Immunization pockets of need: science and practice

The Challenge of Achieving Immunity Through Multiple-Dose Vaccines in Madagascar

Administration of many childhood vaccines requires that multiple doses be delivered within a narrow time window to provide adequate protection and reduce disease transmission. Accurately quantifying vaccination coverage is complicated by limited individual-level data and multiple vaccination mechanisms (routine and supplementary vaccination programs). We analyzed 12,541 vaccination cards from 6 districts across Madagascar for children born in 2015 and 2016. For 3 vaccines-pentavalent diphtheria-tetanus-pertussis-hepatitis B-Haemophilus influenzae type b vaccine (DTP-HB-Hib; 3 doses), 10-valent pneumococcal conjugate vaccine (PCV10; 3 doses), and rotavirus vaccine (2 doses)-we used dates of vaccination and birth to estimate coverage at 1 year of age and timeliness of delivery. Vaccination coverage at age 1 year for the first dose was consistently high, with decreases for subsequent doses (DTP-HB-Hib: 91%, 81%, and 72%; PCV10: 82%, 74%, and 64%; rotavirus: 73% and 63%). Coverage levels between urban districts and their rural counterparts did not differ consistently. For each dose of DTP-HB-Hib, the overall percentage of individuals receiving late doses was 29%, 7%, and 6%, respectively; estimates were similar for other vaccines. Supplementary vaccination weeks, held to help children who had missed routine care to catch up, did not appear to increase the likelihood of being vaccinated. Maintaining population-level immunity with multiple-dose vaccines requires a robust stand-alone routine immunization program.

An Evaluation of Voluntary Varicella Vaccination Coverage in Zhejiang Province, East China

Background: In 2014 a 2-doses varicella vaccine (VarV) schedule was recommended by the Zhejiang Provincial Center for Disease Control and Prevention. We aimed to assess the coverage of the 1st dose of VarV (VarV₁) and the 2nd dose of VarV (VarV₂) among children aged 2–6 years through the Zhejiang Provincial Immunization Information System (ZJIIS) and to explore the determinants associated with the VarV coverage. Methods: Children aged 2–6 years (born from 1 January 2009 to 31 December 2013) registered in ZJIIS were enrolled. Anonymized individual records of target children were extracted from the ZJIIS database on 1 January 2016, including their VarV and (measles-containing vaccine) MCV vaccination information. The VarV₁ and VarV₂ coverage rates were evaluated for each birth cohorts. The coverage of VarV also was estimated among strata defined by cities, gender and immigration status. We also evaluated the difference in coverage between VarV and MCV. Results: A total of 3,028,222 children aged 2–6 years were enrolled. The coverage of VarV₁ ranged from 84.8% to 87.9% in the 2009–2013 birth cohorts, while the coverage of VarV₂ increased from 31.8% for the 2009 birth cohort to 48.7% for the 2011 birth cohort. Higher coverage rates for both VarV₁ and VarV₂ were observed among resident children in relevant birth cohorts. The coverage rates of VarV₁ and VarV₂ were lower than those for the 1st and 2nd dose of MCV, which were above 95%. The proportion of children who were vaccinated with VarV₁ at the recommended age increased from 34.6% for the 2009 birth cohort to 75.2% for the 2013 birth cohort, while the proportion of children who were vaccinated with VarV₂ at the recommended age increased from 19.7% for the 2009 birth cohort to 48.7% for the 2011 birth cohort. Conclusions: Our study showed a rapid increasing VarV₂ coverage of children, indicating a growing acceptance of the 2-doses VarV schedule among children’s caregivers and physicians after the new recommendation released. We highlighted the necessity for a 2-doses VarV vaccination school-entry requirement to achieve the high coverage of >90% and to eliminate disparities in coverage among sub-populations. We also recommended continuous monitoring of the VarV coverage via ZJIIS over time.

Fully immunized child: coverage, timing and sequencing of routine immunization in an urban poor settlement in Nairobi, Kenya

BACKGROUND

More efforts have been put in place to increase full immunization coverage rates in the last decade. Little is known about the levels and consequences of delaying or vaccinating children in different schedules. Vaccine effectiveness depends on the timing of its administration, and it is not optimal if given early, delayed or not given as recommended. Evidence of non-specific effects of vaccines is well documented and could be linked to timing and sequencing of immunization. This paper documents the levels of coverage, timing and sequencing of routine childhood vaccines.

METHODS

The study was conducted between 2007 and 2014 in two informal urban settlements in Nairobi. A total of 3856 children, aged 12-23 months and having a vaccination card seen were included in analysis. Vaccination dates recorded from the cards seen were used to define full immunization coverage, timeliness and sequencing. Proportions, medians and Kaplan-Meier curves were used to assess and describe the levels of full immunization coverage, vaccination delays and sequencing.

RESULTS

The findings indicate that 67 % of the children were fully immunized by 12 months of age. Missing measles and third doses of polio and pentavalent vaccine were the main reason for not being fully immunized. Delays were highest for third doses of polio and pentavalent and measles. About 22 % of fully immunized children had vaccines in an out-of-sequence manner with 18 % not receiving pentavalent together with polio vaccine as recommended.

CONCLUSIONS

Results show higher levels of missed opportunities and low coverage of routine childhood vaccinations given at later ages. New strategies are needed to enable health care providers and parents/guardians to work together to increase the levels of completion of all required vaccinations. In particular, more focus is needed on vaccines given in multiple doses (polio, pentavalent and pneumococcal conjugate vaccines).

