Immunogenicity and safety of measles-rubella vaccine co-administered with attenuated Japanese encephalitis SA 14-14-2 vaccine in infants aged 8 months in China: a non-inferiority randomised controlled trial

BACKGROUND

In China, measles-rubella vaccine and live attenuated SA 14-14-2 Japanese encephalitis vaccine (LJEV) are recommended for simultaneous administration at 8 months of age, which is the youngest recommended age for these vaccines worldwide. We aimed to assess the effect of the co-administration of these vaccines at 8 months of age on the immunogenicity of measles-rubella vaccine.

METHODS

We did a multicentre, open-label, non-inferiority, two-group randomised controlled trial in eight counties or districts in China. We recruited healthy infants aged 8 months who had received all scheduled vaccinations according to the national immunisation recommendations and who lived in the county of the study site. Enrolled infants were randomly assigned (1:1) to receive either measles-rubella vaccine and LJEV simultaneously (measles-rubella plus LJEV group) or measles-rubella vaccine alone (measles-rubella group). The primary outcome was the proportion of infants with IgG antibody seroconversion for measles 6 weeks after vaccination, and a secondary outcome was the proportion of infants with IgG antibody seroconversion for rubella 6 weeks after vaccination. Analyses included all infants who completed the study. We used a 5% margin to establish non-inferiority. This trial was registered at ClinicalTrials.gov (NCT02643433).

FINDINGS

1173 infants were assessed for eligibility between Aug 13, 2015, and June 10, 2016. Of 1093 (93%) enrolled infants, 545 were randomly assigned to the measles-rubella plus LJEV group and 548 to the measles-rubella group. Of the infants assigned to each group, 507 in the measles-rubella plus LJEV group and 506 in the measles-rubella group completed the study. Before vaccination, six (1%) of 507 infants in the measles-rubella plus LJEV group and one (<1%) of 506 in the measles-rubella group were seropositive for measles; eight (2%) infants in the measles-rubella plus LJEV group and two (<1%) in the measles-rubella group were seropositive for rubella. 6 weeks after vaccination, measles seroconversion in the measles-rubella plus LJEV group (496 [98%] of 507) was non-inferior to that in the measles-rubella group (499 [99%] of 506; difference -0·8% [90% CI -2·6 to 1·1]) and rubella seroconversion in the measles-rubella plus LJEV group (478 [94%] of 507) was non-inferior to that in the measles-rubella group (473 [94%] of 506 infants; difference 0·8% [90% CI -1·8 to 3·4]). There were no serious adverse events in either group and no evidence of a difference between the two groups in the prevalence of any local adverse event (redness, rashes, and pain) or systemic adverse event (fever, allergy, respiratory infections, diarrhoea, and vomiting). Fever was the most common adverse event (97 [19%] of 507 infants in the measles-rubella plus LJEV group; 108 [21%] of 506 infants in the measles-rubella group).

INTERPRETATION

The evidence of similar seroconversion and safety with co-administered LJEV and measles-rubella vaccines supports the co-administration of these vaccines to infants aged 8 months. These results will be important for measles and rubella elimination and the expansion of Japanese encephalitis vaccination in countries where it is endemic.

FUNDING

US Centers for Disease Control and Prevention, US Department of Health and Human Services; China-US Collaborative Program on Emerging and Re-emerging Infectious Diseases.

The landscape of vaccines in China: history, classification, supply, and price

Background

Vaccine regulation in China meets World Health Organization standards, but China’s vaccine industry and immunization program have some characteristics that differ from other countries. We described the history, classification, supply and prices of vaccines available and used in China, compared with high-and middle-incomes countries to illustrate the development of Chinese vaccine industry and immunization program.

Methods

Immunization policy documents were obtained from the State Council and the National Health and Family Planning Commission (NHFPC). Numbers of doses of vaccines released in China were obtained from the Biologicals Lot Release Program of the National Institutes for Food and Drug Control (NIFDC). Vaccine prices were obtained from Chinese Central Government Procurement (CCGP). International data were collected from US CDC, Public Health England, European CDC, WHO, and UNICEF.

Results

Between 2007 and 2015, the annual supply of vaccines in China ranged between 666 million and 1,190 million doses, with most doses produced domestically. The government’s Expanded Program on Immunization (EPI) prevents 12 vaccine preventable diseases (VPD) through routine immunization. China produces vaccines that are in common use globally; however, the number of routinely-prevented diseases is fewer than in high- and middle-income countries. Contract prices for program (EPI) vaccines ranged from 0.1 to 5.7 US dollars per dose - similar to UNICEF prices. Contract prices for private-market vaccines ranged from 2.4 to 102.9 US dollars per dose - often higher than prices for comparable US, European, and UNICEF vaccines.

