Volume 123, Issue 11 , Pages 1031-1035, November 2010
Improving Influenza Vaccination Rates by Targeting Individuals not Seeking Early Seasonal Vaccination
Article Outline
Abstract
Background
Influenza morbidity and mortality remain high in the United States although vaccination clearly improves health outcomes and reduces health expenditures. This study was designed to assess the effectiveness of mail and telephone reminder strategies on improving existing clinic influenza vaccination rates among those not seeking early seasonal vaccination.
Methods
In mid-November, we randomized 1371 patients at a hypertension clinic into 1 of 2 intervention groups, a mail reminder group (letter plus the Centers for Disease Control [CDC] Influenza Vaccine Information Statement) or a phone reminder group (same information via a personal phone call), or a control group. The following spring, records were reviewed for vaccination documentation. Patients without documentation were contacted by phone to identify whether vaccination for the current season had been obtained.
Results
The final analysis included 884 patients (62% women, mean age 57.2 years old): 325 in the mail reminder group, 246 in the phone reminder group, and 313 represented the control group. Overall, 388 of these patients (44%) were vaccinated. Vaccination rates were significantly higher in the intervention groups, 46% for the mail reminder group (age and sex adjusted odds ratio [OR], 1.8, 95% confidence interval [CI], 1.3-2.5; P
=.001) and 56% for the phone reminder group (OR, 2.8; 95% CI, 1.9-4.0; P<.0001), compared to 33% in the control group. Both interventions increased vaccination rates in all age/sex groups.
Conclusion
In contrast to earlier studies, this intervention occurred later in the influenza vaccination period excluding those who seek early vaccination and allowing interventions to target those less likely to receive vaccination. Compared to previous studies demonstrating only trivial or modest benefits, both mail and phone reminders effectively increased clinic vaccination rates in our group of patients.
Keywords: Ambulatory services, Influenza, Reminder strategies, Vaccination rates
Epidemics of influenza result in significant hospitalizations, morbidity, and mortality each year.1, 2, 3 While vaccination is the most effective means for reducing influenza infections, immunization rates are moderate and are far from the goals of the national Healthy People 2010 objective.1, 4, 5 Persons at increased risk for complications and death from influenza are those at the extremes of age and those with chronic medical conditions.1, 2 Non-elderly persons with chronic diseases also are more likely to require hospitalization and miss time from work.3 Among individuals with chronic medical conditions, influenza mortality is more common in those with cardiovascular disease than those with any other chronic condition.2, 3 Vaccination has been demonstrated to be very cost-effective in preventing disease, reducing hospitalizations, and reducing mortality among both elderly and healthy working adults.1, 4, 5, 6, 7, 8, 9
The majority of patients encountered at the University of Mississippi Medical Center Hypertension Clinic qualify for influenza vaccination. Although hypertension itself is not a specific qualifying disease according to recommendation guidelines, most of our patients have other chronic conditions including cardiovascular, metabolic diseases, or renal dysfunction. Others qualify based on age recommendations or because they live with or care for persons at high risk for influenza-related complications.1, 4, 5, 7, 9 Immunization may not be commonly perceived as falling under the realm of this type of subspecialty practice.10 However, our approach is comprehensive and we recognize the benefit of influenza vaccination for our patients and see vaccination as an opportunity for improved quality of care. The American Heart Association and American College of Cardiology now also recommend that health care providers who treat individuals with cardiovascular disease make focused efforts to help improve influenza vaccination rates.2
Reminder/recall systems, standing order programs, and assessment of practice-level vaccination rates are among the methods recommended to improve vaccination levels.1, 5, 7, 11, 12, 13, 14, 15 Our clinic has had an existing standing order policy in place since 1998 under which the pharmacist recommends and administers routine vaccinations. Throughout the summer, we also encourage patients to sign-up to receive a vaccination in the first 2 weeks of October. As observed in our clinic, most influenza vaccinations typically occur early in the immunization season with rates of vaccine administration decreasing substantially after November.9 The purpose of this study was to evaluate and assess the effectiveness of mail or telephone reminder strategies on improving existing influenza vaccination rates among those not seeking early seasonal vaccination within our clinic population.