Overcoming Challenges to Childhood Immunizations Status

Vaccines are one of the greatest public health achievements, preventing both mortality and morbidity. However, overall immunization rates are still below the 90% target for Healthy People 2020. There remain significant disparities in immunization rates between children of different racial/ethnic groups, as well as among economically disadvantaged populations. There are systemic issues and challenges in providing access to immunization opportunities. In addition, vaccine hesitancy contributes to underimmunization. Multiple strategies are needed to improve immunization rates, including improving access to vaccines and minimizing financial barriers to families. Vaccine status should be assessed and vaccines given at all possible opportunities.

A current and historical perspective on disparities in US childhood pneumococcal conjugate vaccine adherence and in rates of invasive pneumococcal disease: Considerations for the routinely-recommended, pediatric PCV dosing schedule in the United States

Previous research has suggested that reducing the US 4-dose PCV13 schedule to a 3-dose schedule may provide cost savings, despite more childhood pneumococcal disease. The study also stressed that dose reduction should be coupled with improved PCV adherence, however, US PCV uptake has leveled-off since 2008. An estimated 24–36% of US children aged 5–19 months are already receiving a reduced PCV schedule (i.e., missing ≥1 dose). This raises a practical concern that, under a reduced, 3-dose schedule, a similar proportion of children may receive ≤2 doses. It is also unknown if a reduced, 3-dose PCV schedule in the United States will afford the same disease protection as 3-dose schedules used elsewhere, given lower US PCV adherence. Finally, more assurance is needed that, under a reduced schedule, racial, socioeconomic, and geographic disparities in PCV adherence will not correspond with disproportionately higher rates of pneumococcal disease among poor or minority children.

Improving school immunization rates may be as basic as record reconciliation and policy enforcement: a report from a rural Colorado public health/school district initiative

The aim of this report was to assess the coverage rate of required immunizations for kindergarten-12 students in the Eagle County School District and to create a process for annual, district-wide immunization assessments to inform immunization campaigns. All kindergarten-12 student records were reviewed, and immunization rates during the 2012-2014 years were compiled. At baseline, only 2096 (34%) were in compliance with the Colorado School Immunization Law. After reconciliation of records and instituting a recall system in year 1 and enforcement of the Colorado School Immunization Law suspension rule in year 2, a total of 5862 (98.8%; P < .001) students were in compliance. Immunization rates for Eagle County School District students were unknown due to the lack of a process to assess a compliance rate and the lack of reconciliation of records. Although initially time-intensive, the project has impacted the community through the creation of a sustainable process of collecting and reporting student immunization records through a centralized state immunization registry.

An evaluation of voluntary 2-dose varicella vaccination coverage in New York City public schools

OBJECTIVES

We assessed coverage for 2-dose varicella vaccination, which is not required for school entry, among New York City public school students and examined characteristics associated with receipt of 2 doses.

METHODS

We measured receipt of either at least 1 or 2 doses of varicella vaccine among students aged 4 years and older in a sample of 336 public schools (n = 223 864 students) during the 2010 to 2011 school year. Data came from merged student vaccination records from 2 administrative data systems. We conducted multivariable regression to assess associations of age, gender, race/ethnicity, and school location with 2-dose prevalence.

RESULTS

Coverage with at least 1 varicella dose was 96.2% (95% confidence interval [CI] = 96.2%, 96.3%); coverage with at least 2 doses was 64.8% (95% CI = 64.6%, 64.9%). Increasing student age, non-Hispanic White race/ethnicity, and attendance at school in Staten Island were associated with lower 2-dose coverage.

CONCLUSIONS

A 2-dose varicella vaccine requirement for school entry would likely improve 2-dose coverage, eliminate coverage disparities, and prevent disease.

To give or not to give: Approaches to early childhood immunization delivery in Oregon rural primary care practices

CONTEXT

Little is known about rural clinicians' perspectives regarding early childhood immunization delivery, their adherence to recommended best immunization practices, or the specific barriers they confront.

PURPOSE

To examine immunization practices, beliefs, and barriers among rural primary care clinicians for children in Oregon and compare those who deliver all recommended immunizations in their practices with those who do not.

METHODS

A mailed questionnaire was sent to all physicians, nurse practitioners, and physician assistants practicing primary care in rural communities throughout Oregon.

FINDINGS

While 39% of rural clinicians reported delivering all childhood immunizations in their clinic, 43% of clinicians reported that they refer patients elsewhere for some vaccinations, and 18% provided no immunizations in the clinic whatsoever. Leading reasons for referral include inadequate reimbursement, parental request, and storage and stocking difficulties. Nearly a third of respondents reported that they had some level of concern about the safety of immunizations, and 14% reported that concerns about safety were a specific reason for referring. Clinicians who delivered only some of the recommended immunizations were less likely than nonreferring clinicians to have adopted evidence-based best immunization practices.

CONCLUSIONS

This study of rural clinicians in Oregon demonstrates the prevalence of barriers to primary care based immunization delivery in rural regions. While some barriers may be difficult to overcome, others may be amenable to educational outreach and support. Thus, efforts to improve population immunization rates should focus on promoting immunization "best practices" and enhancing the capacity of practices to provide immunizations and ensuring that any alternative means of delivering immunizations are effective.

