Influenza vaccine coverage and missed opportunities among inner-city children aged 6 to 23 months: 2000-2005

Influenza Vaccine Hesitancy: Scope, Influencing Factors, and Strategic Interventions

Influenza vaccination rates in children are suboptimal. One underlying reason is influenza vaccine hesitancy. Tools such as the Parent Attitudes about Childhood Vaccines survey and the Vaccine Hesitancy Scale can be used to measure influenza vaccine hesitancy. The adapted Increasing Vaccination Model from Brewer and colleagues can help identify factors that influence influenza vaccine hesitancy, motivation, and uptake. Several strategies can be used to address influenza vaccine hesitancy, which we discuss further in this review.

Can vaccination coverage be improved through reducing the missed opportunities for immunization? Results from the evaluation in Zhejiang province, east China

BACKGROUND

To evaluate the missed opportunities for vaccination (MOV) in Zhejiang province by using the global methodology from World Health Organization (WHO).

METHODS

Based on the WHO Planning Guide to Reduce Missed Opportunities for Vaccination (MOV) and Methodology for the Assessment of MOV, 33 health facilities from 11 cities in Zhejiang province were selected. For each health facility, exit investigations for 20 caregivers of children aged 0-23 months and knowledge, attitudes, and practices (KAP) surveys for 10 health workers was implemented. A MOV was determined based on the child's age on the date of investigation, eligibility for various vaccines. The prevalence of MOV was calculated and the risk factors of MOV were explored.

RESULTS

There were 660 completed exit investigations of caregivers of children aged 0-23 months and 330 health worker KAP investigations. Of the 658 children with documented vaccination records, 12.6% were still under-vaccinated. Among these under-vaccinated children, 54.2% still had a MOV. Children's age and their previous vaccination behavior, as well as caregivers' relationship to children and education level had a significant impact on the incidence of MOV.

CONCLUSION

The high proportions of visits with MOV in Zhejiang province suggested that interventions to reduce MOV in health service settings may be a potential quick win for improving coverage and equity. National immunization programs should explore the tailored efforts to improve health worker practices by making better use of existing health service contacts.

Countering vaccine hesitancy through immunization information systems, a narrative review

Immunization is one of the most important public health interventions to contrast infectious disease; however, many people nowadays refuse vaccination. Vaccine hesitancy (VH) is due to several factors that influence the complex decision-making process. Information technology tools might play an important role in vaccination programs. In particular, immunization information systems (IISs) have the potential to improve performance of vaccination programs and to increase vaccine uptake. This review aimed to present IIS functionalities in order to counter VH. In detail, we analyzed the automatic reminder/recall system, the interoperability of the system, the decision support system, the web page interface and the possibility to record adverse events following immunization. IIS could concretely represent a valid instrument to increase vaccine confidence, especially trust in both health-care workers and decision makers. There are not enough trials aimed to evaluate the efficacy of IIS to counter VH. Further researches might focalize on this aspect.

Parental Vaccine Hesitancy and Declination of Influenza Vaccination Among Hospitalized Children

OBJECTIVES

Parents frequently decline the influenza vaccine for their child during hospitalization. In this study, we aimed to assess the role of vaccine hesitancy in these declinations.

METHODS

This cross-sectional survey study was conducted among English-speaking parents of influenza vaccine-eligible children who were hospitalized between October 2014 and April 2015. Between July 2015 and September 2015, parents were recruited via mail to complete the validated Parent Attitudes about Childhood Vaccines (PACV) survey (modified for influenza vaccination). PACV scores (0-100 scale) were dichotomized into scores of ≥50 (hesitant) and <50 (nonhesitant). The primary outcome was parental declination of the influenza vaccine for their child during hospitalization. A secondary outcome was the declination reason documented during hospitalization. The main independent variable was parental vaccine hesitancy status, determined by the PACV score. Multivariable logistic regression was used to examine the association between vaccine hesitancy and influenza vaccine declination, adjusting for sociodemographic, visit, and clinical characteristics. The relationship between vaccine hesitancy and declination reason was also explored.