Methods
This project and data collection corresponded with the annual influenza season. The project was timed to begin after mid-November to exclude those who actively seek vaccination early in the season and potentially include those less likely to receive vaccination. After institutional review board approval was received, an initial review identified 1712 patients with at least one clinic visit within the previous 15 months. After excluding 341 patients with clinic medical record documentation of recent influenza vaccination, patients were randomized into 3 groups: 2 intervention groups (mail reminder or a phone reminder) and a control group (standard clinic practice). Patients randomized to the mail reminder group received a letter via US mail addressed from the clinic and signed by the clinic pharmacist and physician medical director and a copy of the Centers for Disease Control and Prevention (CDC) Influenza Vaccine Information Statement. Patients in the phone reminder group received a personal phone call from a doctor of pharmacy resident within the clinic. Phone calls were made between the hours of 8:00 am and 8:00 pm. A minimum of 5 call attempts were made on different days and times. Both groups received the same information regarding the influenza vaccination, including explanations of the importance of receiving the vaccination and indications. Vaccination was encouraged, although not specifically at our site. Our clinic charge for vaccination was provided at all encounters and the mention of possible less expensive options (ie, state public health clinics).
The following spring, records for all included patients were initially screened for documentation of influenza vaccination. Those without documentation received a phone call from the same pharmacy resident inquiring about vaccination status and approximate date, if received at another site. Persons who reported over the phone that they had received vaccination prior to the intervention period (at another site, not documented in our clinic medical record), and those who could not be contacted after a minimum of 5 attempts, were excluded from final analysis (n=487), leaving 884 patients available for our study.
Statistical Analysis
The main outcome measure was the number (%) of individuals receiving immunization in the intervention groups compared with the control group. Age-adjusted and sex-adjusted odds ratios (ORs) of being vaccinated and 95% confidence intervals (CIs) were calculated using logistic regression (SAS Proc Logistic, SAS Institute, Cary, NC). In all regression models, the age by sex interaction term was not statistically significant and was dropped.
Results
The study population was comprised of 884 patients: 325 patients in the mail reminder group, 246 patients in the phone reminder group, and 313 patients in the control group. The mean age was 57.2 years old (SD 13.8; range, 16-97 years), with 29% aged 65 and older and 43% aged 50 to 65 years old; 551 patients (62%) were women. Compared to the control group and the phone groups, the mail group had a slightly higher percentage of women (65% vs 61% in each of the other groups). The mail group also had a slightly higher mean age (57.7 years old) compared to the phone or control groups (56.9 years old in each).
Overall, 388 patients (44%) in the study population were vaccinated. Vaccination rates were significantly higher in the intervention groups: 46% in the mail reminder and 56% in the phone reminder groups, compared to 33% in the control group. Vaccination rates increased with age, from 30% in those less than 50 years of age to 43% in those aged 50 to 65 years and 59% in those over age 65. Vaccination rates were approximately 8% higher in men than women (49% vs 41%).
Although both phone and mail reminders were more effective than control, phone reminders resulted in higher vaccination rates with a better response in all age/sex groups (Table 1). The crude (unadjusted) and age/sex-adjusted ORs of being vaccinated are provided in Table 2. While the mail reminder significantly increased the odds of being vaccinated (adjusted OR, 1.8; 95% CI, 1.3-2.5; P<.001), phone reminders nearly tripled these odds (adjusted OR, 2.8; 95% CI, 1.9-4.0; P<.0001).
Table 1. Observed Vaccination Rates (%) by Study Group, Age Group, and Sex
| Age group | Sex | Study Group | ||
|---|---|---|---|---|
| Control | Phone | |||
| <50, n=248(30) | Female | 13.5 | 24.1 | 34.1 |
| Male | 29.0 | 36.7 | 61.5 | |
| 50-65, n=379(43) | Female | 29.8 | 47.5 | 57.7 |
| Male | 24.5 | 46.7 | 63.0 | |
| >65, n=257(59) | Female | 50.0 | 54.4 | 58.9 |
| Male | 58.3 | 58.3 | 87.5 | |
| Overall | 43.9 | 32.9 | 45.5 | 55.7 |
Table 2. Crude (Unadjusted) and Adjusted Odds Ratios of Vaccination by Intervention
| OR | 95% CI | P value | |
|---|---|---|---|
| Mail reminder⁎ | |||
| Crude | 1.7 | 1.2-2.4 | .001 |
| Age/sex-adjusted | 1.8 | 1.3-2.5 | .001 |
| Phone reminder⁎ | |||
| Crude | 2.6 | 1.8-3.6 | <.001 |
| Age/sex-adjusted | 2.8 | 1.9-4.0 | <.001 |
⁎Compared to the control group. |
Discussion
The goal of this study was not to increase vaccinations provided at this particular clinic, nor was it to reflect overall immunization rates. The purpose of our investigation was to identify strategies that would increase vaccination rates above baseline in our clinic. In contrast to earlier studies, the intervention occurred after the beginning of the annual influenza vaccination period, excluding early vaccination seekers and allowing interventions and resources to potentially target those of all age groups that are less likely to receive a vaccination. The findings of this study demonstrate that the addition of mail and phone reminder systems implemented by clinic personnel can lead to significant improvements in baseline clinic vaccination rates.