Related factors of age-appropriate immunization among urban-rural children aged 24-35 months in a 2005 population-based survey in Nonsan, Korea

PURPOSE

This study was aimed to determine the status and related factors of age-appropriate immunization among urban-rural children aged 24-35 months in a 2005 population-based survey in Nonsan, Korea.

MATERIALS AND METHODS

We conducted household survey and provider check using questionnaire and checklist to obtain data on immunization status for children, aged 24-35 months. Age-appropriate immunization was defined as status of receiving the fourth diphtheria-tetanus-pertussis (4 DTP), 3 Polio, the first measles-mumps-rubella (1 MMR) doses, and the 4 : 3 : 1 series.

RESULTS

Age-appropriate immunization rates were 51.7% for 4 DPT, 88.0% for 3 Polio, 87.9% for 1 MMR, and 50.3% for the 4 : 3 : 1 series. First-born children, lower perceived barrier scores, and higher perception of immunization data were significantly related to age-appropriate immunization.

CONCLUSION

The findings indicated that age-appropriate immunization rate could be improved by implementing reminder/recall service and providing the knowledge about immunization. Identification and consideration related factors would improve immunization rate and age-appropriate immunization.

A stepped intervention increases well-child care and immunization rates in a disadvantaged population

OBJECTIVE

To test a stepped intervention of reminder/recall/case management to increase infant well-child visits and immunization rates.

METHODS

We conducted a randomized, controlled, practical, clinical trial with 811 infants born in an urban safety-net hospital and followed through 15 months of life. Step 1 (all infants) involved language-appropriate reminder postcards for every well-child visit. Step 2 (infants who missed an appointment or immunization) involved telephone reminders plus postcard and telephone recall. Step 3 (infants still behind on preventive care after steps 1 and 2) involved intensive case management and home visitation.

RESULTS

Infants in the intervention arm, compared with control infants, had significantly fewer days without immunization coverage in the first 15 months of life (109 vs 192 days P < .01) and were more likely to have >or=5 well-child visits (65% vs 47% P < .01). In multivariate analyses, infants in the intervention arm were more likely than control infants to be up to date with 12-month immunizations and to have had >or=5 well-child visits. The cost per child was $23.30 per month.

CONCLUSION

This stepped intervention of tracking and case management improved infant immunization status and receipt of preventive care in a population of high-risk urban infants of low socioeconomic status.

Adolescent immunizations: missed opportunities for prevention

OBJECTIVES

The goals were (1) to describe immunization rates for tetanus-diphtheria, hepatitis B, and measles-mumps-rubella vaccines among 13-year-old adolescents; (2) to identify missed opportunities for tetanus-diphtheria immunization among adolescents 11 to 17 years of age; and (3) to evaluate the association between preventive care use and tetanus-diphtheria immunization.

METHODS

Adolescents born between January 1, 1986, and December 31, 1991, and enrolled in Harvard Pilgrim Health Care and Harvard Vanguard Medical Associates for >or=1 year in 1997-2004 were included. Immunization rates for tetanus-diphtheria, hepatitis B, and measles-mumps-rubella were assessed at 13 years of age. Missed opportunities for tetanus-diphtheria immunization within 14 days after a health care visit were measured. Multivariate models were used to determine predictors of timeliness of tetanus-diphtheria vaccination, particularly the use of preventive care services. RESULTS. A total of 23,987 eligible adolescents were enrolled in Harvard Pilgrim Health Care and Harvard Vanguard Medical Associates between 1997 and 2004. Among 13-year-old adolescents in the most recent birth cohort, 84%, 74%, and 67% were up to date for tetanus-diphtheria, hepatitis B, and measles-mumps-rubella, respectively. When the analysis was limited to those with >or=1 vaccine received before 2 years of age (a proxy measure for complete records), 92%, 82%, and 85% were up to date for tetanus-diphtheria, hepatitis B, and measles-mumps-rubella, respectively. Missed opportunities for tetanus-diphtheria immunization occurred at 84% of all health care visits. Adolescents who did not seek preventive care were less likely to receive tetanus-diphtheria in a timely manner.

CONCLUSIONS

Adolescent immunization rates lag far behind childhood rates, and missed opportunities are common. Additional strategies are needed to increase the use of preventive services among adolescents and to enable providers to vaccinate adolescents at every opportunity.

How effectively can health care settings beyond the traditional medical home provide vaccines to adolescents?

OBJECTIVES

Our goal was to evaluate the capacity of various health care settings to supplement the activities of the traditional medical home by delivering vaccines to adolescents.

METHODS

A group of experts in the fields of adolescent-immunization delivery and the provision of preventive care in various health care settings summarized the available literature, considered setting-specific factors, and assessed the ability of various health care settings beyond the traditional medical home to conform to the immunization quality standards set by the National Vaccine Advisory Committee, report vaccination information for the quantitative assessment of vaccine-coverage rates, be likely to offer vaccines to adolescents, and be viewed by adolescents as acceptable sites for receiving vaccinations.

RESULTS

Seven candidate settings were evaluated: pharmacies, obstetrics-gynecology practices, sexually transmitted disease clinics, hospital emergency departments, family planning clinics, teen clinics, and local public health department immunization clinics. The panel concluded that all could safely provide vaccinations to adolescents but that vaccination efforts at some of the settings could potentially have a markedly greater impact on overall adolescent-immunization rates than could those at other settings. In addition, for adolescent-vaccination services to be practical, candidate settings need to have a clear interest in providing them. Conditional on that, several issues need to be addressed: (1) funding; (2) orienting facilities to provide preventive care services; (3) enhancing access to immunization registries; and (4) clarifying issues related to immunization consent.