RESULTS

Of 199 parents (18% response rate), 24% were vaccine hesitant and 53% declined the influenza vaccine for their child during hospitalization. Vaccine hesitancy (versus nonhesitancy) was associated with declining influenza vaccination (adjusted odds ratio: 6.4; 95% confidence interval: 2.5-16.5). The declination reason differed by vaccine hesitancy status, with a higher proportion of parents who were hesitant versus nonhesitant reporting "vaccine concern" or "vaccine unnecessary."

CONCLUSIONS

Vaccine hesitancy was prevalent in this limited sample of parents of hospitalized children and associated with influenza vaccine declination. Additional investigation in a large, diverse, prospectively recruited cohort is warranted given the potential sampling bias present in this study.

A systematic review of strategies for reducing missed opportunities for vaccination

BACKGROUND

Missed opportunities for vaccination (MOVs) occur when persons eligible for vaccination visit a health facility and do not get the vaccines they need. We conducted a systematic review to assess effects of interventions for reducing MOVs.

METHODS

We searched PubMed, Scopus, and the Cochrane Central Register of Controlled Trials in April 2017. Three authors independently screened search outputs, reviewed potentially eligible papers, assessed risk of bias, and extracted data; resolving disagreements by consensus. We expressed study results as risk ratios (RR) with 95% confidence intervals (CI) and assessed the certainty of the evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool.

RESULTS

Six studies (five trials and one cohort study) met our inclusion criteria, all conducted in the United States of America. All six studies had various limitations and were classified as having a high risk of bias. We found moderate certainty evidence that the following interventions probably improve vaccination coverage: patient education (RR 1.92, 95% CI 1.38-2.68), patient tracking using community health workers (RR 1.18, 95% CI 1.11-1.25), and patient tracking and provider prompts (RR 1.24, 95% CI 1.18-1.31). In addition, we found low certainty evidence that concurrent interventions targeting health-facility (education, prompts, and audit and feedback) and family settings (phone calls) may increase vaccination coverage (RR 1.25, 95% CI 1.08-1.46).

CONCLUSIONS

The currently available evidence suggests that patient education, patient tracking, outreach sessions, and provider prompts reduce missed opportunities for vaccination and improve vaccination coverage. Rigorous studies are required to confirm these findings and increase the certainty of the current evidence base. WHO is currently coordinating efforts to generate such evidence, especially from low-income and middle-income countries, and it is likely that the data will be available in the next few years.

Cost-effectiveness of seasonal quadrivalent versus trivalent influenza vaccination in the United States: A dynamic transmission modeling approach

Trivalent inactivated influenza vaccines (IIV3s) protect against 2 A strains and one B lineage; quadrivalent versions (IIV4s) protect against an additional B lineage. The objective was to assess projected health and economic outcomes associated with IIV4 versus IIV3 for preventing seasonal influenza in the US. A cost-effectiveness model was developed to interact with a dynamic transmission model. The transmission model tracked vaccination, influenza cases, infection-spreading interactions, and recovery over 10 y (2012–2022). The cost-effectiveness model estimated influenza-related complications, direct and indirect costs (2013–2014 US$), health outcomes, and cost-effectiveness. Inputs were taken from published/public sources or estimated using regression or calibration. Outcomes were discounted at 3% per year. Scenario analyses tested the reliability of the results. Seasonal vaccination with IIV4 versus IIV3 is predicted to reduce annual influenza cases by 1,973,849 (discounted; 2,325,644 undiscounted), resulting in 12–13% fewer cases and influenza-related complications and deaths. These reductions are predicted to translate into 18,485 more quality-adjusted life years (QALYs) accrued annually for IIV4 versus IIV3. Increased vaccine-related costs ($599 million; 5.7%) are predicted to be more than offset by reduced influenza treatment costs ($699 million; 12.2%), resulting in direct medical cost saving annually ($100 million; 0.6%). Including indirect costs, savings with IIV4 are predicted to be $7.1 billion (5.6%). Scenario analyses predict IIV4 to be cost-saving in all scenarios tested apart from low infectivity, where IIV4 is predicted to be cost-effective. In summary, seasonal influenza vaccination in the US with IIV4 versus IIV3 is predicted to improve health outcomes and reduce costs.

Transcranial Doppler Screening Among Children and Adolescents With Sickle Cell Anemia

IMPORTANCE

With transcranial Doppler (TCD) screening, we can identify children and adolescents with sickle cell anemia who are at the highest risk of stroke. An accurate claims-based method for identifying children and adolescents with sickle cell anemia was recently developed and validated that establishes the necessary groundwork to enable large population-based assessments of health services utilization among children and adolescents with sickle cell anemia using administrative claims data.

