Advancing the National Immunization Program in an era of achieving universal vaccine coverage in China and beyond

BACKGROUND

Immunization is a cornerstone of public health. Despite great success, China's National Immunization Program (NIP) faces challenges, such as the integration of several World Health Organization-recommended vaccines and other systemic issues. The Innovation Laboratory for Vaccine Delivery Research (VaxLab), supported by the Bill & Melinda Gates Foundation and established in 2021 at Duke Kunshan University, focuses on enhancing China's NIP through research and policy advocacy. This editorial aims to summarize the key findings of the manuscripts published in the collection contributed by VaxLab team and set the future research agenda.

KEY FINDINGS

The collection contains eleven manuscripts discussing China's immunization landscape and strategies to improve coverage, particularly for non-NIP vaccines like human papillomavirus vaccine (HPV), pneumococcal conjugate vaccine (PCV), Haemophilus influenzae type b vaccine (Hib), and rotavirus vaccines. Key findings include: (i) The COVID-19 vaccination campaign demonstrated China's capacity for rapid, large-scale immunization efforts, suggesting potential for broader vaccine coverage improvements; (ii) Efforts in combating cervical cancer through the HPV vaccine indicate progress but also highlight challenges like vaccine supply and equitable access; (iii) The lag in adopting higher-valent paediatric combination vaccines in China needs attention to address regulatory and health system hurdles; (iv) Disparities in access to non-NIP vaccines underscore the need for government initiatives to improve vaccine coverage, especially for remote areas and marginalized populations; (v) Original studies emphasize the influence of caregivers' knowledge, health workers' financial incentives, and concerns about vaccine efficacy on immunization rates; (vi) Case studies from the Weifang City of China and Indonesia to introduce PCV offer insights on successful vaccine introduction strategies and the impact of innovative financing and government support.

CONCLUSION

The articles emphasize the need for government leadership, strategic policymaking, and public awareness to enhance vaccine coverage and equity. The VaxLab will continue strengthening China's NIP by focusing on vaccine financing, emphasizing diversity, equity, and inclusion, and improving maternal vaccination coverage. Research will extend to Southeast Asian and Western Pacific regions, especially in middle-income countries facing challenges in vaccine financing and delivery. The collective efforts outlined in this collection show a commitment to evolving and adapting immunization strategies to meet global health goals and to provide equitable access to vaccines for all.

An Observational Prospective Cohort Study of Vaccine Effectiveness Against Severe Acute Respiratory Syndrome Coronavirus 2 Infection of an Aerosolized, Inhaled Adenovirus Type 5-Vectored Coronavirus Disease 2019 Vaccine Given as a Second Booster Dose in Guangzhou City, China

Using a prospective, observational cohort study during the post-"dynamic COVID-zero" wave in China, we estimated short-term relative effectiveness against Omicron BA.5 infection of inhaled aerosolized adenovirus type 5-vectored ancestral strain coronavirus disease 2019 (COVID-19) vaccine as a second booster dose approximately 1 year after homologous boosted primary series of inactivated COVID-19 vaccine compared with no second booster. Participants reported nucleic acid or antigen test results weekly until they tested positive or completed predesignated follow-up. After excluding participants infected <14 days after study entry, relative effectiveness among the 6576 participants was 61% in 18- to 59-year-olds and 38% in ≥60-year-olds and was sustained for 12 weeks.

Accelerating into Immunization Agenda 2030 with momentum from China's successful COVID-19 vaccination campaign during dynamic COVID Zero

China's immunization programs conducted a unified, tightly coordinated COVID-19 vaccination campaign during the dynamic COVID Zero period that reached well over 90% of the population with vaccines having > 90% effectiveness against serious-to-fatal COVID-19. The campaign was eight times the size of the annual routine national immunization program, administering 3.4 billion doses of vaccines while monitoring vaccine coverage, acceptability, safety, and effectiveness. Every asset of the routine immunization program had to be strengthened and expanded to attain high coverage and reach hundreds of millions of adults who had not been vaccinated since childhood. Program strengthening and expansion were in directions aligned with the World Health Organization's Immunization Agenda 2030, which has a vision that "everyone, everywhere, at every age fully benefits from vaccines for good health and well-being" and requires reaching all children, adolescents, and adults with lifesaving vaccines. Momentum from this campaign should not be lost but should be invested into achieving what is possible with a properly resourced national immunization program that is now proven to be capable of reaching everyone in the world's largest country throughout the life course, and to do so with all vaccines recommended by the World Health Organization.

Real-World Effectiveness of Primary Series and Booster Doses of Inactivated Coronavirus Disease 2019 Vaccine Against Omicron BA.2 Variant Infection in China: A Retrospective Cohort Study

BACKGROUND

China has been using inactivated coronavirus disease 2019 (COVID-19) vaccines as primary series and booster doses to protect the population from severe to fatal COVID-19. We evaluated primary and booster vaccine effectiveness (VE) against Omicron BA.2 infection outcomes.

METHODS

This was a 13-province retrospective cohort study of quarantined close contacts of BA.2-infected individuals. Outcomes were BA.2 infection, COVID-19 pneumonia or worse, and severe/critical COVID-19. Absolute VE was estimated by comparison with an unvaccinated group.

RESULTS

There were 289 427 close contacts ≥3 years old exposed to Omicron BA.2 cases; 31 831 turned nucleic acid amplification test-positive during quarantine, 97.2% with mild or asymptomatic infection, 2.6% with COVID-19 pneumonia, and 0.15% with severe/critical COVID-19. None died. Adjusted VE (aVE) against any infection was 17% for primary series and 22% when boosted. Primary series aVE in adults >18 years was 66% against COVID-19 pneumonia or worse and 91% against severe/critical COVID-19. Booster dose aVE was 74% against pneumonia or worse, and 93% against severe/critical COVID-19.

CONCLUSIONS

Inactivated COVID-19 vaccines provided modest protection from infection, very good protection against pneumonia, and excellent protection against severe/critical COVID-19. Booster doses are necessary to provide strongest protection.

Effectiveness of DTaP Against Pertussis in ≤2-Year-Old Children - Linyi Prefecture, Shandong Province, China, 2017-2019

What is already known about this topic?

Vaccine effectiveness (VE) is positively correlated with the number of administered co-purified diphtheria, tetanus, and acellular pertussis vaccine (DTaP) doses. A matched case-control study conducted in Zhongshan City revealed that the co-purified DTaP VE against pertussis-related illnesses in children aged 4-11 months was 42% for one dose, 88% for two doses, and 95% for three doses, respectively.

What is added by this report?

The results of this study contribute to the current body of research. We found that the VE of co-purified DTaP against pertussis-related illness and hospitalization increased substantially, ranging from 24%-26% after one dose to 86%-87% after four doses.

What are the implications for public health practice?