CONCLUSIONS

With supporting health policy, health education, and communication, health care settings beyond the traditional medical home have the potential to effectively augment the vaccination efforts of more traditional settings to deliver vaccines to adolescents. These health care settings may be particularly well suited to reach adolescents who lack access to traditional sources of preventive medical care or receive fragmented medical care.

Combining evidence and diffusion of innovation theory to enhance influenza immunization

BACKGROUND

Children and adolescents with chronic conditions such as asthma, diabetes, and HIV are at high risk of influenza-related morbidity, and there are recommendations to immunize these populations annually. At Cincinnati Children's Hospital Medical Center, the influenza immunization rate increased to 90.4% (5% declined) among 200 patients with cystic fibrosis (CF). Diffusion of innovation theory was used to guide the design and implementation of spread to other clinics.

METHOD

The main intervention strategies were: (1) engagement of interested, nurse-led teams, (2) A collaborative learning session, (3) A tool kit including literature, sample goals, reminder postcards, communication strategies, and team member roles and processes, (4) open-access scheduling and standing orders (5) A simple Web-based registry, (6) facilitated vaccine ordering, (7) recall phone calls, and (8) weekly results posting.

RESULTS

Clinic-specific immunization rates ranged from 32.7% to 92.8%, with the highest rate reported in the CF clinic. All teams used multiple strategies; with six of the seven using four or more. Overall, 60.0% (762/1,269) of the population was immunized. Barriers included vaccine shortages, lack of time for reminder calls, and lack of physician support in one clinic.

DISCUSSION

A combination of interventions, guided by evidence and diffusion of innovation theory, led to immunization rates higher than those reported in the literature.

The impact of inactive infants on clinic-based immunization rates

OBJECTIVE

Clinic-based immunization rates are used to evaluate clinic performance and immunization interventions, but they typically exclude so-called inactive patients (ie, those who no longer receive care at the clinic). We assessed the effect of enhanced ascertainment of inactive patients on clinic-based immunization rates and on the conclusions of a randomized controlled trial.

METHODS

The study was a post hoc analysis of a cluster-randomized controlled trial. Infant randomization to the immunization intervention (4 clinics) or control group (4 clinics) was based on the site of their 2-week well-child care visit. The study was conducted at an integrated inner-city health care system serving a low-income population. A total of 2190 infants born between July 1, 1998, and June 30, 1999, who attended at least 1 postnatal visit, participated. In control sites, clinic staff documented inactive infants in the immunization registry and medical charts. The research staff undertook additional patient tracking efforts in the intervention clinics.

RESULTS

Control clinics identified 155 (13.4%) of 1160 children as inactive within 1 year of birth, whereas 284 (27.6%) of 1030 intervention infants were documented as inactive (P < .001). In bivariate analyses from the randomized trial, immunization rates differed between intervention and control branches. In multivariate models, immunization rates were significantly higher in the intervention branch when inactive infants were removed (adjusted relative risk 1.58; 95% confidence interval, 1.28-1.89), but not when they were included (adjusted relative risk 1.09; 95% confidence interval, 0.97-1.21).

CONCLUSIONS

Additional patient tracking efforts can dramatically influence inactive patient documentation and clinic-based immunization rates used for various purposes.

Vaccine shortages: history, impact, and prospects for the future

Vaccine shortages can result from higher-than-expected demand, interruptions in production/supply, or a lack of resources to purchase vaccines. Each of these factors has played a role in vaccine shortages in the United States during the past 20 years. Since 2000, the United States has experienced an unprecedented series of shortages of vaccines recommended for widespread use against 9 diseases, after more than 15 years without vaccine supply problems. In developing countries, the major cause of vaccine shortages is lack of resources to purchase them. Although there are several steps that could reduce the likelihood of future vaccine shortages, many would take several years to implement. Consequently, we will probably continue to see occasional shortages of vaccines in the United States in the next few years.

Individually Significant Risk Factors Do Not Provide an Accurate Clinical Prediction Rule for Infant Underimmunization in One Disadvantaged Urban Area

OBJECTIVE

To define a clinical prediction rule for underimmunization in children of low socioeconomic status.

METHODS

We assessed a cohort of 1160 infants born from July 1998 through June 1999 at an urban safety net hospital that received primary care at 4 community health centers. The main outcome measure was up-to-date status with the 3:2:2:2 infant vaccine series at 12 months of age.

RESULTS

Latino infants (n = 959, 83% of cohort) had immunization rates of 74%, at least 18% higher than any other racial/ethnic group. Multivariate logistic regression demonstrated the following independent associations (relative risk, 95% confidence interval) for inadequate immunization: non-Latino ethnicity (1.7, 1.4-2.0), maternal smoking (1.3, 1.1-1.7), no health insurance (1.9, 1.4-2.3), late prenatal care (1.9, 1.5-2.3), no pediatric chronic condition (2.1, 1.2-3.1), and no intent to breast-feed (1.3, 1.1-1.6). However, the index of concordance (c-index) for this model was only 0.69. Neither excluding infants who left the health care system nor accounting for infants who were "late starters" for their first vaccines improved the predictive accuracy of the model.

