Improving influenza vaccination performance in an HMO setting: the use of computer-generated reminders and peer comparison feedback.

We evaluated a program for improving influenza immunization performance in a health maintenance organization (HMO). The HMO implemented several interventions successively from 1984-87: a postcard reminder to members at high risk for complications of influenza, a computer-generated reminder to the physician at the time of any primary care visit by high-risk patients, performance feedback to chiefs of service, and, finally, retrospective feedback to each physician comparing his/her performance with that of the other physicians. We examined immunization rates for a group of members older than age 65, a high-risk group under age 65, and a group of diabetic members who had not been subject to the reminders (vs a group who had been covered by the program). Vaccination rates were increased in those diabetic members who received reminders. Nevertheless, among members younger and older than age 65 whose experience was observed over three flu seasons, a significant increase in vaccination rates was not achieved until physician feedback was added to the program. We conclude that each element of the reminder and feedback program has contributed to the overall increase in vaccination rates at the HMO and that effective ongoing influenza immunization programs can be implemented in practice settings with appropriate systems support.     

The relationship of health beliefs and a postcard reminder to influenza vaccination.

The relationship of certain health beliefs to influenza vaccination and the effect of a postcard reminder on vaccination rates was studied among 232 high-risk patients. In agreement with the Health Belief Model tested, the patients vaccinated believed influenza to be more serious, believed they were more susceptible to influenza, and believed the vaccine to be more efficacious than did patients not vaccinated. Those not vaccinated were less satisfied with their medical care and felt the vaccine was more expensive than those vaccinated. A postcard reminding patients of influenza vaccination was an effective way to increase the vaccination rate. Patients receiving the card had a 59.7 percent vaccination rate compared to a 30.0 percent rate among those not receiving the postcard. This study suggests that a reminder postcard is an effective means to promote influenza vaccination and that these beliefs are important determinants of vaccination behavior.     

Enhancing influenza immunization. Postcard and telephone reminders and the challenge of immunization site shift

OBJECTIVE: To determine if postcard and telephone reminders increased the rate of influenza immunization of Medicare beneficiaries. DESIGN: Before and after trial (postcard reminders) with systematically allocated control group (telephone reminder intervention). SETTING: A semirural family practice residency program. PATIENTS AND OTHER PARTICIPANTS: All 475 noninstitutionalized persons older than 65 years who had received at least 1 office service in the previous 2 years. INTERVENTION: In September 1996, each of 475 patients received a postcard urging prompt influenza immunization. Those not responding within 1 month were systematically allocated either to a group receiving further telephone contact or to a control group. At the time of telephone contact, any offered information about influenza immunization received outside the Smoky Hill Family Practice Center, Salina, Kan, was recorded. MAIN OUTCOME MEASURES: We measured the percentage of change in practice-administered influenza immunizations compared with the baseline rate of the preceding 2 years; the difference in immunization rates between the telephone intervention group and controls; and the number of patients contacted by telephone who reported receiving influenza immunization at a site other than the Family Practice Center. RESULTS: Twenty-eight percent of patients who received a postcard obtained office influenza immunizations within 1 month, but no additional immunizations could be attributed to the telephone intervention. Thirty-five percent of patients contacted by telephone reported receiving influenza immunization at a site other than the Family Practice Center. CONCLUSIONS: The postcard intervention was associated with a significant increase in the office immunization rate. This increase may have been confounded by "site shift" in which individuals came to the office for an immunization that they might otherwise have received at other community sites.     

Postcard reminders from GPs for influenza vaccine: Are they more effective than an ad hoc approach?

All persons 65 years and older are recommended to be immunised against influenza each autumn. As immunisation rates remain low, we conducted a randomised control trial in a three-partner urban general practice to evaluate the differential effectiveness of a single postcard reminder in a general practice setting compared to usual care. All non-residential patients aged 65 years and over were identified from the age/sex/disease register. After exclusions, 325 patients were stratified by sex (125 men and 200 women) and randomised to receive either a postcard reminder in large print mailed in April or usual care. General practitioners (GPs) were blind to the randomisation. A blinded record audit performed in July demonstrated that the postcard was effective in increasing immunisation for men (X²_1df=3.85; p=0.05) but not for women (X²_1df=0.45; p=0.50). After adjusting for 1995 immunisation status, the effect of the postcard on immunisation rates was even stronger in men (Wald X²_1df=6.20; p=0.01) but remained non-significant in women (Wald x²_1df=1.38; p=0.24). With this adjustment, the odds of having the 1996 flu vaccine for men sent the postcard reminder were three times that of men in the control group (OR=3.0; 95% Cl 1.3–6.9). In a general practice setting, a single postcard reminder appears to be a promising way to boost influenza immunisation rates among ageing men. Replication of the study is recommended.     