The results of this study underscore the significance of prompt and comprehensive immunization using co-purified DTaP to decrease the incidence of pertussis. Additionally, these findings offer evidence supporting the modification of China's pertussis vaccination approach.

Analysis of a Sabin-Strain Inactivated Poliovirus Vaccine Response to a Circulating Type 2 Vaccine-Derived Poliovirus Event in Sichuan Province, China 2019-2021

IMPORTANCE

The Sabin-strain inactivated poliovirus vaccine (IPV) may be a tool for polio outbreak response in certain situations.

OBJECTIVE

To investigate the response to a type 2 vaccine-derived poliovirus (VDPV2) outbreak.

DESIGN, SETTING, AND PARTICIPANTS

This case series was conducted in China after a VDPV2 was detected in stool specimens from a child with acute flaccid paralysis (AFP) in Sichuan Province in 2019, 3 years after the global withdrawal of live, attenuated type 2 oral poliovirus vaccine (OPV). Investigation followed National Health Commission and World Health Organization guidance and included searching hospitals for unreported AFP cases; testing stool specimens from the child, his contacts, and local children; enhanced environmental surveillance for VDPV2s in wastewater; and measuring vaccination coverage. Sabin-strain IPV campaigns were conducted in a wide geographic area.

MAIN OUTCOMES AND MEASURES

Any VDPV2 detection after completion of the supplementary immunization activities.

RESULTS

A 28-nucleotide-change VDPV2 was isolated from a young boy. Three VDPV2s were detected in healthy children; 2 were contacts of the original child, and none had paralysis. A search of 31 million hospital records found 10 unreported AFP cases; none were polio. No type 2 polioviruses were found in wastewater. Prior to the event, polio vaccine coverage was 65% among children younger than 5 years. Sabin-strain IPV campaigns reached more than 97% of targeted children, administering 1.4 million doses. No transmission source was identified. More than 1 year of enhanced poliovirus environmental and AFP surveillance detected no additional VDPVs.

CONCLUSIONS AND RELEVANCE

These findings suggest that the circulating VPDV2 outbreak in 2019 was associated with low vaccine coverage. An investigation discovered 3 infected but otherwise healthy children and no evidence of the virus in wastewater. Following Sabin-strain IPV-only campaigns expanding from county to prefecture, the poliovirus was not detected, and the outbreak response was considered by an expert panel and the World Health Organization to have been successful. This success suggests that the Sabin-strain IPV may be a useful tool for responding to circulating VDPV2 outbreaks when high-quality supplementary immunization activities can be conducted and carefully monitored in settings with good sanitation.

Factors associated with neutralizing antibody levels induced by two inactivated COVID-19 vaccines for 12 months after primary series vaccination

Background

BBIBP-CorV and CoronaVac inactivated COVID-19 vaccines are widely-used, World Health Organization-emergency-listed vaccines. Understanding antibody level changes over time after vaccination is important for booster dose policies. We evaluated neutralizing antibody (nAb) titers and associated factors for the first 12 months after primary-series vaccination with BBIBP-CorV and CoronaVac.

Methods

Our study consisted of a set of cross-sectional sero-surveys in Zhejiang and Shanxi provinces, China. In 2021, we enrolled 1,527 consenting 18-59-year-olds who received two doses of BBIBP-CorV or CoronaVac 1, 3, 6, 9, or 12 months earlier and obtained blood samples and demographic and medical data. We obtained 6-month convalescent sera from 62 individuals in Hebei province. Serum nAb titers were measured by standard micro-neutralization cytopathic effect assay in Vero cells with ancestral SARS-CoV-2 strain HB01. We used the first WHO International Standard (IS) for anti-SARS-CoV-2 immunoglobulin (NIBSC code 20/136) to standardized geometric mean concentrations (IU/mL) derived from the nAb geometric mean titers (GMT over 1:4 was considered seropositive). We analyzed nAb titer trends using Chi-square and factors related to nAb titers with logistic regression and linear models.

Results

Numbers of subjects in each of the five month-groupings ranged from 100 to 200 for each vaccine and met group-specific target sample sizes. Seropositivity rates from BBIBP-CorV were 98.0% at 1 month and 53.5% at 12 months, and GMTs were 25.0 and 4.0. Respective seropositivity rates from CoronaVac were 90.0% and 62.5%, and GMTs were 20.2 and 4.1. One-, three-, six-, nine-, and twelve-month GMCs were 217.2, 84.1, 85.7, 44.6, and 10.9 IU/mL in BBIBP-CorV recipients and 195.7, 94.6, 51.7, 27.6, and 13.4 IU/mL in CoronaVac recipients. Six-month convalescent seropositivity was 95.2%; GMC was 108.9 IU/mL. Seropositivity and GMCs were associated with age, sex, and time since vaccination.

Conclusions

Neutralizing Ab levels against ancestral SARS-CoV-2 from BBIBP-CorV or CoronaVac vaccination were similar and decreased with increasing time since vaccination; over half of 12-month post-vaccination subjects were seropositive. Seropositivity and GMCs from BBIBP-CorV and CoronaVac six and nine months after vaccination were similar to or slightly lower than in six-month convalescent sera. These real-world data suggest necessity of six-month booster doses.

Safety, immunogenicity, and immune persistence of two inactivated COVID-19 vaccines replacement vaccination in China: An observational cohort study

Background

To mitigate a national shortage of WIBP-CorV COVID-19 vaccine, China’s regulator approved administering BBIBP-CorV after WIBP-CorV for completion of a primary series. In a pragmatic observational study, we compared immunogenicity and safety of a primary series of WIBP-CorV followed by BBIBP-CorV with a primary series of two doses of BBIBP-CorV.

Methods

We invited healthy 18–59-years-old adults who had already received either WIBP-CorV or BBIBP-CorV as their first dose in a primary series to participate in this observational cohort study. Subjects who had received WIBP-CorV as their first dose became the observation group; subjects who had received BBIBP-CorV as their first dose became the control group. All participants received BBIBP-CorV as their second dose. We obtained sera 1, 2, and 6 months after second doses for nAb titer measurement by micro-neutralization cytopathic effect assay with SARS-CoV-2 strain HB01, standardized with WHO International Standard for anti-SARS-CoV-2 immunoglobulin. Safety was assessed for the 7 days after administration of second doses.

Results

Between March and December 2021, 275 subjects were included in the observation group and 133 in the control group. Neutralizing seropositivity (≥1:4) rates were 98.91 % and 99.25 % at 1 month and 53.16 % and 70.69 % at 6 months. One-month geometric mean titers (GMTs) were 21.33 and 22.45; one-month geometric mean concentrations (GMCs) were 227.71 IU/mL and 273.27 IU/mL. One to two months after vaccination, observation group seropositivity rates and titers were not significantly different to the control group’s. Adverse reaction rates were 11.27 % and 18.80 %, all mild or moderate in severity.