CONCLUSIONS

In this predominantly Latino population of low socioeconomic status, Latino infants have higher immunization rates than other infants. However, we were unable to develop a model to reliably predict which infants in this population were underimmunized. Models to predict underimmunization should be tested in other settings. In this population, interventions to improve immunization rates must be targeted at all children without respect to individual risk factors.

Use of public school immunization data to determine community-level immunization coverage

OBJECTIVES

To evaluate whether immunization data collected on a child's entry into kindergarten, i.e., Chicago Public School Immunization Data (PSID), was comparable to coverage levels determined by the National Immunization Survey (NIS) and to use these data to identify community areas with consistently low immunization coverage.

METHODS

The Chicago Department of Public Health obtained four years of PSID (2000-2003); these data included demographic information, home address, and immunization records. Coverage levels were determined in two ways: (1) one dose of measles-containing vaccine (MCV) and (2) four doses of diphtheria and tetanus toxoids and pertussis vaccine, three doses of poliovirus vaccine, and one dose of measles-containing vaccine (the 4:3:1 series), stratified by racial/ethnic group; these levels were compared to NIS estimates for the respective time periods. We used geographic information system software to illustrate variations in coverage levels between distinct community areas within Chicago.

RESULTS

Year 2000 MCV coverage levels determined from PSID closely approximated NIS estimates (84.6% vs. 87.2% +/- 4.6%, respectively). MCV coverage levels determined by race/ethnicity from PSID were within the 95% confidence intervals (CI) for all racial categories (white, 89.5% vs. 92.2% +/- 6.4%; black, 79.0% vs. 83.5% +/- 9.4%; Hispanic, 89.5% vs. 87.5% +/- 5.8%). Comparison of PSID and NIS 4:3:1 coverage levels revealed similar findings. For each study year, PSID identified 12 community areas with consistently low MCV coverage levels, i.e., < 80%.

CONCLUSIONS

PSID closely approximated NIS coverage estimates for MCV and 4:3:1 immunization. These methods can be used by state and city health departments to identify and direct resources to communities at greatest need.

The Taiwan National Health Insurance program and full infant immunization coverage

OBJECTIVES

We compared hospital-born infants and well-baby care use associated with complete immunizations in Taiwan before and after institution of National Health Insurance (NHI).

METHODS

We used logistic regression to analyze data from 1989 and 1996 National Maternal and Infant Health Surveys of 1398 and 3185 1-year-old infants, respectively.

RESULTS

Infants born in hospitals were found to receive fewer immunizations than those born elsewhere before NHI but significantly more after NHI. Use of well-baby care correlates strongly and positively with the probability that a child will receive a full course of immunization after NHI.

CONCLUSIONS

The NHI policy of including hospitals as immunization providers facilitates access to immunization services for children born in those facilities. Through NHI provision of free well-baby care, health planners have stimulated the demand for immunization.

Measles incidence estimations based on the notification by general practitioners were suboptimal

OBJECTIVE

The aim of this study was to determine the notification by general practitioners (GPs) to the Municipal Health Service (MHS) and the presentation of measles complaints by patients to the GP during a measles epidemic in a 78% vaccinated population.

STUDY DESIGN AND SETTING

Measles cases in children under 13 years were identified via questionnaires, GPs' records, and MHS's records. Consultation rate, notification rate, and completeness of notification were determined. Determinants of consultation were identified by multivariable logistic regression analysis.

RESULTS

Among 1654 responders, 164 measles cases were identified. Consultation rate: 30%; notification rate: 30% (range among GPs: 0-62%); completeness of notification: 9%. Determinants of GP consultation: perceived seriousness of illness (adjusted OR 45; 95% CI: 6-347), self-reported complications (adjusted OR 9; 95% CI: 1-70), and need to consult for respiratory tract infections (adjusted OR 8; 95% CI: 1-51).

CONCLUSION

Incidence estimations based on the notification by GPs to the MHS are suboptimal for measles in The Netherlands. Perceived seriousness of illness seemed to be the most important factor to consult.

Quality improvement in immunization delivery following an unsuccessful immunization recall

OBJECTIVES

Within a clinic serving disadvantaged children, 1) to evaluate a multifaceted quality improvement (QI) project to improve immunization (IZ) up-to-date (UTD) rates and 2) to assess the efficacy of IZ reminder/recall performed following QI.

METHODS

A year-long QI project followed by a trial of reminder/recall. QI interventions were targeted at previously identified barriers to IZ and were designed specifically to improve the efficacy of reminder/recall. QI interventions were designed to 1) increase the use of medical record releases to document IZs received elsewhere; 2) improve the accuracy of parental contact information; and 3) reduce missed opportunities by utilizing chart prompts, provider education, and provider reminders. Following QI, we conducted a randomized trial of reminder/recall.

RESULTS

UTD rates for 7-11 month olds increased from 21% before the QI project to 52% after (P <.0001); rates for 12-18 month olds increased from 16% before QI to 44% after (P <.0001); 19-25 month olds 18% before to 33% after (P <.001). After QI, an average of 61 records per month were updated with IZs received elsewhere. However, the accuracy of parental contact information worsened (29% unreachable before QI vs 44% after, P <.001) and missed opportunities did not improve (8% before vs 6% after, P = not significant [NS]). A subsequent trial of reminder/recall did not increase UTD rates, with 17% of recalled children brought UTD vs 16% of controls (P = NS).