OBJECTIVE

To assess the feasibility of using administrative claims data to identify and describe the receipt of TCD screening among children and adolescents with sickle cell anemia and to characterize opportunities for intervention.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cross-sectional study using Medicaid claims data from 2005 to 2010. Medicaid claims data were obtained from the following states: Florida, Illinois, Louisiana, Michigan, South Carolina, and Texas. Children and adolescents 2 to 16 years of age with sickle cell anemia were identified by the presence of 3 or more Medicaid claims with a diagnosis of sickle cell anemia within a calendar year (2005-2010). A total of 4775 children and adolescents contributed 10 787 person-years throughout the study period. Data were analyzed in 2015. A subset of children and adolescents enrolled for 2 or more consecutive years was identified to examine potential predictors of TCD screening, which included age, sex, previous receipt of TCD screening, state of residence, and health services utilization (well-child visits, outpatient visits, emergency department visits, and inpatient visits).

MAIN OUTCOMES AND MEASURES

Receipt of TCD screening was assessed by year and state. Using logistic regression with generalized estimating equations, we included associated predictors in a multivariable model to estimate odds of TCD screening.

RESULTS

For a total of 4775 children and adolescents 2 to 16 years of age, TCD screening rates increased over the 6-year study period from 22% to 44% (P < .001); rates varied substantially across states. A subset of 2388 children and adolescents with sickle cell anemia (50%) was enrolled for 2 or more consecutive years. Each year of increasing age was associated with 3% lower odds of TCD screening (odds ratio, 0.97 [95% CI, 0.95-0.98]; P = .002). Previous receipt of TCD screening (odds ratio, 2.44 [95% CI, 2.11-2.81]; P < .001) and well-child visits (odds ratio, 1.10 [95% CI, 1.03-1.18]; P = .007) were associated with higher odds of receiving a TCD screening.

CONCLUSIONS AND RELEVANCE

Despite national recommendations, TCD screening rates remain low. Successful strategies to improve TCD screening rates may capitalize on the numerous health care interactions among children and adolescents with sickle cell anemia.

Registry-linked electronic influenza vaccine provider reminders: a cluster-crossover trial

OBJECTIVE

To determine the impact of a vaccination reminder in an electronic health record supplemented with data from an immunization information system (IIS).

METHODS

A noninterruptive influenza vaccination reminder, based on a real-time query of hospital and city IIS, was used at 4 urban, academically affiliated clinics serving a low-income population. Using a randomized cluster-crossover design, each study site had "on" and "off" period during the fall and winter of 2011-2012. Influenza vaccination during a clinic visit was assessed for 6-month to 17-year-old patients. To assess sustainability, the reminder was active at all sites during the 2012-2013 season.

RESULTS

In the 2011-2012 season, 8481 unique non-up-to-date children had visits. Slightly more non-up-to-date children seen when the reminder was 'on' were vaccinated than when 'off' (76.2% vs 73.8%; P = .027). Effects were seen in the winter (67.9% vs 62.2%; P = .005), not fall (76.8% vs 76.5%). The reminder also increased documentation of the reason for vaccine non-administration (68.1% vs 41.5%; P < .0001). During the 2011-2012 season, the reminder displayed for 8630 unique visits, and clinicians interacted with it in 83.1% of cases where patients required vaccination. During the 2012-2013 season, it displayed for 22 248 unique visits; clinicians interacted with it in 84.8% of cases.

CONCLUSIONS

An IIS-linked influenza vaccination reminder increased vaccination later in the winter when fewer vaccine doses are usually given. Although the reminder did not require clinicians to interact with it, they frequently did; utilization did not wane over time.

Effectiveness of primary care-public health collaborations in the delivery of influenza vaccine: a cluster-randomized pragmatic trial

OBJECTIVE

To assess effectiveness and feasibility of public-private collaboration in delivering influenza immunization to children.