Conclusions

Both primary series were immunogenic; immunogenicity of WIBP-CorV followed by BBIBP-CorV was not different than immunogenicity following two doses of BBIBP-CorV for two months after vaccination; safety profiles were acceptable for both regimens. BBIBP-CorV can be used to complete a primary series that started with WIBP-CorV.

Transmission of Severe Acute Respiratory Syndrome Coronavirus 2 to Close Contacts, China, January-February 2020

We estimated the symptomatic, PCR-confirmed secondary attack rate (SAR) for 2,382 close contacts of 476 symptomatic persons with coronavirus disease in Yichang, Hubei Province, China, identified during January 23–February 25, 2020. The SAR among all close contacts was 6.5%; among close contacts who lived with an index case-patient, the SAR was 10.8%; among close-contact spouses of index case-patients, the SAR was 15.9%. The SAR varied by close contact age, from 3.0% for those <18 years of age to 12.5% for those >60 years of age. Multilevel logistic regression showed that factors significantly associated with increased SAR were living together, being a spouse, and being >60 years of age. Multilevel regression did not support SAR differing significantly by whether the most recent contact occurred before or after the index case-patient’s onset of illness (p = 0.66). The relatively high SAR for coronavirus disease suggests relatively high virus transmissibility.

Investment Case for a Comprehensive Package of Interventions Against Hepatitis B in China: Applied Modeling to Help National Strategy Planning

Background

In 2016, the first global viral hepatitis elimination targets were endorsed. An estimated one-third of the world’s population of individuals with chronic hepatitis B virus (HBV) infection live in China and liver cancer is the sixth leading cause of mortality, but coverage of first-line antiviral treatment was low. In 2015, China was one of the first countries to initiate a consultative process for a renewed approach to viral hepatitis. We present the investment case for the scale-up of a comprehensive package of HBV interventions.

Methods

A dynamic simulation model of HBV was developed and used to simulate the Chinese HBV epidemic. We evaluated the impact, costs, and return on investment of a comprehensive package of prevention and treatment interventions from a societal perspective, incorporating costs of management of end-stage liver disease and lost productivity costs.

Results

Despite the successes of historical vaccination scale-up since 1992, there will be a projected 60 million people still living with HBV in 2030 and 10 million HBV-related deaths, including 5.7 million HBV-related cancer deaths between 2015 and 2030. This could be reduced by 2.1 million by highly active case-finding and optimal antiviral treatment regimens. The package of interventions is likely to have a positive return on investment to society of US$1.57 per US dollar invested.

Conclusions

Increases in HBV-related deaths for the next few decades pose a major public health threat in China. Active case-finding and access to optimal antiviral treatment are required to mitigate this risk. This investment case approach provides a real-world example of how applied modeling can support national dialog and inform policy planning.

Changing Epidemiology of Hepatitis A in China: Evidence From Three National Serological Surveys and the National Notifiable Disease Reporting System

BACKGROUND AND AIMS

China has conducted surveillance for hepatitis A since 1990, and hepatitis A was highly-to-intermediately endemic in 1992 when a Chinese hepatitis A vaccine (HepA) was licensed and introduced as a family-pay vaccine. In 2008, HepA was introduced into the Expanded Program on Immunization as a free childhood vaccine.

APPROACH AND RESULTS

Three nationally representative surveys conducted in 1992, 2006, and 2014 assessed hepatitis B serology. The 1992 survey included hepatitis A virus (HAV) serology, and we tested sera from the 2006 and 2014 surveys for HAV antibodies. We used surveillance, seroprevalence, and vaccination status data to describe the changing epidemiology of hepatitis A in China from 1990 through 2014. Before HepA licensure, anti-HAV seroprevalence was 60% at 4 years of age, 70% at 10 years, and 90% at 59 years; incidence was 52/100,000 and peaked at 4 years. In 2006, after >10 years of private sector vaccination, HepA coverage was <30% among children <5 years, and incidence was 5.4/100,000 with a peak at 10 years. In 2014, coverage was >90% among children under 5 years; incidence was 1.9/100,000. Individuals born before the national introduction of HepA (1988-2004) had lower anti-HAV seroprevalence than earlier and later birth cohorts.

CONCLUSIONS

The incidence of hepatitis A declined markedly following HepA introduction and improvement of sanitation and hygiene. The emerging epidemiology is consistent with disease-induced immunity having been replaced by vaccine-induced immunity, resulting in a low incidence of hepatitis A. Catch-up HepA campaigns to close the immunity gap among the 1998-2004 birth cohorts should be considered.

Evaluating vaccination policies to accelerate measles elimination in China: a meta-population modelling study

BACKGROUND

Measles is among the most highly infectious human diseases. By virtue of increasingly effective childhood vaccination, together with targeted supplemental immunization activities (SIAs), health authorities in the People's Republic of China have reduced measles' reproduction number from about 18 to 2.3. Despite substantial residual susceptibility among young adults, more in some locales than others, sustained routine childhood immunization likely would eliminate measles eventually. To support global eradication efforts, as well as expedite morbidity and mortality reductions in China, we evaluated alternative SIAs via mechanistic mathematical modelling.

METHODS

Our model Chinese population is stratified by immune status (susceptible to measles infection; infected, but not yet infectious; infectious; and recovered or immunized), age (0, 1-4, 5-9, …, 65+ years) and location (31 provinces). Contacts between sub-populations are either empirical or a mixture of preferential and proportionate with respect to age and decline exponentially with distance between locations at age-dependent rates. We estimated initial conditions and most parameters from recent cross-sectional serological surveys, disease surveillance and demographic observations. Then we calculated the reproduction numbers and gradient of the effective number with respect to age- and location-specific immunization rates. We corroborated these analytical results by simulating adolescent and young adult SIAs using a version of our model in which the age-specific contact rates vary seasonally.

RESULTS

Whereas the gradient indicates that vaccinating young adults generally is the optimal strategy, simulations indicate that a catch-up campaign among susceptible adolescent schoolchildren would accelerate elimination, with timing dependent on uptake.

CONCLUSIONS

These results are largely due to indirect effects (i.e. fewer infections than immunized people might otherwise cause), which meta-population models with realistic mixing are uniquely capable of reproducing accurately.

Review of the status and challenges associated with increasing influenza vaccination coverage among pregnant women in China

Influenza vaccination coverage in pregnant women in China remains low. In this review, we first provide an overview of the evidence for the use of influenza vaccination during pregnancy. Second, we discuss influenza vaccination policy and barriers to increased seasonal influenza vaccination coverage in pregnant women in China. Third, we provide case studies of successes and challenges of programs for increasing seasonal influenza vaccination in pregnant women from other parts of Asia with lessons learned for China. Finally, we assess opportunities and challenges for increasing influenza vaccination coverage among pregnant women in China.