CONCLUSIONS

Clinic-based QI increased documented UTD rates in a disadvantaged patient population. However, IZ reminder/recall did not further increase UTD rates above the rates achieved by the QI process.

Financing immunizations in the United States

Children in the United States receive immunizations through both private and public sectors. The federal government has supported childhood immunization since 1963 through the Vaccination Assistance Act (Section 317 of the Public Health Service Act). Since 1994, the Vaccines for Children (VFC) program has provided additional support for childhood vaccines. In 2002, 41% of childhood vaccines were purchased through VFC, 11% through Section 317, 5% through state and/or local governments, and 43% through the private sector. The recent introduction of more-expensive vaccines, such as pneumococcal conjugate vaccine, has highlighted weaknesses in the current system. Adult immunization is primarily performed in the private sector. Until 1981, there was no federal support for adult immunization. Since 1981, Medicare has reimbursed the cost of pneumococcal vaccine for its beneficiaries; influenza vaccine was added in 1993. This paper summarizes the history of financing immunizations in the United States and discusses some current problems and proposed solutions.

Immunization coverage levels among 19- to 35-month-old children in 4 diverse, medically underserved areas of the United States

BACKGROUND

The National Immunization Survey demonstrates that national immunization coverage in 2002 remained near the all-time highs achieved in 2000. However, that survey cannot detect whether coverage is uniformly high within relatively small areas or populations. The measles resurgence in the early 1990s revealed that coverage was low in some areas, particularly among inner-city children from racial and ethnic minority groups. Today, identifying areas with low childhood-vaccination coverage remains important, particularly if these areas are at risk for the introduction of disease. In 1995, the Centers for Disease Control and Prevention launched a congressionally mandated demonstrated project now called the Childhood Immunization Demonstration project of Community Health Networks. This mandate specified an assessment to determine whether a network of primary care providers affiliated with university teaching hospitals could assume a public health responsibility for raising immunization levels among preschoolers in medically underserved communities. Communities with federally designated health professional shortage areas were invited to submit proposals, and 4 were selected: Detroit, MI, New York, NY, San Diego, CA, and rural Colorado.

OBJECTIVES

To measure immunization coverage among preschool children in the 4 selected medically underserved areas and determine predictors of coverage levels.

DESIGN AND SETTING

Surveys in the 4 areas were based on stratified cluster probability sample designs in which clusters of dwelling units were selected and all households in selected clusters were screened for the presence of children aged 12 to 35 months. Immunization histories were obtained from parents and providers for these children. For each age-eligible child, the information collected on utilization of immunization health services included a listing of all clinics or offices ever used for the child's well-child care and/or for obtaining immunizations. Information was also collected on whether the child currently had health insurance (public and/or private) and whether the child had a medical home. A child was classified as having a medical home if the survey respondent reported a source of well care that was the same as the source of sick care and that this place was not an emergency department.

PARTICIPANTS

Children 12 to 35 months of age in Detroit, New York, San Diego, and rural Colorado.

OUTCOME MEASURE

Community-wide up-to-date (UTD) immunization coverage levels at 19 to 35 months of age, defined as receipt of 4 doses of diphtheria and tetanus toxoids and pertussis vaccine, 3 doses of poliovirus vaccine, 1 dose of measles, mumps, and rubella vaccine, 3 doses of Haemophilus influenzae type B vaccine, and 3 doses of hepatitis B vaccine (the 4:3:1:3:3 series).

ANALYSIS

We examined the association between coverage level and independent variables and performed chi2 and t tests to determine whether differences observed within and between groups and sites were significant.

RESULTS

The overall response rate for eligible children ranged from 79.4% to 88.1%. Coverage levels for most individual vaccines were >90% in all sites except Detroit. Coverage for the 4:3:1:3:3 series was significantly higher for children in New York (84%) and San Diego (86%) than for children in Detroit (66%) and rural Colorado (75%). Demographic risk factors related to UTD immunization status varied by site. Although differences in coverage levels by ethnicity varied by site, differences were not significant. In Colorado and New York, coverage was slightly lower among Hispanic than white children (71% vs 76% and 83% vs 91%, respectively). In San Diego, coverage was lower among whites, compared with Hispanics (76% vs 85%). Coverage was also lower for African American than white children only in New York (75% vs 91%). However, in San Diego and Colorado, children receiving their vaccinations from private providers had lower coverage levels than children receiving their vaccinations from other providers (78% vs 91% and 71% vs 57%, respectively). Ictively). In all 4 sites, children for whom respondents reported having an immunization card at the time of the interview were more likely to have higher series coverage levels than children for whom a parent-held card was not available. Also, children who were UTD at 3 months of age had significantly higher vaccination-series coverage levels than children who were not UTD at 3 months of age. In addition, the vaccination coverage was lower for children in Detroit whose parents reported problems accessing the health care system because lack of transportation (46%), compared with those who did not report such problems (65%); however, this difference did not reach significance (chi2 = 6.0). In Colorado, the small proportion of children in families without a phone had a lower vaccination coverage level (58%) than those in households with a phone (75%) (chi2 = 6.3). In all sites, children who were UTD at 3 months of age and had a parent-held vaccination card were more likely to be UTD at 19 to 35 months of age.