Public health in managed care: a randomized controlled trial of the effectiveness of postcard reminders.

OBJECTIVES: This study evaluated the effectiveness of an annual public health intervention in a managed care setting. METHODS: Managed care organization members 65 years and older who received influenza immunization in 1996 were randomized to an intervention group (mailed a postcard reminder to receive an influenza vaccination in 1997) or a control group (no postcard). Vaccination rates for both groups were assessed monthly. RESULTS: Members receiving the intervention were no more likely to be immunized (78.6%) than members of the control group (77.2%, P = .222). Members were vaccinated at the same pace regardless of vaccination history and postcard intervention status. CONCLUSIONS: Postcard reminders were not an effective intervention among seniors who had been vaccinated the previous year.     

Vaccination of high-risk patients for influenza. A comparison of telephone and mail reminder methods

During the 1984-1985 influenza season two study groups were used to compare telephone and letter reminder methods with a control group that received no reminder to determine which was the most effective strategy to increase influenza vaccination rates among the high-risk patient population of a university-based family practice. Seven hundred eighty-seven high-risk patients were randomly assigned to one of the three study groups: a mailed-reminder group, a telephone-reminder group, and a control group. Vaccination rates for both reminder methods were significantly higher than for the control group (P less than .02), and if successfully contacted, the telephone-reminder group had a significantly better vaccination rate than the mailed-reminder group (P less than .05). If successful telephone contact can be made, this reminder method is more effective than a letter reminder to increase influenza vaccination rates among high-risk patients.     

Introductory postcards: do they increase response rate in a telephone survey of older persons?

The purpose of this study was to assess whether contact by mail via an introductory postcard would increase the response rate to a telephone survey in a selected population of 348 people 60 years and older. Of this group, 208 were sent a postcard introducing the study and informing them that someone would call in the next 1-2 weeks to conduct a telephone interview. The remaining sample of 140 did not receive the introductory postcard. Amongst the potential participants who were contacted and able to participate (n = 240), the response rate for completed interview was 58.0% for those sent a postcard and 42.3% for those who were not. The refusal rate was 25.3% (postcard sent) and 37.2% (not sent a postcard). When the outcome of contact is collapsed to two categories, 'agreed to participate' and 'refusal', the response rate to participate was 73.5% (sent a postcard) and 59.0% (not sent a postcard) (chi(2) 5.14, d.f. 1, sign. 0.023). The response rate amongst those who recall being sent a postcard rose to 86.0%. Whether agreeing to participate or refusing to be involved in the survey was dependent on being sent an introductory postcard. The conclusion is that mailing a postcard prior to the first telephone contact increases the participation rates of older persons in a telephone survey at very little extra cost (A$0.60 per person).     

Estimation of outpatient risk characteristics and influenza vaccination status: validation of a self-administered questionnaire.

As part of an effort to evaluate the effectiveness of a multifaceted, institution-wide influenza vaccination program, we mailed a self-administered postcard questionnaire to 500 randomly selected outpatients following both the 1987-1988 and 1988-1989 immunization seasons. The postcard asked if the patients received influenza vaccine, where they were immunized, whether they had any high-risk medical illnesses, their age at their last birthday, and their name. To assess the validity of the questionnaire, following the 1988 survey, we selected a 25% systematic sample of respondents and compared survey responses with medical record documentation. Response rates for the surveys were 77.6% for the 1988 survey (two mailings) and 86.5% for the 1989 survey (three mailings). Ninety-four percent (n = 89) of charts selected for audit were successfully reviewed. Agreement between questionnaire responses and medical records was excellent, with greater than 90% agreement and kappas of .8 to .9 for classifying patients as high-risk and receipt of vaccine at the Department of Veterans' Affairs Medical Center. For other data, agreement ranged from 84% to 96% with kappas of .6 to .75. Responses to the 1989 survey also demonstrated the importance of sample frame definition and response wave on estimates of risk characteristics and vaccination rates. A self-administered postcard questionnaire is a valid tool for estimating outpatient risk characteristics and influenza vaccination rates.     