METHODS

Four pediatric and four family medicine (FM) practices in Colorado with a common public health department (PHD) were randomized at the beginning of baseline year (10/2009) to Intervention (joint community clinics and PHD nurses aiding in delivery at practices); or control involving usual care without PHD. Generalized estimating equations compared changes in rates over baseline between intervention and control practices at end of 2nd intervention year (Y2=5/2011). Barriers to collaboration were examined using qualitative methods.

RESULTS

Overall, rates increased from baseline to Y2 by 9.2% in intervention and 3.2% in control (p<.0001), with significant increases in both pediatric and FM practices. The largest increases were seen among school-aged and adolescent children (p<.0001 for both), with differences for 6-month-old to 5-year-old children and for children with high-risk conditions not reaching significance. Barriers to collaboration included uncertainty regarding the delivery of vaccine supplies, concerns about using up all purchased vaccine by practices, and concerns about documentation of vaccination if collaboration occurred.

CONCLUSIONS

In spite of barriers, public-private collaboration resulted in significantly higher influenza immunization rates, particularly for older, healthy children who visit providers less frequently.

Seasonal influenza vaccination trends from 2007-2011 in privately insured children and adults in the United States

BACKGROUND

To ensure adequate protection from seasonal influenza in the US, the Advisory Committee on Immunization Practices recommends vaccination of all persons aged 6 months or older, with rare exceptions. It also advises starting vaccination as soon as available and continuing throughout the influenza season. This study examined US seasonal vaccination trends during five consecutive influenza seasons in privately-insured children and adults.

METHODS

This retrospective, observational cohort study examined trends in influenza vaccination during the 2007-2008 through 2011-2012 influenza seasons using administrative claims data from a large national insurer.

RESULTS

The size of analysis population ranged from 1144,098 to 1245,487 (children, ≥6 months-17 years of age) and from 3931,622 to 4158,223 (adults, 18-64 years of age). Vaccination frequency increased through 2010-2011, was most frequent in young children, and decreased with age. Vaccination rates were highest in the Northeast and lowest in the West and were higher in individuals with frequent outpatient office visits than in those with no or rare visits, with larger differences seen in children. Between 2007 and 2011, the use of preservative-free inactivated vaccine increased, the use of multidose vaccines containing preservatives decreased, and the use of live attenuated influenza vaccines increased among children 2-17 years of age. From 2007-2008 through 2009-2010, the timing of vaccination each year began earlier than the previous one; it remained stable from 2009-2010 through 2011-2012.

CONCLUSION

Annual influenza vaccination claims for privately-insured children and adults increased and shifted earlier from 2007 through 2009-2011. During the 2011-2012 influenza season, 25.4% of children aged 6 months-17 years and 12.3% of adults aged 18-64 years were vaccinated. Increasing influenza vaccination should remain a priority, and alternative venues for seasonal influenza vaccination should be considered in order to meet the Healthy People 2020 goal of 80% to 90% coverage among children.

Cervical cytology screening among low-income, minority adolescents in New York City following the 2009 ACOG guidelines

OBJECTIVES

In December 2009, the American College of Obstetricians and Gynecologists recommended that cervical cancer screening begin at age 21 for young women. In this study, we examine receipt of first lifetime Papanicolaou (Pap) test and predictors of over-screening among adolescents within a large urban ambulatory care network.

METHODS

We compared the proportion of first lifetime Pap test of adolescents aged 13-20years between June 2007 - November 2009 (n=7700) and December 2009-June 2012 (n=9637) using electronic health records. We employed multivariable regression models to identify demographic and health care factors associated with receiving a first lifetime Pap test at age <21years in the post-guideline period (over-screening).

RESULTS

The proportion of Pap tests declined from 19.3% to 4.2% (p<0.001) between the two periods. Multivariable logistic regression results showed receiving care from gynecologic/obstetric/family planning clinics compared to pediatric clinics, having more clinic encounters, and older age were associated with over-screening in the post-guideline period.

CONCLUSIONS

We found that guideline adherence differed by clinic type, insurance status, and health care encounters. In the quickly evolving field of cervical cancer control, it is important to monitor practice trends as they relate to shifts in population-based guidelines, especially in high-risk populations.