CONCLUSIONS

Preschoolers in these medically underserved areas were not at uniform risk for underimmunization. Because they were designated as health professional shortage areas, the 4 sites in this study were expected to have low immunization-coverage rates. However, this was not the case. In fact, coverage in 3 of the 4 areas was quite high compared with US national figures (73%); only Detroit had a much lower UTD rate (66%). Efforts are needed to improve methods to identify areas with low immunization coverage so that resources can be directed to places where interventions are needed. Our results reveal that an area's need for childhood immunization interventions is not well predicted by a low number of providers per capita. Other criteria must be developed to predict areas or populations with low immunization coverage. Understanding more about the characteristics of children/provider pairs for children who are UTD at 3 months and more about the role of parental hand-held cards, along with finding strategies to improve immunization delivery by providers in Vaccines for Children Program facilities, suggest potentially productive avenues for increasing and sustaining high coverage levels.

Underimmunization in Chicago children who dropped out of WIC

BACKGROUND

The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) serves a large proportion of Chicago infants, but some discontinue participation before age 1 year. To determine if children who remained active at WIC immunization-linked sites after their first birthday were more likely to be immunized by ages 19 and 25 months than those who dropped out, a retrospective cohort study was conducted.

METHODS

Four Chicago WIC sites that used monthly voucher pick-up were chosen. Children born from July 1, 1997 to September 30, 1997 who attended these sites were eligible (N=1142). The cohort was divided into two groups: (1) active group (46%), who had a WIC visit on or after their first birthday; and (2) inactive group (54%), who had their last WIC visit before their first birthday. Children were enrolled through home visits.

RESULTS

The records for 200 children were analyzed. By age 19 months, 65 (84%) of 77 active children had received one dose of measles-mumps-rubella vaccine (MMR), compared to 82 (67%) of 123 inactive children (risk ratio [RR]=1.3; 95% confidence interval [CI], 1.1- 1.5). By age 25 months, 64 (83%) active children had received four doses of diphtheria-tetanus-pertussis vaccine (DTP), one MMR, and three doses of Haemophilus influenzae type b vaccine (Hib), compared with 64 (52%) inactive children (RR=1.6; 95% CI, 1.3-2.0).

CONCLUSIONS

In this cohort, children active in WIC after their first birthday were more likely to be immunized by ages 19 and 25 months, compared with those who were no longer active. Chicago children who drop out of WIC may represent those at highest risk for underimmunization and may require special strategies to improve coverage.

Identification and recall of children with chronic medical conditions for influenza vaccination

OBJECTIVES

Despite long-standing recommendations to provide annual influenza vaccination to children with chronic medical conditions, immunization rates are <10% in most primary care settings. Many obstacles impede implementation of these recommendations, including the challenge of identifying targeted children and the need to immunize yearly in a short time interval. The objective of this study was to assess the accuracy of billing data for identifying children who have high-risk conditions (HRCs) and need influenza vaccination and 2) to evaluate the efficacy of reminder/recall for children with HRCs.

METHODS

The study was conducted in 4 private pediatric practices in metropolitan Denver, Colorado, that share a computerized billing system and also participate in an immunization registry. For all children aged 6 to 72 months, registry records were linked with the billing database. Patients with >or=1 encounters for an HRC in the previous 24 months were selected, with HRCs identified from International Classification of Diseases, Ninth Revision, Clinical Modification diagnostic codes. Using medical records as the "gold standard," we reviewed 327 randomly selected records to determine the sensitivity, specificity, and accuracy of billing data for identifying HRCs. For children with an HRC, we then conducted a randomized, controlled trial of reminder/recall for influenza vaccination. The primary outcome of the recall trial was receipt of influenza vaccine.

RESULTS

Billing data had a sensitivity of 72% (95% confidence interval [CI]: 48%-95%), specificity of 95% (95% CI: 90%-100%), and overall accuracy of 90% (95% CI: 84%-96%) in determining which children had an HRC. Of the 17,273 patients aged 6 to 72 months, 2007 had >or=1 HRCs (12% overall; range: 9%-14% per practice). Asthma/reactive airways disease accounted for 87% of all HRCs. Reminder/recall significantly increased influenza immunization in children with HRCs, with a vaccination rate of 42% in those recalled, compared with 25% in control subjects. Recalled subjects were more likely to have an office visit (68% vs 60%) and less likely to have a missed opportunity to immunize (28% vs 37%) compared with control subjects.

CONCLUSIONS

Diagnosis-based billing data accurately identified children who had HRCs and needed annual influenza vaccination, and registry-driven reminder/recall significantly increased influenza immunization in targeted children.

Varicella in Americans from NHANES III: implications for control through routine immunization

At the time of varicella vaccine introduction in the United States, an estimated 4 million episodes of varicella occurred annually. This survey of varicella seroprevalence is the first to describe immunity to a vaccine-preventable disease prior to vaccine introduction in the United States population. The objective of this analysis is to describe patterns of naturally-acquired varicella and understand characteristics associated with infection in the varicella vaccine-naive United States population. A nationally representative cross-sectional health examination survey that included venipuncture was conducted among 21,288 U.S. participants aged 6 years and older from 1988 through 1994. Serologic evidence of varicella-zoster virus infection was measured by enzyme immunoassay of varicella-zoster virus-specific IgG antibody. The seroprevalence of IgG antibody to varicella-zoster virus increased from 86.0% in children aged 6 through 11 years to 99.6% in adults aged 40 through 49 years. Immunity to varicella remained at 99% or higher in Americans aged 50 years and older. Among persons aged 6 through 19 years, non-Hispanic black children were 40% less likely to be seropositive compared with white children (odds ratio [OR], 0.6; 95% confidence interval [CI], 0.4-0.8). Among young adults aged 20 through 39 years, women with a history of live birth (OR, 4.3; 95% CI, 2.1-8.7) and married men (OR, 2.7; 95% CI, 1.2-5.7) were more likely to have naturally-acquired immunity to varicella. This study found that, prior to use of varicella vaccine in the United States, age, race, and marital characteristics were independently associated with naturally acquired varicella. Future varicella serosurveys in Americans will provide essential information to interpret the population impact of varicella vaccine.