Impact of a postcard versus a questionnaire as a first reminder in a postal lifestyle survey.

STUDY OBJECTIVE--The study aimed to consider the impact of two different types of reminder on response rates and costs in a postal survey. DESIGN--The study was a cross sectional survey. A self-completion lifestyle questionnaire was used. Those who did not respond after the initial mailing were randomly allocated to receive either a postcard or questionnaire as a first reminder. All outstanding non-responders received a questionnaire as a second reminder. SUBJECTS--A representative sample of 698 adults aged 16-70 was used, drawn from a family health services authority register. MAIN RESULTS--Postcard reminders were as effective as questionnaire reminders in increasing response whether one or two reminders are sent. The costs per response were calculated. Two questionnaires as reminders were found to be 1.7 times more expensive than a postcard plus questionnaire. Including the initial mailing, the cost per response using all questionnaires was 1.3 times the cost when a postcard was used for the first reminder. CONCLUSIONS--To increase the response to a postal survey effectively and economically, two reminders should be sent--first a postcard and then a questionnaire.     

Effect of mobile phone text messaging for improving the uptake of influenza vaccination in patients with rare diseases

ObjectivesInfluenza vaccine is recommended in some chronic medical conditions, including several rare diseases. The objectives of the study were to assess the effect of text message reminders on influenza vaccination uptake of patients with selected rare diseases and delayed vaccination, and to describe their characteristics.MethodsQuasi-experimental pre-post intervention study performed along the 2016 influenza vaccination campaign in the Autonomous Community of Madrid. Unvaccinated patients diagnosed with a selected rare disease were targeted for intervention. SMS were sent to them at least one month after the beginning of the campaign, in four consecutive weeks. Those with no mobile phones available or no certainty of message reception, were assigned as controls. The association between the reception of the SMS and vaccination uptake was assessed using multiple poisson regression models.ResultsOf 69.040 patients with delayed vaccination, 87.2% received an SMS reminder in the asigned contact mobile telephone. Global influenza vaccine coverage reached 41.3%. The uptake of influenza vaccine was significantly higher among those receiving the reminder (9.3% vs. 7.1% in the control group, p < 0.001). Those who received a SMS reminder were 30% more likely to uptake seasonal influenza vaccine. By sex and age, the reception of the reminder was associated with a significantly higher probability of vaccination in men ≥65 years with at least a concurrent chronic condition (IRR: 1.58, CI95%: 1.25–2.00). Among women, this higher probability was detected in those between 14 and 64 years of age (IRR: 1.41, CI95%: 1.22–1.63), and ≥65 years without concurrent chronic conditions (IRR: 1.40, CI95%: 1.05–1.89).ConclusionAlthough the intervention was modestly effective, it proved beneficial in some cases. It can be an additional strategy to improve vaccine uptake, since it is simple, feasible, affordable and easily scalable, particularly when immunization and target population data are available in population registries.     

Influenza vaccine uptake and distribution in England and Wales using data from the General Practice Research Database, 1989/90-2003/04

BACKGROUND: Routinely collected data from patients registered with general practices participating in the General Practice Research Database (GPRD) were used to analyse influenza vaccine uptake and distribution in England and Wales between 1989/90 and 1996/97. Major changes to influenza immunization policy were introduced in 1998 and 2000 when immunization of the elderly became age related rather than risk related. This new study examines trends in vaccine uptake for high- and low-risk patients and the impact of the policy changes on uptake in the elderly. METHODS: Between 0.5 and 2.7 million patients registered with practices participating in the GPRD from 1989 to 2004 were included. Data were examined by age group, medical risk group and evidence of vaccination per study year. RESULTS: Vaccine uptake among high-risk persons aged 65 or more increased from 36.7 per cent in 1989/90 to 72.1 per cent in 2003/04. For the same period, uptake rates for high-risk persons under 65 years increased from 10.8 to 24.3 per cent. For those at high risk, uptake by females was higher in all age groups up to 65 years. Of those that were vaccinated, a higher proportion of the 65 and over were vaccinated in October each year compared with the high risk under 65 (p < 0.001). CONCLUSIONS: Coverage among high-risk patients in younger age groups continues to fall well below satisfactory levels, especially among the youngest groups. Government policy should now focus on ways to improve uptake in these patients.     