Evaluation of the frequency of immunization information system use for public health research

Immunization information systems (IIS) have been useful for consolidating immunization data and increasing coverage, and have the potential to be a valuable resource for immunization research, but the extent which IIS data are used for research purposes has not been evaluated. We reviewed studies conducted using data from federally supported state and city immunization program IIS, and categorized research type based on study objectives to evaluate patterns in the types of research conducted. Research papers using IIS data published between 1999 and July 3, 2012 were identified by searching the CDC IIS publication database and PubMed. These searches produced 304 and 884 papers, respectively, 44 of which were eligible to be included in this evaluation. The most common research category was evaluation of factors associated with vaccine coverage and vaccine coverage estimates (n = 20). This study shows that IIS may not be used to their full potential with regards to research. Further research is needed to determine barriers to using IIS data for research purposes.

Timeliness of pediatric influenza vaccination compared with seasonal influenza activity in an urban community, 2004-2008

OBJECTIVES

We assessed pediatric influenza vaccination in relation to community influenza activity.

METHODS

We examined seasonal influenza vaccination in 34,012 children aged 6 months through 18 years from 5 academically affiliated clinics in northern Manhattan, New York (an urban low-income community) during the 2004-2008 seasons using hospital and city immunization registries. We calculated the cumulative number of administered influenza vaccine doses and proportion of children with any (≥ 1 dose) or full (1-2 doses per age recommendations) vaccination at the onset and peak of community polymerase chain reaction-confirmed influenza activity according to state surveillance reports and by March 31 each season.

RESULTS

Influenza vaccine administration began before October 1, peaked before influenza activity onset, and declined gradually over each season. Coverage at influenza activity onset, peak, and by March 31 increased over the 5 seasons. However, most children lacked full vaccination at these time points, particularly adolescents, minorities, and those requiring 2 doses.

CONCLUSIONS

Despite early initiation of influenza vaccination, few children were fully vaccinated when influenza began circulating. Interventions should address factors negatively affecting timely influenza vaccination, especially in high-risk populations.

Influenza vaccination coverage and timeliness among children requiring two doses, 2004-2009

OBJECTIVE

To assess influenza vaccination coverage and timeliness among children requiring two doses in a season.

METHODS

This study examined seasonal influenza vaccination of 17,800 children from five academically-affiliated clinics in New York City using hospital and city immunization registries. Eligible children were 6 months-8 years and needed two influenza vaccine doses in a given season between 2004-05 and 2009-10. Any (≥ 1 dose) and full (2 doses) vaccination coverage by December 15 and March 31 as well as interval between doses were calculated. Vaccination trends over time, determinants, and missed opportunities were assessed.

RESULTS

Children were primarily Latino and publicly insured. Full coverage by March 31 increased between the 2004-05 and 2009-10 seasons (9% vs. 29%, p<0.001). Few children received both doses by December 15 (2-13%). The interval between doses was almost twice as long as recommended and increased over time (2004-05: 52 days; 2009-10: 64 days; p<0.001). Older age and Latino ethnicity were negative predictors of full vaccination by March 31. Missed opportunities for the second dose were common.

CONCLUSION

Despite improvements, low-income, minority children requiring two influenza vaccine doses remain at risk of incomplete and delayed vaccination. Barriers to and strategies for timely full vaccination should be explored.

The impact of missed opportunities on seasonal influenza vaccination coverage for healthy young children

OBJECTIVE

To estimate the impact of missed opportunities on influenza vaccination coverage among 6- through 23-month-old children who sought medical care during the 2004-2005 influenza season.

DESIGN

Retrospective cohort study.

SETTING

Fifty-two primary care practice sites located in Rochester, New York, Nashville, Tennessee, and Cincinnati, Ohio.

PARTICIPANTS

Children 6 through 23 months of age. METHODS/OUTCOME MEASURE: Charts were reviewed and data collected on influenza vaccinations, type of health care visit (well child or other), and presence of illness symptoms. Missed opportunity was defined as a practice visit by an eligible child during influenza season, when vaccine was available, but during which the child did not receive an influenza vaccination. Vaccine was assumed to be available between the first and last dates influenza vaccination was recorded at that practice. Each child was classified as fully vaccinated, partially vaccinated, or unvaccinated.

RESULTS

Data were analyzed for 1724 children, 6 through 23 months of age. Most children (62.0%) had at least 1 missed opportunity during this period. Among children with any missed opportunities, 12.8% were fully and 29.8% were partially vaccinated. Overall, 33.6% of the missed opportunities occurred during well child visits and 66.4% during other types of visits; 75% occurred when no other vaccines were given. Eliminating all missed opportunities would have increased full vaccination coverage from 30.3% to 49.9%.