The Global Vaccine Action Plan - insights into its utility, application, and ways to strengthen future plans

BACKGROUND

The pace of global progress must increase if the Global Vaccine Action Plan (GVAP) goals are to be achieved by 2020. We administered a two-phase survey to key immunization stakeholders to assess the utility and application of GVAP, including how it has impacted country immunization programs, and to find ways to strengthen the next 10-year plan.

METHODS

For the Phase I survey, an online questionnaire was sent to global immunization stakeholders in summer 2017. The Phase II survey was sent to regional and national immunization stakeholders in summer 2018, including WHO Regional Advisors on Immunization, Expanded Programme on Immunization managers, and WHO and UNICEF country representatives from 20 countries. Countries were selected based on improvements (10) versus decreases (10) in DTP3 coverage from 2010 to 2016.

RESULTS

Global immunization stakeholders (n = 38) cite global progress in improving vaccine delivery (88%) and engaging civil society organizations as advocates for vaccines (83%). Among regional and national immunization stakeholders (n = 58), 70% indicated reaching mobile and underserved populations with vaccination activities as a major challenge. The top ranked activities for helping country programs achieve progress toward GVAP goals include improved monitoring of vaccination coverage and upgrading disease surveillance systems. Most respondents (96%) indicated GVAP as useful for determining immunization priorities and 95% were supportive of a post-2020 GVAP strategy.

CONCLUSIONS

Immunization stakeholders see GVAP as a useful tool, and there is cause for excitement as the global immunization community looks toward the next decade of vaccines. The next 10-year plan should attempt to increase political will, align immunization activities with other health system agendas, and address important issues like reaching mobile/migrant populations and improving data reporting systems.

Progress in Vaccine-Preventable and Respiratory Infectious Diseases-First 10 Years of the CDC National Center for Immunization and Respiratory Diseases, 2006-2015

The need for closer linkages between scientific and programmatic areas focused on addressing vaccine-preventable and acute respiratory infections led to establishment of the National Center for Immunization and Respiratory Diseases (NCIRD) at the Centers for Disease Control and Prevention. During its first 10 years (2006–2015), NCIRD worked with partners to improve preparedness and response to pandemic influenza and other emergent respiratory infections, provide an evidence base for addition of 7 newly recommended vaccines, and modernize vaccine distribution. Clinical tools were developed for improved conversations with parents, which helped sustain childhood immunization as a social norm. Coverage increased for vaccines to protect adolescents against pertussis, meningococcal meningitis, and human papillomavirus–associated cancers. NCIRD programs supported outbreak response for new respiratory pathogens and oversaw response of the Centers for Disease Control and Prevention to the 2009 influenza A(H1N1) pandemic. Other national public health institutes might also find closer linkages between epidemiology, laboratory, and immunization programs useful.

The effect of heterogeneity in uptake of the measles, mumps, and rubella vaccine on the potential for outbreaks of measles: a modelling study

BACKGROUND

Vaccination programmes to prevent outbreaks after introductions of infectious people aim to maintain the average number of secondary infections per infectious person at one or less. We aimed to assess heterogeneity in vaccine uptake and other characteristics that, together with non-random mixing, could increase this number and to evaluate strategies that could mitigate their impact.

METHODS

Because most US children attend elementary school in their own neighbourhoods, surveys of children entering elementary school (age 5 years before Sept 1) allow assessment of spatial heterogeneity in the proportion of children immune to vaccine-preventable diseases. We used data from a 2008 school-entry survey by the Immunization Division of the California Department of Public Health to obtain school addresses; numbers of students enrolled; proportions of enrolled students who had received one or two doses of the measles, mumps, and rubella (MMR) vaccine; and proportions with medical or personal-belief exemptions. Using a mixing model suitable for spatially-stratified populations, we projected the expected numbers of secondary infections per infectious person for measles, mumps, and rubella. We also mapped contributions to this number for measles in San Diego County's 638 elementary schools and its largest district, comprising 200 schools (31%). We then modelled the effect on measles' realised reproduction number (RV) of the following plausible interventions: vaccinating all children with personal-belief exemptions, increasing uptake by 10% to 50% in all low-immunity schools (<90% of students immune) or in only influential (effective daily contact rates >3 or contacts inter-school >30%) low-immunity schools, and increasing private school uptake to the public school average.

FINDINGS

In 2008, 39 132 children began elementary school in San Diego County, CA, USA. At entry to school, 97% had received at least one dose of the MMR vaccine, with 2·5% having personal-belief exemptions. We note substantial heterogeneity in immunity throughout the county. Although the average population immunities for measles, mumps, and rubella (92%, 87%, 92%) were similar to the population-immunity thresholds in homogeneous, randomly-mixing populations (91%, 88%, 76%), after accounting for heterogeneity and non-random mixing, the basic reproduction numbers increased by 70%, meaning that introduced pathogens could cause outbreaks. The impact of our modelled interventions ranged from negligible to a nearly complete reduction in the outbreak potential of measles. The most effective intervention to lower the realised reproduction number (RV 3·39) was raising immunity by 50% in 114 schools with low immunity (RV 1·02), but raising immunity by this level in only influential, low-immunity schools also was effective (RV 2·02). The effectiveness of vaccinating the 972 children with personal-belief exemptions was similar to that of targeting all low-immunity schools (RV 1·11). Targeting only private schools had little effect.

INTERPRETATION

Our findings suggest that increasing vaccine uptake could prevent outbreaks such as that of measles in San Diego in 2008. Vaccinating children with personal-belief exemptions was one of the most effective interventions that we modelled, but further research on mixing in heterogeneous populations is needed.

FUNDING

None.

Vaccination coverage among U.S. adolescents aged 13-17 years eligible for the Vaccines for Children program, 2009

OBJECTIVES

We compared (1) characteristics of adolescents who are and are not entitled to receive free vaccines from the Vaccines for Children (VFC) program and (2) vaccination coverage with meningococcal conjugate (MCV4), quadrivalent human papillomavirus (HPV4), and tetanus-diphtheria-acellular pertussis (Tdap) vaccines among VFC-eligible and non-VFC-eligible adolescents.

METHODS

We analyzed data from the 2009 National Immunization Survey-Teen, a nationally representative, random-digit-dialed survey of households with adolescents aged 13-17 years (n = 20,066). Differences in sociodemographic characteristics and provider-reported vaccination coverage were evaluated using t-tests.