Our findings also reveal that even with significant effort, there are major challenges to achieve the Healthy People 2010 recommended immunization goals in particular populations (90% of adults ≥65 years of age, and 60% for those aged 18-64 years).6 Simultaneous interventions across primary care, subspecialty, inpatient, and community domains still do not achieve immunization rates above 60%. Estimated national vaccination coverage levels in the 2007 to 2008 season ranged from 17.0% to 30.4% in the 18 to 49 age group, 34.1% to 48.4% in those aged 50 to 64 years, and 64.6% to 66.6% in those 65 years and older.5, 6 We observed rates of 30%, 43%, and 59% in these respective age groups among our targeted study population. Our results do not describe our baseline and entire clinic population, but reflect those less likely to receive vaccination. Typically, most influenza vaccinations occur early in the immunization season and rates of administration decrease substantially after November.9
Standing order programs improve vaccination rates and allow other health care providers such as nurses or pharmacists to administer vaccines without the need for a physician's examination or direct order. The CDC Advisory Committee on Immunization Practices recommends the use of standing order programs in both inpatient and outpatient settings.1 This clinic has had standing orders in place since 1998, but no other reminder system other than routine clinic encounters and an early sign-up sheet prior to the vaccination season. Using available personnel and adding mail and phone reminder systems allowed clinic personnel to further the efforts of our existing standing order program by targeting those less likely to receive vaccinations.
Commonly, mass mailings are identified as a possible method of increasing utilization of influenza vaccine. In general, mass mailings have been found to have only trivial effects and are relatively ineffective among Medicare beneficiaries16 and those <65 years of age with high risk of complications.16, 17 Our mail reminder was more personalized in that it was addressed from the clinic and signed by the clinic pharmacist and physician medical director. This investigation demonstrated that mailings do have more than a trivial benefit in this clinic population. Mail reminders were more effective at increasing vaccination rates among women compared to men and were most effective among patients age 50 to 65 years old.
Typically, telephone reminders are identified as a means of improving immunization rates, although they have been only modestly effective.6, 13, 18, 19 Our phone reminders came directly from personnel affiliated with the clinic. Our results indicate that significant improvements can be made in vaccination rates via phone intervention. In addition, we provided either oral or written information regarding the importance of receiving a vaccination with both our phone and mail reminders. Incorporating educational information regarding vaccination importance into personalized reminder strategies may serve to raise awareness, increase vaccination rates, and improve overall patient care.
Most previous interventions have focused on older populations.16, 18 Because recommendations for vaccination span all age groups, we included all of our adult patients. Improved vaccination rates in all groups can translate to appropriate conservation of health care resources, including fewer physician visits and hospitalizations for influenza-related illness and reductions in unnecessary antibiotic prescribing.1, 8
Demographics of those included in the final analysis were representative of our overall clinic population (62.2% women, average age 57.5 years old), although those greater than age 65 were slightly under-represented (29% of study population vs 32% of clinic population). Those presenting for early vaccination in our clinic are often older, as typical at most sites, so older patients may have been disproportionately excluded from our study.9 We observed significant improvements in vaccinations across all age strata.
Limitations
No data on race, education, socioeconomic status, insurance coverage, or chronic medical conditions were collected for this study in our final population or those excluded. These factors were outside the realm of this investigation but would have provided more specific information regarding vaccination status, possible disparities within our population, and potential targets for future interventions. Each study group included many patients who had previously been vaccinated in other settings. Naturally, there were more patients in the phone group that were identified and excluded initially. The only way to prevent this would have been to contact each of these patients prior to randomization, which would have influenced study results. All phone calls were also made by a female pharmacy resident. There were higher predicted vaccination rates among men compared to women in all age groups. We did not look at clinic visits corresponding with our intervention period. Patients in the control group and those in the intervention groups, may or may not have come into the clinic during the study period. As with national surveys, we used self-report of vaccination for all those who were not actually vaccinated in our clinic. In addition, there were patients who were lost to follow-up. This project was labor intensive. An alternative method could be incorporating both mail and phone reminders into existing recall systems over the seasonal vaccination period. These results are specific for our clinic and represent patients that are seen in a referral setting.