Do incentives, reminders or reduced burden improve healthcare professional response rates in postal questionnaires? two randomised controlled trials

ABSTRACT: BACKGROUND: Healthcare professional response rates to postal questionnaires are declining and this may threaten the validity and generalisability of their findings. Methods to improve response rates do incur costs (resources) and increase the cost of research projects. The aim of these randomised controlled trials (RCTs) was to assess whether 1) incentives, 2) type of reminder and/or 3) reduced response burden improve response rates; and to assess the cost implications of such additional effective interventions. METHODS: Two RCTs were conducted. In RCT A general dental practitioners (dentists) in Scotland were randomised to receive either an incentive; an abridged questionnaire or a full length questionnaire. In RCT B non-responders to a postal questionnaire sent to general medical practitioners (GPs) in the UK were firstly randomised to receive a second full length questionnaire as a reminder or a postcard reminder. Continued non-responders from RCT B were then randomised within their first randomisation to receive a third full length or an abridged questionnaire reminder. The cost-effectiveness of interventions that effectively increased response rates was assessed as a secondary outcome. RESULTS: There was no evidence that an incentive (52% versus 43%, Risk Difference (RD) -8.8 (95%CI [MINUS SIGN]22.5, 4.8); or abridged questionnaire (46% versus 43%, RD [MINUS SIGN]2.9 (95%CI [MINUS SIGN]16.5, 10.7); statistically significantly improved dentist response rates compared to a full length questionnaire in RCT A. In RCT B there was no evidence that a full questionnaire reminder statistically significantly improved response rates compared to a postcard reminder (10.4% versus 7.3%, RD 3 (95%CI [MINUS SIGN]0.1, 6.8). At a second reminder stage, GPs sent the abridged questionnaire responded more often (14.8% versus 7.2%, RD [MINUS SIGN]7.7 (95%CI [MINUS SIGN]12.8, -2.6). GPs who received a postcard reminder followed by an abridged questionnaire were most likely to respond (19.8% versus 6.3%, RD 8.1%, and 9.1% for full/postcard/full, three full or full/full/abridged questionnaire respectively). An abridged questionnaire containing fewer questions following a postcard reminder was the only cost-effective strategy for increasing the response rate ([POUND SIGN]15.99 per response). CONCLUSIONS: When expecting or facing a low response rate to postal questionnaires, researchers should carefully identify the most efficient way to boost their response rate. In these studies, an abridged questionnaire containing fewer questions following a postcard reminder was the only cost-effective strategy. An increase in response rates may be explained by a combination of the number and type of contacts. Increasing the sampling frame may be more cost-effective than interventions to prompt non-responders. However, this may not strengthen the validity and generalisability of the survey findings and affect the representativeness of the sample.     

Inequalities in uptake of influenza vaccine by deprivation and risk group: time trends analysis

The aim of this study was to investigate influenza immunisation rates in the United Kingdom over a 6-year period and examine trends in uptake by deprivation, ethnicity, rurality and risk group. Influenza immunisation rates were determined from 1999/2000 to 2004/2005 using a large general practice database (QRESEARCH). There was a relative increase of 59.5% in the overall influenza vaccination rate over the study period. In 2004/2005, 70.2% of all patients aged 65 and over were vaccinated, compared with 29.3% of patients in a clinical risk group aged less than 65. Males, patients from deprived areas and from areas with a higher proportion of non-White residents had slightly lower vaccination rates overall. This general practice based study suggests that substantial increases in influenza vaccination rates have occurred across all risk groups, but that increased focus should be given to immunising high-risk patients below the age of 65.     

Influenza vaccine effectiveness among patients with high-risk medical conditions in the United States, 2012–2016