RESULTS

Overall, 32.1% (+/- 1.2%) of adolescents were VFC-eligible. VFC-eligible adolescents were significantly less likely than non-VFC-eligible adolescents to be white and to live in suburban areas, and more likely to live in poverty and to have younger and less educated mothers. Nationally, coverage among non-VFC-eligible adolescents was 57.1% (+/-1.5%) for > or = 1 dose of Tdap, 55.4% (+/-1.5%) for > or = 1 dose of MCV4, and 43.2% (+/- 2.2%) for > or = 1 dose of HPV4. Coverage among VFC-eligible adolescents was 52.5% (+/- 2.4%) for > or = 1 dose of Tdap, 50.1% (+/- 2.4%) for > or = 1 dose of MCV4, and 46.6% (+/- 3.5%) for > or =1 dose of HPV4. Only 27.5% (+/- 1.8%) of non-VFC-eligible adolescents and 25.0% (+/- 2.9%) of VFC-eligible adolescents received > or = 3 doses of HPV4. Vaccination coverage was significantly higher among non-VFC-eligible adolescents for Tdap and MCV4, but not for one-dose or three-dose HPV4. Conclusions. Coverage with some recommended vaccines is lower among VFC-eligible adolescents compared with non-VFC-eligible adolescents. Continued monitoring of adolescent vaccination rates, particularly among VFC-eligible populations, is needed to ensure that all adolescents receive all routinely recommended vaccines.

Vaccination coverage among U.S. children aged 19-35 months entitled by the Vaccines for Children program, 2009

OBJECTIVES

Following the measles outbreaks of the late 1980s and early 1990s, vaccination coverage was found to be low nationally, and there were pockets of underimmunized children primarily in inner cities. We described the percentage and demographics of children who were entitled to the Vaccines for Children (VFC) program in 2009 and evaluated whether Healthy People 2010 (HP 2010) vaccination coverage objectives of 90% were achieved among these children.

METHODS

We analyzed data from 16,967 children aged 19-35 months sampled by the National Immunization Survey in 2009. VFC-entitled children included children who were (1) on Medicaid, (2) not covered by health insurance, (3) of American Indian/Alaska Native race/ethnicity, or (4) covered by private health insurance that did not pay all of the costs of vaccines, but who were vaccinated at a Federally Qualified Health Center or a Rural Health Center.

RESULTS

An estimated 49.7% of all children aged 19-35 months were entitled to VFC vaccines. Compared with children who did not qualify for VFC, the VFC-entitled children were significantly more likely to be Hispanic or non-Hispanic black; to have a mother who was widowed, divorced, separated, or never married; and to live in a household with an annual income below the federal poverty level. Mothers of VFC-entitled children were significantly less likely to have some college experience or to be college graduates. Of nine vaccines analyzed, two vaccines--polio at 91.7% and hepatitis B at 92.2%--achieved the HP 2010 90% coverage objective for VFC-entitled children, and four others, including measles-mumps-rubella at 88.8%, achieved greater than 80% coverage. Conclusions. Today, children with demographic characteristics like those of children who were at the epicenter of the measles outbreaks two decades ago are entitled to VFC vaccines at no cost, and have achieved high vaccination coverage levels.

Perspective of vaccine manufacturers on financing pediatric and adolescent vaccines in the United States

OBJECTIVE

The goal was to understand vaccine manufacturers' perspectives on vaccine financing as a barrier to immunization.

METHODS

Individual telephone interviews with representatives of the 6 manufacturers that produce routinely recommended vaccines for children and adolescents in the United States were conducted in November and December 2006.

RESULTS

Although manufacturers acknowledged that the price of newer vaccines presents challenges to optimal vaccine use, they asserted that children and adolescents have access to vaccinations through public and private insurance. Respondents suggested that the system could be improved through adequate funding of the public-sector safety net. Respondents stated that providers should receive timely reimbursement for the full costs of vaccine purchase and administration, and manufacturers who sell directly to health care providers may provide flexible payment terms for vaccine purchases. Manufacturers supported targeted expansion of the Vaccines for Children program to allow children with incomplete insurance coverage for vaccines to receive vaccines at health department clinics. Manufacturers perceived delays in publication of Advisory Committee on Immunization Practices recommendations as a potential barrier to vaccine uptake. They viewed the perceived lack of public value for vaccines as a potential barrier to adequate reimbursement and optimal utilization. Respondents also maintained that their ability to negotiate vaccine prices through the private market is a crucial priority.

CONCLUSIONS

Manufacturers assert that children and adolescents have access to immunizations through public and private insurance. Manufacturers think that they have mitigated the challenge most directly in their control: the large financial outlays required for up-front vaccine purchases.

Underinsurance and pediatric immunization delivery in the United States

BACKGROUND

Underinsured children are covered by private health insurance that does not cover the cost of vaccines, are not entitled to receive publicly purchased vaccines at no cost through the Vaccines for Children (VFC) Program unless they receive doses at a Federally Qualified Health Center (FQHC) or a Rural Health Center (RHC), may be referred by their primary care providers to health department clinics (HDCs) for vaccinations, and may have lower vaccination coverage for new and more expensive vaccines.

OBJECTIVES

To describe the estimated percentage of children in the U.S. who are underinsured, receive vaccine doses at HDCs, and are not VFC-entitled; and to evaluate the association between being underinsured, receiving vaccine doses at an HDC, and timely vaccination coverage.

METHODS

Subjects were 16,621 19-35 month-old children sampled by the National Immunization Survey in 2007.

RESULTS

Of all 19-35 month-old children, an estimated 10.5% were underinsured; and an estimated 1.4% were underinsured, received doses at an HDC, and were not VFC-entitled. Compared to fully insured children, children who were underinsured and received doses at an HDC had significantly lower vaccination coverage for the varicella (81.5% vs. 87.7%, p < 0.05) and PCV7 (55.1% vs. 75.9%, p < 0.05) vaccines.

CONCLUSIONS

Children who were underinsured and received doses at HDCs were found to have lower estimated timely vaccination coverage for recently recommended vaccines and more expensive varicella and PCV7 vaccines. To adequately vaccinate these children at HDCs, states require stable funding to pay for vaccines as the number of new and more expensive vaccines grows.

Underinsurance and adolescent immunization delivery in the United States

OBJECTIVE

The goal was to explore the association of being underinsured and receiving doses at a health department clinic (HDC) with not receiving all recommended adolescent vaccine doses.

METHODS

A total of 5657 adolescents, 13 to 17 years of age, were sampled in the National Immunization Survey-Teen in 2006-2007.

RESULTS

A total of 63.9% of all adolescents were covered by private health insurance. Among privately insured adolescents, approximately 31.3% were underinsured. Compared with fully insured adolescents, underinsured adolescents were more likely to receive doses at an HDC for tetanus-diphtheria toxoids/tetanus toxoids-reduced diphtheria toxoids-acellular pertussis vaccine (25.1% vs 6.2%; P < .05), tetravalent meningococcal conjugate vaccine (11.5% vs 2.5%; P < .05), and quadrivalent human papillomavirus vaccine (16.2% vs 3.4%; P < .05). Also, compared with fully insured adolescents, underinsured adolescents who received doses at an HDC had lower estimated rates of vaccination coverage for tetanus-diphtheria toxoids/tetanus toxoids-reduced diphtheria toxoids-acellular pertussis vaccine (58.5% vs 70.9%; P < .05), tetravalent meningococcal conjugate vaccine (10.8% vs 25.8%; P < .05), and quadrivalent human papillomavirus vaccine (7.8% vs 14.3%; P < .05).