African-American children are at risk of a measles outbreak in an inner-city community of Chicago, 2000

BACKGROUND

Since the measles resurgence of 1989-1991, which affected predominantly inner-city preschoolers, national vaccination rates have risen to record-high levels, but rates among inner-city, preschool-aged, African-American children lag behind national rates. The threat of measles importations from abroad exists and may be particularly important in large U.S. cities. To stop epidemic transmission, measles vaccination coverage should be at least 80%.

OBJECTIVE

To determine measles vaccination rates and predictors for having received a dose of measles-containing vaccine by age 19 to 35 months among children in an inner-city community of Chicago.

METHODS

We used a cross-sectional survey with probability proportional to size cluster sampling. Immunization histories from parent-held records and providers were combined to establish a complete vaccination history.

RESULTS

A total of 2545 households were contacted, and 170 included a resident child aged 12 to 35 months. Of these, 97% (N=165 children) agreed to participate. Immunization history from a parent or provider was not available for 20 children. Among children aged 19 to 35 months with available immunization histories, 74% received measles vaccine (n=100); of these, 84% received the vaccine as recommended at ages 12 to 15 months. However, when including children without immunization histories, measles coverage levels among children aged 19 to 35 months were 64% (n=114). Among children with records, predictors for receipt of measles vaccine by age 19 to 35 months were possessing a hand-held immunization card (odds ratio [OR]=16.8; 95% confidence interval [CI]=4.2-67.1); utilizing a public health department provider for a usual source of care (OR=8.9; 95% CI=1.6-47.2); and being up-to-date for vaccines at 3 months of age (OR=5.0; 95% CI=1.8-14.1).

CONCLUSIONS

Optimistically assuming that children without immunization histories are as well immunized as children with immunization histories, the measles vaccination rate among Englewood's children aged 19 to 35 months is too low to maintain immunity (74%). Measles coverage levels lagged behind coverage reported in a national survey in Chicago (86%) and the nation as a whole (92%). Efforts to raise and sustain coverage should be undertaken.

Fragmentation of immunization history among providers and parents of children in selected underserved areas

OBJECTIVE

We assessed fragmentation of children's immunization history among providers and parents of children aged 12 to 35 months in four selected underserved areas.

STUDY DESIGN

Area probability cluster sample surveys were conducted in 1997-1998 in northern Manhattan, San Diego, Detroit, and rural Colorado. Surveys consisted of face-to-face interviews with parents followed by record checks with all named immunization providers. We used Advisory Committee on Immunization Practices recommendations to determine up-to-date (UTD) status with vaccinations. The UTD status for each child was determined in four ways: (1) according to the parent-held immunization records, (2) according to the records of the child's most recent provider, (3) according to the records of the child's second most recent provider, and (4) according to provider and parent-reconciled information.

RESULTS

In all four areas, the majority of records of the most recent provider agreed with the reconciled information. However, in all areas, the percentage of children UTD according to provider- and parent-reconciled information was higher than the percentage of children UTD according to information from only the child's most recent provider or from only parent-held immunization records. Across all sites, the percentage of children UTD with the DTP/DTaP vaccine was 2% to 9% lower, according to the most recent provider's information than according to reconciled information. Similar results were seen for other vaccines. The most recent provider not having complete immunization history was significantly associated with not being UTD in New York and having received unnecessary immunizations in San Diego and Detroit.

CONCLUSION

For most children, although the records of the most recent provider give accurate data for clinical decision making, the immunization histories of some children in these underserved areas are fragmented between providers and parents. This can limit the provider's ability to vaccinate children appropriately.

Health department clinics as pediatric immunization providers: a national survey

OBJECTIVE

To describe a national sample of health department immunization clinics in terms of populations served, patient volume trends, services offered, and immunization practices.

METHODS

Telephone survey conducted with health departments sampled from a national database, using probability proportional to population size.

RESULTS

All (100%) 166 sampled and eligible clinics completed the survey. The majority of pediatric patients were uninsured (42%) or enrolled in Medicaid (34%). Most children (69%) and adolescents (70%) were referred to the health department, with only 12% using these clinics as a medical home. A number of clinics (72%) reported recent increases in adolescents served. Less than 25% of clinics offered comprehensive care, 47% conducted semiannual coverage assessments, and 76% and 38% operated recall systems for children and adolescents. Storage of records in an electronic database was common (83%).

CONCLUSIONS

Although the majority of these clinics do not provide comprehensive care, they continue to serve vulnerable children, including adolescents, Medicaid enrollees, and the uninsured, and may represent the main contact with the healthcare system for such patients. Because assuring the immunization of these children is essential to their health and the health of our nation as a whole, this immunization safety net must be preserved. Experience implementing key recommendations such as coverage assessment and feedback as well as reminder or recall may enable health department staff to assist private provider colleagues. Further research is needed to investigate how patient populations, services offered, and immunization practices vary by different clinic characteristics.