Influenza causes more deaths in the United States than all other vaccine-preventable diseases combined, causing an estimated 36,000 deaths annually.¹ However, adult vaccination rates are moderate at 67% for those ≥65, 42% for those 50–64 years of age and 32% for those 18–49 years old with high risk conditions, with racial disparities in rates.²

Missed opportunities, namely failure to vaccinate at all visit types, and infrequent preventive care visits contribute to low rates.^3;4 Standing orders programs (SOPs) are a powerful way to reduce missed opportunities and to raise rates, as they enable non-physician medical personnel to assess patient immunization status and administer vaccines without direct physician involvement. Recent studies demonstrate the effectiveness of SOPs across a spectrum of outpatient settings.^5;6;7 When SOPs are used in combination with other strategies, immunization rates increase by approximately 16 percentage points.⁸ The Advisory Committee on Immunization Practices (ACIP),⁹ the Task Force for Community Preventive Services,¹⁰ and the Southern California Evidence-Based Practice Center-RAND¹¹ have endorsed SOPs for improving immunization rates.

Despite this evidence, SOPs are not commonly used in the outpatient setting. Szilagyi et al. reported that in 2000–01, only 33% of a national sample of 220 physicians who reported providing adult vaccinations were using SOPs and 36% were willing to try SOPs.¹² That study was concurrent with the ACIP recommendation to use SOPs but predated an important change in the Medicare regulations in 2002 that allowed an exception for adult immunizations to the prohibition on SOPs for medications.¹³ This study was designed to determine the prevalence, correlates of use and physicians’ adoption readiness for SOPs for influenza vaccine in the outpatient setting nearly a decade later.

Of the 1640 physicians contacted by mail, 107 were deceased, no longer in practice, unknown at the practice, or not in primary care, and 16 surveys were returned as undeliverable, leaving 1517 eligible physicians. Of these, 1015 physicians returned surveys for a response rate of 67%. Participation was slightly higher among family physicians (68.9%) than internists (64.8%; P<.01), and among board certified physicians (68.9%) than non board certified (60.7%; P<.01). Participants and nonparticipants did not vary by age (mean=50.7 years), length of time in practice (mean=23 years), domestic vs. international training, or geographic region.

One hundred fifteen physicians (74 internists and 41 family physicians; P<.001) reported not immunizing adults at their practices and were not included in the analyses, leaving a sample size for analysis of 900.

Internists were significantly less likely to perform influenza immunization on site; 15.4% of internists reported not vaccinating adults in their practices compared to 7.7% of family physicians (P< .001). Excluding these, as well as a small number who did not provide information on standing orders (~2% in both groups), the prevalence of consistent use of SOPs was 42.4% (38.9% among internists and 46.3% among family physicians). Because weighting for non-response showed similar results (weighted prevalence of SOP use = 42.3%), only unweighted results are presented.

In analyses comparing the four SOP groups, physicians differed in several dimensions, including awareness of recommendations and regulations regarding SOPs for vaccines, size and type of practice, number and level of training of clinical staff, attributes of the staff such as level of teamwork and openness to innovation, and technological capabilities such as electronic medical records, electronic prompts and reminders (Table 1).

Table 2 shows the results of the logistic regression model. The most important factors associated with greater likelihood of a practice consistently using SOPs were: being aware of the ACIP recommendations or Medicare regulations regarding adult immunizations, agreeing that SOPs are effective, and having two or more clinical staff per physician. Other important factors were being a family physician, having an office staff that works well together and is open to innovation, having an electronic medical record (EMR), and having an immunization champion in the practice. Including additional indicators of variation in tracking influenza immunization (paper chart vs. EMR) or type of patient reminder did not change these results; hence they are not included in Table 2 (results available upon request).

In 2000–2001, Szilagyi et al. reported that 33% of a national sample of 220 physicians who reported providing adult vaccinations, were using SOPs.¹² Nearly a decade later, only 42% of primary care physicians were consistently using SOPs for influenza vaccination of adults. This finding raises the question of how to improve use of SOPs in primary care.

Factors associated with consistent use of SOPs include awareness about CDC/Centers for Medicare and Medicaid Services (CMS) stance on standing orders policies, strength of agreement about the power of SOPs, staffing (i.e., number of assistants to help each clinician), and use of EMRs. The CDC has recommended SOPs for adult vaccination since 2000.⁹ However, CMS prohibited SOPs for all medications until 2002 when CMS allowed SOPs for influenza and pneumococcal polysaccharide vaccines.^13;17 These changing policies may have left some physicians unsure about using SOPs for adult vaccination.

The strength of agreement about the effectiveness of SOPs was a key predictor for their adoption in these data. SOPs have resulted in larger increases in vaccination rates than either patient-oriented strategies such as education or provider-oriented strategies such as physician reminders.^8;18 Two aspects of the Awareness to Adherence model of physician adoption of vaccines,¹⁴ awareness of, and agreement with the effectiveness of the SOPs were associated with use of SOPs, suggesting a need for wider and more intentional dissemination of this information.

Two practice characteristics that indicate level of resources available to practices were also associated with SOPs: the number of helpers per clinician and EMR usage. Given the fact that influenza vaccination rates are frequently lower among practices in disadvantaged neighborhoods, SOPs may help reduce these disparities. Use of SOPs by nursing personnel is facilitated by EMR functions that ease record keeping and tracking of vaccination status.¹⁹ CMS plans incentives for EMR usage²⁰ which may further facilitate use of SOPs and eliminate one source of resource disparity. Furthermore, targeting those who adopt EMRs for also implementing SOPs may be an efficient way to increase their use and increase adult immunization rates.