CONCLUSION

Underinsured adolescents who receive doses at an HDC have lower rates of vaccination coverage than do fully insured adolescents.

Financing the delivery of vaccines to children and adolescents: challenges to the current system

Recent increases in the number and costs of vaccines routinely recommended for children and adolescents have raised concerns about the ability of the current vaccine financing and delivery systems to maintain access to recommended vaccines without financial barriers. Here we review the current state of US financing for vaccine delivery to children and adolescents and identify challenges that should be addressed to ensure future access to routinely recommended vaccines without financial barriers. Challenges were considered from the perspectives of vaccine providers; state and local governments; insurers, employers, and other health care purchasers; vaccine manufacturers; and consumers.

Immunization programs for infants, children, adolescents, and adults: clinical practice guidelines by the Infectious Diseases Society of America

Evidence-based guidelines for immunization of infants, children, adolescents, and adults have been prepared by an Expert Panel of the Infectious Diseases Society of America (IDSA). These updated guidelines replace the previous immunization guidelines published in 2002. These guidelines are prepared for health care professionals who care for either immunocompetent or immunocompromised people of all ages. Since 2002, the capacity to prevent more infectious diseases has increased markedly for several reasons: new vaccines have been licensed (human papillomavirus vaccine; live, attenuated influenza vaccine; meningococcal conjugate vaccine; rotavirus vaccine; tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis [Tdap] vaccine; and zoster vaccine), new combination vaccines have become available (measles, mumps, rubella and varicella vaccine; tetanus, diphtheria, and pertussis and inactivated polio vaccine; and tetanus, diphtheria, and pertussis and inactivated polio/Haemophilus influenzae type b vaccine), hepatitis A vaccines are now recommended universally for young children, influenza vaccines are recommended annually for all children aged 6 months through 18 years and for adults aged > or = 50 years, and a second dose of varicella vaccine has been added to the routine childhood and adolescent immunization schedule. Many of these changes have resulted in expansion of the adolescent and adult immunization schedules. In addition, increased emphasis has been placed on removing barriers to immunization, eliminating racial/ethnic disparities, addressing vaccine safety issues, financing recommended vaccines, and immunizing specific groups, including health care providers, immunocompromised people, pregnant women, international travelers, and internationally adopted children. This document includes 46 standards that, if followed, should lead to optimal disease prevention through vaccination in multiple population groups while maintaining high levels of safety.

A comprehensive immunization strategy to eliminate transmission of hepatitis B virus infection in the United States: recommendations of the Advisory Committee on Immunization Practices (ACIP) Part II: immunization of adults

Hepatitis B vaccination is the most effective measure to prevent hepatitis B virus (HBV) infection and its consequences, including cirrhosis of the liver, liver cancer, liver failure, and death. In adults, ongoing HBV transmission occurs primarily among unvaccinated persons with behavioral risks for HBV transmission (e.g., heterosexuals with multiple sex partners, injection-drug users [IDUs], and men who have sex with men [MSM]) and among household contacts and sex partners of persons with chronic HBV infection. This report, the second of a two-part statement from the Advisory Committee on Immunization Practices (ACIP), provides updated recommendations to increase hepatitis B vaccination of adults at risk for HBV infection. The first part of the ACIP statement, which provided recommendations for immunization of infants, children, and adolescents, was published previously (CDC. A comprehensive immunization strategy to eliminate transmission of hepatitis B virus infection in the United States: recommendations of the Advisory Committee on Immunization Practices [ACIP]. Part 1: immunization of infants, children, and adolescents. MMWR 2005;54[No. RR-16]:1-33). In settings in which a high proportion of adults have risks for HBV infection (e.g., sexually transmitted disease/human immunodeficiency virus testing and treatment facilities, drug-abuse treatment and prevention settings, health-care settings targeting services to IDUs, health-care settings targeting services to MSM, and correctional facilities), ACIP recommends universal hepatitis B vaccination for all unvaccinated adults. In other primary care and specialty medical settings in which adults at risk for HBV infection receive care, health-care providers should inform all patients about the health benefits of vaccination, including risks for HBV infection and persons for whom vaccination is recommended, and vaccinate adults who report risks for HBV infection and any adults requesting protection from HBV infection. To promote vaccination in all settings, health-care providers should implement standing orders to identify adults recommended for hepatitis B vaccination and administer vaccination as part of routine clinical services, not require acknowledgment of an HBV infection risk factor for adults to receive vaccine, and use available reimbursement mechanisms to remove financial barriers to hepatitis B vaccination.

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.

Vaccine supply problems: a perspective of the Centers for Disease Control and Prevention

Although immunization is one of the great public health achievements, continued success depends on an available supply of the vaccines that are recommended for routine use. Beginning in 2000, the United States experienced vaccine supply disruptions of unprecedented scope and magnitude. Although most of the supply disruptions have been resolved, it appears that a fragile vaccine supply will be part of the immunization environment in the United States for the foreseeable future. Here, we describe the perspective of the Centers for Disease Control and Prevention on the recent supply disruptions and the methods used to manage vaccine shortages. The present article focuses on routine pediatric vaccines, including influenza virus vaccine.

The association between having a medical home and vaccination coverage among children eligible for the vaccines for children program

BACKGROUND

The Vaccines for Children (VFC) program is designed to reduce the cost of vaccines for vulnerable children, including Medicaid-eligible children, American Indian/Alaska Native children, uninsured children, and underinsured children whose health insurance does not cover the cost of vaccinations. A desired consequence of the program is to promote comprehensive continuous medical care within a medical home for these children.

OBJECTIVES

To explore how having a medical home is associated with vaccination coverage among children eligible for the program.

PARTICIPANTS

A total of 24514 children 19 to 35 months of age sampled by the National Immunization Survey.

DESIGN

VFC eligibility was evaluated for 24514 children 19 to 35 months of age who were sampled by the National Immunization Survey. Children were considered to have a medical home if they had a doctor, nurse, or physician's assistant who provided them with ongoing routine care, including well-child care, preventive care, and sick care, according to their parents. Sampled children were determined to be 4:3:1:3:3 up-to-date (UTD) if their vaccination providers reported administering >or=4 doses of diphtheria-tetanus toxoids-acellular pertussis vaccine, >or=3 doses of polio vaccine, >or=1 dose of measles-mumps-rubella vaccine, >or=3 doses of Haemophilus influenzae type b vaccine, and >or=3 doses of hepatitis B vaccine.