BackgroundAnnual influenza vaccination has been recommended for persons with high-risk conditions since the 1960s. However, few estimates of influenza vaccine effectiveness (VE) for persons with high-risk conditions are available.MethodsData from the U.S. Influenza Vaccine Effectiveness Network from 2012 to 2016 were analyzed to compare VE of standard-dose inactivated vaccines against medically-attended influenza among patients aged ≥6 months with and without high-risk medical conditions. Patients with acute respiratory illness were tested for influenza by RT-PCR. Presence of high-risk conditions and vaccination status were obtained from medical records. VE by influenza virus type/subtype and age group was calculated for patients with and without high-risk conditions using the test-negative design. Interaction terms were used to test for differences in VE by high-risk conditions.ResultsOverall, 9643 (38%) of 25,369 patients enrolled during four influenza seasons had high-risk conditions; 2213 (23%) tested positive for influenza infection. For all ages, VE against any influenza was lower among patients with high-risk conditions (41%, 95% CI: 35–47%) than those without (48%, 95% CI: 43–52%; P-for-interaction = 0.02). For children aged <18 years, VE against any influenza was 51% (95% CI: 39–61%) and 52% (95% CI: 39–61%) among those with and without high-risk conditions, respectively (P-for-interaction = 0.54). For adults aged ≥18 years, VE against any influenza was 38% (95% CI: 30–45%) and 44% (95% CI: 38–50%) among those with and without high-risk conditions, respectively (P-for-interaction = 0.21). For both children aged <18 and adults aged ≥18 years, VEs against illness related to influenza A(H3N2), A(H1N1)pdm09, and influenza B virus infection were similar among those with and without high-risk conditions.ConclusionsInfluenza vaccination provided protection against medically-attended influenza among patients with high-risk conditions, at levels approaching those observed among patients without high-risk conditions. Results from our analysis support recommendations of annual vaccination for patients with high-risk conditions.     

The effect of a combined influenza/pneumococcal immunization reminder letter

BACKGROUND: The effect of a combined influenza and pneumococcal immunization reminder letter on increasing influenza and pneumococcal immunization rates, and the timeliness of receiving immunizations after receipt of a reminder letter, have not been examined. This study addresses these issues using a sample of new Medicare beneficiaries residing in Hawaii. METHODS: Newly enrolled Medicare beneficiaries in Hawaii from 25 September 1995 through 31 August 1996 were randomly assigned to one of three groups: Group 1, no letter (n=2144); Group 2, influenza immunization reminder letter only (n=2213); or Group 3, pneumococcal and influenza immunization reminder letter (n=2171). Health Care Financing Administration claims data were compared among groups. RESULTS: In Group 3, the influenza immunization rate increased 3.8 percentage points (n=87; p=0.017) compared with Group 1. The Group 3 pneumococcal immunization rate increased 3.5 percentage points (n=78; p<0.001) compared to Group 1 and 4.0 percentage points (n=86; p<0.001) compared to Group 2. Sixty-six beneficiaries in Group 3 received simultaneous pneumococcal and influenza immunizations, a significant difference compared to Group 1 or Group 2. Increases in immunizations were observed immediately following the reminder letters and the effect persisted for 5 to 7 weeks. CONCLUSIONS: The combination letter increased both influenza and pneumococcal immunization rates and the simultaneous administration of immunizations without detrimental effect to influenza immunization rates. A combined reminder letter is inexpensive and recommended as part of a multicomponent campaign for adult immunization.     

Assessing delivery practices of mothers over time and over space in Uganda, 2003–2012

The issue of poor response rates to population surveys has existed for some decades, but few studies have explored methods to improve the response rate in follow-up population cohort studies. A sample of 100,000 adults from the 45 and Up Study, a large population cohort in Australia, were followed up 3.5 years after the baseline cohort was assembled. A pilot mail-out of 5000 surveys produced a response rate of only 41.7 %. This study tested methods of enhancing response rate, with three groups of 1000 each allocated to (1) receiving an advance notice postcard followed by a questionnaire, (2) receiving a questionnaire and then follow-up reminder letter, and (3) both these strategies. The enhanced strategies all produced an improved response rate compared to the pilot, with a resulting mean response rate of 53.7 %. Highest response was found when both the postcard and questionnaire reminder were used (56.4 %) but this was only significantly higher when compared to postcard alone (50.5 %) but not reminder alone (54.1 %). The combined approach was used for recruitment among the remaining 92,000 participants, with a resultant further increased response rate of 61.6 %. Survey prompting with a postcard and a reminder follow-up questionnaire, applied separately or combined can enhance follow-up rates in large scale survey-based epidemiological studies.     