Conclusion
Results of this study have helped to more clearly define the role of reminder strategies in improving vaccination rates in our clinic. An intervention later in the vaccination season potentially targets those less likely to be vaccinated. In this population, both mail and phone reminders were effective at increasing clinic vaccination rates, with phone reminders nearly tripling the odds of being vaccinated compared to control. Future research should identify and characterize patient-level barriers to vaccination; determine further strategies to improve rates; examine disparities in vaccination rates; and include a longitudinal economic analysis of interventions.
References
- Prevention and control of influenza (Recommendations of the Advisory Committee on Immunization Practices (ACIP)). MMWR Recomm Rep. 2006;55(RR10):1–42
- Influenza vaccination as secondary prevention for cardiovascular disease: a science advisory from the American Heart Association/American College of Cardiology. Circulation. 2006;114:1549–1553
- . Delivery of influenza vaccine to non-elderly persons with cardiovascular disease, with varying national supply of vaccine: a decision analysis. Hum Vaccin. 2005;1:217–223
- Prevention and control of influenza: recommendations of the Advisory Committee on Immunization Practices (ACIP), 2008. MMWR Recomm Rep. 2008;57(RR-7):1–60
- Prevention and control of seasonal influenza with vaccines: recommendations of the Advisory Committee on Immunization Practices (ACIP), 2009. MMWR Recomm Rep. 2009;58(RR-8):1–52
- [No authors listed.] U.S. Department of Health and Human Services: Office of Disease Prevention and Health Promotion–Healthy People 2010. Nasnewsletter. 2000;15:3
- . Facilitating influenza and pneumococcal vaccination through standing order programs. MMWR Morb Mortal Wkly Rep. 2003;52:68–69
- The effect of universal influenza immunization on antibiotic prescriptions: an ecological study. Clin Infect Dis. 2009;49:750–756
- . National Influenza vaccination week: November 26-December 7, 2007. MMWR Morb Mortal Wkly Rep. 2007;56:1216–1217
- . Generalist and subspecialist physicians' knowledge, attitudes, and practices regarding influenza and pneumococcal vaccinations for elderly and other high-risk patients: a nationwide survey. Arch Intern Med. 2001;161:2702–2708
- . Influenza vaccination of recommended adult populations, U.S., 1989-2005. Vaccine. 2008;26:1786–1793
- Interventions to improve influenza, pneumococcal polysaccharide, and hepatitis B vaccination coverage among high-risk adults: a systematic review. Am J Prev Med. 2005;28(5 Suppl):248–279
- . Patient reminder and patient recall systems to improve immunization rates. Cochrane Database Syst Rev. 2005;(3):
- Interventions that increase use of adult immunization and cancer screening services: a meta-analysis. Ann Intern Med. 2002;136:641–651
- . Improving influenza, pneumococcal polysaccharide, and hepatitis B vaccination coverage among adults aged <65 years at high risk: a report on recommendations of the Task Force on Community Preventive Services. MMWR Recomm Rep. 2005;54(RR-5):1–11
- . Mass mailings have little effect on utilization of influenza vaccine among Medicare beneficiaries. Am J Prev Med. 2002;23:43–46
- Effect of the frequency of delivery of reminders and an influenza tool kit on increasing influenza vaccination rates among adults with high-risk conditions. Am J Manag Care. 2004;10:698–702
- Effect of patient reminder/recall interventions on immunization rates: a review. JAMA. 2000;284:1820–1827
- Interventions aimed at improving immunization rates. Cochrane Database Syst Rev. 2002;(4):
Funding: None.
Conflict of Interest: None of the authors have any conflicts of interest associated with the work presented in this manuscript.
Authorship: All authors had access to the data and played a role in writing this manuscript.
PII: S0002-9343(10)00577-2
doi:10.1016/j.amjmed.2010.06.017
© 2010 Elsevier Inc. All rights reserved.
Volume 123, Issue 11 , Pages 1031-1035, November 2010