RESULTS

Nationally, 44.9% of all children were VFC eligible and 93.0% of the VFC-eligible children received all vaccine doses at a provider enrolled in the VFC program. Compared with children who were not VFC eligible, VFC-eligible children were less likely to be UTD (70.8% vs 77.7%) and less likely to have a medical home (82.1% vs 95.0%). However, among VFC-eligible children, children who had a medical home were significantly more likely to be UTD, compared with children who did not have a medical home (72.3% vs 63.5%). Also, among VFC-eligible children who had a medical home, children who used their medical home consistently to receive all of their vaccination doses were significantly more likely to be UTD, compared with children who did not receive all of their doses from their medical home (75.3% vs 65.7%). Finally, the 4:3:1:3:3 vaccination coverage rate among VFC-eligible children who received all of their vaccination doses from their medical home was not significantly different from that among non-VFC-eligible children, after controlling for significant differences in sociodemographic factors between these groups (adjusted difference: 2.8%; 95% confidence interval: -0.1% to 5.7%).

CONCLUSIONS

Although the vaccination coverage rate among VFC-eligible children who had a medical home and received all vaccine doses from their medical home was essentially equivalent to that of non-VFC-eligible children, substantial percentages of VFC-eligible children either did not have a medical home or did not use their medical home to receive all of their recommended vaccinations. The vaccination coverage rate among these children was significantly lower. This suggests that there may be opportunities to increase vaccination coverage by removing barriers that prevent the adoption and consistent use of a medical home among these children.

Immunizations In The United States: Success, Structure, And Stress

Immunization is a great success of preventive medicine. In the United States, most vaccine-preventable diseases of childhood are at or near record lows while the number of diseases preventable by vaccination has increased. These successes result from a comprehensive system that includes basic research; developing and testing vaccine candidates; a manufacturing base; a regulatory authority; development of immunization policies; implementation of immunization recommendations; and a compensation system for the few people unavoidably injured by vaccines. Despite the successes, the system faces numerous challenges, including vaccine supply, cost, and safety; adult immunization; vaccine research and development; and biopreparedness.

Insurance status and vaccination coverage among US preschool children

BACKGROUND

Insurance status has been shown to have an impact on children's use of preventive and acute health services. The objective of this study was to determine the relationship between insurance status and vaccination coverage among US preschool children aged 19 to 35 months.

METHODS

We linked data from 2 national telephone surveys, the National Immunization Survey and the National Survey of Early Childhood Health, conducted during the first half of 2000. Children were considered up to date (UTD) when they had received at least 4 diphtheria-tetanus-acellular pertussis/diphtheria-tetanus-pertussis vaccines, 3 poliovirus vaccines, 1 MMR vaccine, 3 Haemophilus influenza vaccines, and 3 hepatitis B vaccines at the time the interview was conducted.

RESULTS

Among the 735 children in our study sample, 72% were UTD. The vast majority (94%) reported some type of health insurance at the time of the survey. Children with private insurance were more likely to be UTD (80%) than those with public insurance (56%) or no insurance (64%). In a multivariate analysis that controlled for child's race/ethnicity; household income; maternal age/marital status/educational level; location of usual care; and Special Supplemental Nutrition Program for Women, Infants, and Children participation, insurance was no longer an independent predictor of vaccination.

CONCLUSIONS

The disparity in vaccination coverage among publicly, privately, and uninsured children is dramatic, underscoring its importance as a marker for underimmunization, despite the multivariate findings. The Vaccines for Children Program, a partnership between public health and vaccination providers who serve uninsured children and those enrolled in Medicaid, is well suited to target and improve vaccination coverage among these vulnerable children.

Impact of vaccine shortages on immunization programs and providers

BACKGROUND

During 2001 and the first half of 2002, the United States experienced severe shortages of five of the eight universally recommended vaccines for children.

OBJECTIVES

To evaluate the impact of shortages of diphtheria-tetanus-acellular pertussis vaccine (DTaP), pneumococcal conjugate vaccine (PCV7), and tetanus and diphtheria vaccine (Td) shortages on state and urban area immunization programs and immunization providers between September 2001 and January 2002.

METHODS

(1) Survey of state and urban area immunization program managers. Outcome measures included changes in vaccine distribution and suspension of daycare/Head Start and school entry immunization requirements for Td, DTaP, and PCV7. (2) Interviews with Vaccines for Children Program immunization providers scheduled to receive a routine site visit between January 21 and February 1, 2002. Outcome measures included problems experienced with vaccine orders, implementation of Advisory Committee on Immunization Practices (ACIP) interim recommendations for DTaP and PCV7, and length of time with no DTaP or PCV7 vaccines in stock.

RESULTS

Over 85% of immunization programs changed the way they distributed PCV7, DTaP, and Td vaccines to providers, including limiting the amount of vaccine ordered or distributing partial orders. Additionally, 76% of programs experienced problems purchasing or receiving varicella vaccine. Sixty-eight percent of programs suspended school entry requirements for Td. Immunization providers reported problems with orders of Td (56%), PCV7 (45%), DTaP (30%), and varicella (29%). Approximately 16% and 29% of providers implemented the interim ACIP recommendations for DTaP and PCV7, respectively. However, 21% of providers suspended administration of all doses of PCV7 because they ran out of vaccine before learning of the shortage.

CONCLUSIONS

From suspension of school entry requirements to delaying administration of vaccine, the recent vaccine shortages affected immunization programs' and providers' ability to administer vaccines in a timely manner.

Counting the shots: a model for immunization screening and referral in nonmedical settings

BACKGROUND

Clinics of the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) have become important partners in efforts to improve vaccination coverage in low income children. However, the time required to assess all antigens in each child's vaccination record may exceed the capacity of many of these clinics. Seeking a solution, experts recommended assessing up-to-date (UTD) status only for the diphtheria-tetanus-acellular-pertussis (DTaP) vaccine and treating this as a proxy measure for all vaccines in the childhood schedule. Whether this single vaccine screening method represents an acceptable alternative to the traditional multiple-vaccine method as a basis for improving overall immunization coverage levels in this vulnerable population has not been demonstrated.

OBJECTIVE

To evaluate the validity of the proposed simplified method for assessing immunization status in a nationally representative population of infants and children who had ever been enrolled in WIC before 35 months old.

METHODS

This was a cross-sectional analysis of the 2000 National Immunization Survey representing children ages 3 to 24 months who had ever been enrolled in WIC. For the 6277 children in the study population, we compared personal records of completion status for DTaP with personal records of completion status for all immunizations appropriate for age in the combination 4:3:1:3 schedule to see which of the 2 (single vs multiple screening) methods would better predict the child's true (provider-reported) status for the 4:3:1:3 series. The main outcome measures were the comparative sensitivity, specificity, and overall test efficiency of the 2 methods in correctly identifying underimmunized WIC children.

RESULTS

Completion status for DTaP was less sensitive than completion status for all vaccinations in correctly identifying truly underimmunized children (sensitivity = 70% and 77%, respectively). However, it was more specific in correctly identifying children who were truly UTD for age (specificity = 86% and 82%, respectively). The 2 methods were essentially identical with respect to overall test efficiency (82% and 81% for DTaP assessment and assessment of all vaccines, respectively).