CONCLUSIONS

Missed opportunities for influenza vaccination are frequent. Reducing missed opportunities could significantly increase influenza vaccination rates and should be a goal in each practice.

FluAlert: a qualitative evaluation of providers' desired characteristics and concerns regarding computerized influenza vaccination alerts

OBJECTIVE

To explore pediatric providers' perceived barriers to influenza vaccine delivery, and desired characteristics and potential concerns regarding an influenza vaccine alert integrated into the electronic health record (EHR).

METHODS

Four focus groups with providers (n=21) and five individual interviews with practice leaders in an urban, pediatric primary care network affiliated with an academic medical center in New York City were conducted. Data were collected during the 2009-10 influenza season and analyzed using thematic analysis.

RESULTS

Participants identified several barriers to influenza vaccine delivery, including remembering to vaccinate during sick visits, need to review multiple sources of immunization information, time shortages and inadequate staffing. They felt that an alert could help many of these challenges. They desired the following alert characteristics: 1) alerting providers early in the visit, 2) accurately determining patients' vaccine status by merging multiple sources of immunization information, 3) facilitating vaccine ordering, and 4) generating appropriate documentation in the EHR when vaccines were refused or otherwise not given. Potential concerns regarding the alert included reliability and accuracy of alert, workflow interruptions and forced actions.

CONCLUSIONS

This study highlights providers' interest in a well-integrated, accurate alert that streamlines assessment of vaccination eligibility, ordering and documentation without impeding work-flow.

Timing of the availability and administration of influenza vaccine through the vaccines for children program

BACKGROUND

influenza vaccine must be distributed and administered each year during a limited time interval. To our knowledge, no previous studies have simultaneously evaluated the delivery and administration of privately purchased vaccines and influenza vaccines acquired through the Vaccines for Children (VFC) program.

METHODS

a prospective, observational study was conducted in US outpatient pediatric offices, tracking all influenza vaccinations during the season by age group, first or second vaccination, the child's need for 1 or 2 doses, type of vaccine, and VFC status.

RESULTS

a total of 42 and 84 practices completed the study in 2007 to 2008 and 2008 to 2009, respectively. In both seasons, initial shipments of VFC influenza vaccine generally arrived 4 to 5 weeks later than non-VFC shipments; VFC vaccine administration also started 1 month later than administration of privately purchased vaccine. Vaccine administration peaked in early November and late October in years 1 and 2, respectively, and declined rapidly thereafter. Overall, approximately one-half of all children who required 2 doses of vaccine were estimated to have received 2 doses. In both years, 2-dose compliance rates in the VFC population were 17% to 19% lower than those in the non-VFC population, possibly resulting from the VFC population's shorter time interval for second dose receipt.

CONCLUSIONS

the VFC program is critical to ensuring financially vulnerable children have access to vaccination. Manufacturers, distributors, and public health officials should deliver VFC influenza vaccine to providers as quickly as possible. Pediatric healthcare providers should increase efforts to vaccinate all populations, especially the VFC population, in later months.

A prospective observational study of US in-office pediatric influenza vaccination during the 2007 to 2009 influenza seasons: use and factors associated with increased vaccination rates

In the United States, annual influenza vaccine is now recommended for all children 6 months through 18 years of age. This 2-year observational study of US outpatient pediatricians' offices captured office demographics and characteristics, recorded all influenza vaccinations administered and vaccination-related activities during the influenza season, and correlated office characteristics and activities associated with increased vaccine uptake. Offices generally offered the influenza vaccine from September through February and March; however, approximately 80% of vaccinations occurred in October through December. In 2008-2009 compared with 2007-2008, offices administered the vaccine earlier and later into the season. Estimated in-office rates of first-dose administration, 2-dose compliance, and use of the intranasal vaccine also increased. Qualitative analyses suggest that increased first-dose administration and 2-dose compliance rates are associated with smaller office size and a greater duration of vaccine availability, respectively, during both seasons.

