney5 also showed that by offering the influenza vaccine in clinics and conferences, the immunization rates of medical house staff improved. Similar approaches have the potential to increase vaccination rates among our residents, specifically among emergency department residents.
This study has a few limitations. The survey was conducted in a single institution and during a single influenza season. In addition, all the data in our survey were self‐reported; therefore, the accuracy of the responses depended on the respondents’ recollection of events and their willingness to describe their experiences.
Acknowledgments
We thank Kathryn Bishburg, PharmD, for her helpful suggestions.
Potential conflicts of interest. All authors report no conflicts of interest relevant to this article.
References
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Presented in part: 43rd Annual Meeting of Infectious Diseases Society of America; San Francisco, California; October 6‐9, 2005 (Abstract 967).