CONCLUSIONS

Given limited resources to do immunization screening and referral in nonmedical settings such as WIC, simplifying the process by using DTaP from the personal vaccination record as a proxy for the 4:3:1:3 series is a viable option. Loss in sensitivity may well be offset by gains in the capacity of WIC clinics to screen more children.

Immunization status among children newly enrolled in a health plan: a new frontier for quality measurement?

BACKGROUND

The National Scientific Panel on Immunization Measurement Standards recently recommended that the assessment population for the childhood immunization measure of the Health Plan Employer Data and Information Set include 24-month-olds with > or = 6 months of continuous enrollment in a health plan. The current inclusion criterion is > or = 12 months of continuous enrollment. The new recommendation would expand the assessment population to include children with more recent enrollment.

OBJECTIVES

To compare the immunization status of children enrolled in a large health plan between ages 12 and 17 months vs earlier in life and to describe the proportion of children enrolled between ages 12 and 17 months that could be fully immunized by 24 months.

METHODS

All children enrolled in a group-model HMO who turned 24 months old during a 12-month study were identified for a retrospective cohort study. A computerized immunization database was used to identify all vaccines administered to each child, and summary measures were created to describe immunization status at selected times. The full-text medical records of children who seemed to have no immunizations in the computerized database were reviewed.

RESULTS

Of the 3448 children in the study population, 3130 (91%) enrolled between birth and 11 months of age and 161 (5%) enrolled between 12 and 17 months of age. Whereas 87% of children who enrolled between birth and 11 months of age were fully immunized at age 24 months, only 57% of those enrolled between 12 and 17 months of age were fully immunized at 24 months of age (risk difference, 30%; 95% confidence interval, 24%-36%; P < .001). Of the 161 children enrolled between 12 and 17 months of age, 68% had received all of the immunizations in the primary series. Only 6% of these 161 children would have been impossible or difficult to fully immunize by age 24 months using accelerated catch-up vaccination schedules.

CONCLUSIONS

Children who enrolled in an HMO between 12 and 17 months of age were less likely than those who enrolled earlier in life to be fully immunized by age 24 months, but it would be feasible to bring almost all of them up to date by that age. Including such children in immunization measures, either together with earlier-enrolled children or as a separate stratum, would expand the scope of the quality of care under evaluation.

Reducing geographic, racial, and ethnic disparities in childhood immunization rates by using reminder/recall interventions in urban primary care practices

CONTEXT

An overarching national health goal of Healthy People 2010 is to eliminate disparities in leading health care indicators including immunizations. Disparities in US childhood immunization rates persist, with inner-city, black, and Hispanic children having lower rates. Although practice or clinic-based interventions, such as patient reminder/recall systems, have been found to improve immunization rates in specific settings, there is little evidence that those site-based interventions can reduce disparities in immunization rates at the community level.

OBJECTIVE

To assess the effect of a community-wide reminder, recall, and outreach (RRO) system for childhood immunizations on known disparities in immunization rates between inner-city versus suburban populations and among white, black, and Hispanic children within an entire county.

SETTING

Monroe County, New York (birth cohort: 10 000, total population: 750 000), which includes the city of Rochester. Three geographic regions within the county were compared: the inner city of Rochester, which contains the greatest concentration of poverty (among 2-year-old children, 64% have Medicaid); the rest of the city of Rochester (38% have Medicaid); and the suburbs of the county (8% have Medicaid).

INTERVENTIONS

An RRO system was implemented in 8 city practices in 1995 (covering 64% of inner-city children) and was expanded to 10 city practices by 1999 (covering 74% of inner-city children, 61% of rest-of-city children, and 9% of suburban children). The RRO intervention involved lay community-based outreach workers who were assigned to city practices to track immunization rates of all 0- to 2-year-olds, and to provide a staged intervention with increasing intensity depending on the degree to which children were behind in immunizations (tracking for all children, mail, or telephone reminders for most children, assistance with transportation or scheduling for some children, and home visits for 5% of children who were most behind in immunizations and who faced complex barriers).

STUDY PARTICIPANTS

Three separate cohorts of 0- to 2-year-old children were assessed-those residing in the county in 1993, 1996, and 1999.

STUDY DESIGN

Immunization rates were measured for each geographic region in Monroe County at 3 time periods: before the implementation of a systematic RRO system (1993), during early phases of implementation of the RRO system (1996), and after implementation of the RRO system in 10 city practices (1999). Immunization rates were compared for children living in the 3 geographic regions, and for white, black, and Hispanic children. Immunization rates were measured by the same methodology in each of the 3 time periods. A denominator of children was obtained by merging patient lists from the practice files of most pediatric and family medicine practices in the county (covering 85% to 89% of county children). A random sample of children (>500 from the suburbs and >1200 from the city for each sampling period) was then selected for medical chart review at practices to determine demographic characteristics (including race and ethnicity) and immunization rates. City children were oversampled to allow detection of effects by geographic region and race. Rates for the 3 geographic regions and for the entire county were determined using Stata to adjust for the clustered sampling.

MAIN OUTCOME MEASURES

Immunization rates at 12 and 24 months for recommended vaccines (4 diphtheria-tetanus-pertussis:3 polio:1 measles-mumps-rubella: > or =1 Haemophilus influenzae type b on or after 12 months of age).

RESULTS

DISPARITIES BY GEOGRAPHIC REGION: Baseline immunization rates (1993) for 24-month-olds were as follows: inner city (55%), rest of city (64%), and suburbs (73%), with an 18% difference in rates between the inner city and suburbs. By 1996, immunization rates rose faster in the inner city (+21% points) than in the suburbs (+14% points) so that the difference in rates between the inner city and suburbs had narrowed to 11%. In 1999, rates were similar across geographic regions: inner city (84%), rest of city (81%), and suburbs (88%), with a 4% difference between the inner city and suburbs. DISPARITIES BY RACE AND ETHNICITY: Immunization rates were available in 1996 and 1999 by race and ethnicity. Twenty-four-month immunization rates in 1996 showed disparities: white (89%), black (76%), and Hispanic (74%), with a 13% difference between rates for white and black children and a 15% difference between white and Hispanic children. In 1999, rates were similar across the groups: white (88%), black (81%), and Hispanic (87%), with a 7% difference between rates for white and black children, and a 1% difference between white and Hispanic children.

CONCLUSIONS

A community-wide intervention of patient RRO raised childhood immunization rates in the inner city of Rochester and was associated with marked reductions in disparities in immunization rates between inner-city and suburban children and among racial and ethnic minority populations. By targeting a relatively manageable number of primary care practices that serve city children and using an effective strategy to increase immunization rates in each practice, it is possible to eliminate disparities in immunizations for vulnerable children.