Practice and child characteristics associated with influenza vaccine uptake in young children

OBJECTIVES

The objective of this study was to determine both practice and child characteristics and practice strategies associated with receipt of influenza vaccine in young children during the 2004-2005 influenza season, the first season for the universal influenza vaccination recommendation for all children who are aged 6 to 23 months.

METHODS

Clinical and demographic data from randomly selected children who were aged 6 to 23 months were obtained by chart review from a community-based cohort study in 3 US counties. The proportion of children who were vaccinated by April 5, 2005, in each practice was obtained. For assessment of practice characteristics and strategies, sampled practices received a self-administered practice survey. Practice and child characteristics that predicted complete influenza vaccination were determined by using multinomial logistic regression.

RESULTS

Forty-six (88%) of 52 sampled practices completed the survey and permitted chart reviews. Of 2384 children who were aged 6 to 23 months and were studied, 27% were completely vaccinated. The proportion of children who were completely vaccinated varied widely among practices (0%-71%). Most (87%) practices implemented ≥1 vaccination strategy. Complete influenza vaccination was associated with 3 practice characteristics: suburban location, lower patient volume, and vaccination strategies of evening/weekend vaccine clinics; with child characteristics of younger age, existing high-risk conditions, ≥6 well visits to the practice by 3 years of age, and any practice visit from October through January.

CONCLUSIONS

Modifiable factors that were associated with increased influenza vaccination coverage included October to January practice visits and evening/weekend vaccine clinics.

Changes in Tdap and MCV4 vaccine coverage following enactment of a statewide requirement of Tdap vaccination for entry into sixth grade

OBJECTIVES

We evaluated changes in tetanus toxoid, reduced diphtheria toxoid, acellular pertussis (Tdap), and tetravalen meningococcal (MCV4) vaccine coverage following enactment of a New York State mandate requiring Tdap before entering sixth grade.

METHODS

Using data from a hospital-based immunization registry, we measured Tdap and MCV4 coverage among youths aged 11 to 14 years in New York City at 3 time points: premandate, mandate year 1, and mandate year 2.

RESULTS

Among overlapping cohorts of 4316 (premandate), 4131 (mandate year 1), and 3639 (mandate year 2) youths, Tdap coverage increased steadily over time (29%, 58%, and 83%, respectively). Increases were observed among all ages. Across the same time points, MCV4 coverage also increased (10%, 30%, and 60%, respectively). Most adolescents did not receive MCV4 during the same visit they received Tdap.

CONCLUSIONS

A Tdap school-entry mandate was associated with substantial increases in immunization coverage, even in age groups not directly affected by the mandate. At the postmandate time points, MCV4 coverage remained lower than Tdap coverage. Provider education should emphasize the importance of reviewing vaccine records and administering all recommended vaccines at every clinical encounter.

Health care utilization by adolescents on medicaid: implications for delivering vaccines

OBJECTIVE

To examine the degree to which current health care utilization patterns of Medicaid-enrolled adolescents living in Michigan would allow opportunities for adolescent immunizations to be provided.

METHODS

Outpatient claims data from 2001-2005 were analyzed for 11- to 18-year-old Medicaid-enrolled adolescents living in Michigan. Visits were classified as either health-maintenance examinations (HMEs) or problem focused by using diagnostic and procedural codes. Data were divided into 4 overlapping 2-year time periods, and the age-specific proportion of adolescents who attended these 2 visit types was calculated for each. chi(2) tests were used to evaluate associations of visit patterns with gender.

RESULTS

Of the 718847 adolescents included in the study, <50% had >or=1 HME visit within any 2-year time period, and substantially fewer (<15%) had annual HMEs. In contrast, at least 75% of the adolescents had >or=1 problem-focused visit in any given 2-year period, and approximately half had participated in at least 2 problem-focused visits. Problem-focused, but not HME, visit utilization was significantly associated with gender, with girls increasing, but boys decreasing, visit utilization as they aged.

CONCLUSIONS

Similar to privately insured adolescents, most Medicaid-enrolled adolescents do not have annual preventive-care visits, which calls into question the feasibility of providing immunizations primarily at annual HMEs. Participation in problem-focused encounters was generally high in our study. However, even problem-focused visit utilization was low among older adolescent boys. This suggests that in addition to strengthening immunization within the medical home, alternative venues for reaching certain subpopulations of adolescents should also be developed.