Tailored interventions to increase influenza vaccination in neighborhood health centers serving the disadvantaged

OBJECTIVES: We designed and evaluated interventions to increase adult immunizations within inner-city health centers. METHODS: Interventions included reminders, standing orders, and walk-in "flu shot clinics." Patients were surveyed and records evaluated. RESULTS: Records from 1 center showed that immunization rates increased from 24% to 30% (P <.001) for patients aged 50 to 64 years and from 45% to 53% for patients aged 65 years and older (P <.001). Self-reported vaccination rates did not increase. In logistic regression analyses, the strongest predictor of vaccination among patients aged 50 to 64 years was the belief that unvaccinated persons will contract influenza (odds ratio [OR] = 5.4; 95% confidence interval [CI] = 2.4, 12.0). Among patients aged 65 years and older, the strongest predictor of vaccination was the belief that friends/relatives thought that they should be vaccinated (OR = 9.7; 95% CI = 4.2, 22.3). CONCLUSIONS: Tailored interventions can improve immunization rates at inner-city health centers.     

Telephone reminders increase re-screening in a county breast screening program

INTRODUCTION: Mammography can reduce breast cancer mortality through routine screening. We tested an intervention to increase re-screening in a county program. METHODS: The program requires enrollment before screening. We randomized women who had previously been screened by the program to a telephone call reminder for re-enrollment or usual care (postcard reminder). We followed re-enrollment and re-screening rates for both groups. RESULTS: Compared with the control group (n=610), women in the intervention group (n=599) had higher rates of initial re-enrollment at one month (10% vs. 24%, p<.001) and re-screening at two months (11% vs. 19%, p<.001). These effects persisted over time (five-month re-enrollment: 24% vs. 35%, p<.001; six-month re-screening: 23% vs. 31%, p=.004). The intervention did not alter the odds of a woman's being re-screened once re-enrolled. CONCLUSION: The increase in our re-screening rate after this simple intervention was as great or greater than the rates reported in other studies. A telephone reminder for women previously enrolled in a county breast screening program can increase re-enrollment and subsequent re-screening rates.     

Provider attitudes regarding use of an immunization information system to identify children with asthma for influenza vaccination.

OBJECTIVES: Despite longstanding national guidelines, many children with asthma do not receive annual influenza vaccinations. Information from Medicaid-administrative claims data was integrated into the Michigan Care Improvement Registry (MCIR) to prompt providers regarding influenza vaccination among children with high-risk conditions such as asthma. The attitudes of pediatric primary care providers regarding the implementation of this system were assessed. METHODS: A survey was sent in February 2006 to office-based general pediatricians (n = 300) and family physicians (n = 300) in Michigan. The survey focused on influenza vaccination during the 2005-2006 influenza season and attitudes regarding a reminder system for providers using the MCIR. RESULTS: Overall response rate was 67 percent. MCIR participation was high (91%) among respondents, and most (83%) had MCIR information available to them prior to visits with pediatric patients. Most physicians (75%) considered the MCIR high-risk indicator for influenza vaccination a feature that they would find helpful. Some respondents reported concerns that the reminder system is limited to Medicaid patients only (44%) and regarding the completeness of Medicaid data to identify children with asthma (24%). CONCLUSIONS: Physicians have a positive overall view of a statewide registry-based automated reminder system to assist in identifying children with asthma for influenza vaccination, albeit with specific areas of concern.     

Reminder cards and immunization rates among Latinos and the rural poor in Northeast Colorado.

OBJECTIVE: Immunization rates are static in the United States. Risk factors for not being up to date (UTD) include ethnicity and lower socioeconomic status. Reminder cards increase immunization rates in urban settings. Their effect in poor, Latino, and rural children is unknown. BACKGROUND: Language-appropriate reminder cards were sent to active patients not UTD listing the vaccines missing; the card served as the physician order for the vaccine. Missed opportunities were addressed through discussion with staff and posters in patient care rooms. UTD rates before and after intervention were measured. RESULTS: Dual-purpose reminder/order cards increased the rate of UTD from 61.3% to 73.4%; children living near the clinic, patients who speak only Spanish, and Latinos overall showed preferential effectiveness. Children eligible to participate in the Vaccines for Children program had similar increases in UTD rates but had lower baseline and final UTD rates than did children not eligible for the Vaccines for Children program. The rate of missed opportunities did not change. The number of children to whom reminder cards needed to be sent for them to become fully immunized is 8 (number needed to treat). CONCLUSIONS: In poor, rural, and Latino populations, language-appropriate reminder/order cards increase immunization rates.