Conclusion

China is a well-regulated producer of vaccines, but some vaccines that are important globally are not included in China’s EPI system in China. Sustained and coordinated effort will be required to bring Chinese vaccine industry and EPI into an era of global leadership.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3422-0) contains supplementary material, which is available to authorized users.

Routine immunization services costs and financing in China, 2015

OBJECTIVE

To estimate the costs of routine immunization (RI) services in China in 2015, to provide objective data relevant to investment in the Expanded Program on Immunization, and to contribute to global data on costing and financing of RI.

METHODS

The study was conducted between January and March 2016. We selected 276 villages, 138 townships, 46 counties, and 40 prefectures from 15 provinces as investigation sites at random, stratified by eastern, middle, and western regions. Direct cost items included vaccines, personnel, cold chain, surveillance, communication, training, and supervision at the national, provincial, prefecture, county, township, and village levels. We obtained financial data from governmental and external sources. Indirect costs of RI included parents' transportation costs and productivity lost due to taking their children for vaccination.

RESULTS

Total direct costs were $92.42 for each child fully immunized ($4.20/dose), which equates to $1529.55 million per birth cohort. RI costs were higher in the eastern region than in the western region, and higher than that of the central region. Vaccination coverage was positively associated with direct routine immunization costs. The cost of the recommended vaccines was $19.08/child and vaccine only accounted for 20.64% of total costs. Operational cost, including surveillance, communication, training and supervision, was $217.31/child, accounting for 14.21% of total cost. The indirect cost per child was $72.86; the total indirect cost was $1205.83 million for the birth cohort. Government investment in RI accounted for about 70% of total costs. Revenue from sales of private-sector vaccine supported the remaining 30% of RI costs.

CONCLUSIONS

While government financing has increased, some operating costs continue to be provided from revenue generated by sales of Category 2 (private-sector) vaccines to families. China could benefit from bringing new and underutilized vaccines into the EPI system based on evidence that includes routine immunization vaccine and operations costs.

Knowledge, attitudes, and practices regarding hepatitis B vaccination among hospital-based doctors and nurses in China: Results of a multi-site survey

BACKGROUND

Hepatitis B virus (HBV) can cause chronic HBV infection, which may lead to advanced cirrhosis and liver cancer. Healthcare workers (HCWs) are at risk HBV infection as an occupational hazard. Hepatitis B vaccination of HCWs is recommended by WHO, but the status of hepatitis B vaccination among HCWs in China is seldom reported.

METHODOLOGY

We conducted a cross-sectional study in 22 hospitals of 3 developed cities in China. We interviewed managers in infectious diseases and occupational health departments, and at least 40 HCWs per hospital.

RESULTS

We interviewed 929 HCWs; 80.8% were vaccinated against hepatitis B and 96.7% were willing to be vaccinated; 38.2% of HCWs reported having at least one needle stick or sharps injury. Three hospitals provide free hepatitis B vaccination for HCWs; hospitals with a hepatitis B vaccination policy, more HCWs reported being vaccinated (91.7% vs 79.0%, P < 0.001). HCWs in high risk departments (P = 0.011), with more knowledge of hepatitis B vaccine (P < 0.001), and with fewer working years (P = 0.002) were more likely to be vaccinated against HBV. Infectious diseases and occupational health managers had positive attitudes towards hepatitis B vaccination.

CONCLUSIONS

Hepatitis B vaccination was well accepted among HCWs. Hospital provision of free vaccine, greater HCW knowledge of HBV, and working in higher-risk settings were associated with being vaccinated. A national policy of offering hepatitis B vaccine to HCWs should be considered in China. Provision of free hepatitis B vaccine for HBsAb negative HCWs may be acceptable. Education about HBV and hepatitis B vaccine may help promote policy implementation.

Loss of confidence in vaccines following media reports of infant deaths after hepatitis B vaccination in China

BACKGROUND

China reduced hepatitis B virus (HBV) infection by 90% among children under 5 years old with safe and effective hepatitis B vaccines (HepB). In December 2013, this success was threatened by widespread media reports of infant deaths following HepB administration. Seventeen deaths and one case of anaphylactic shock following HBV vaccination had been reported.

METHODS

We conducted a telephone survey to measure parental confidence in HepB in eleven provinces at four points in time; reviewed maternal HBV status and use of HepB for newborns in birth hospitals in eight provinces before and after the event; and monitored coverage with hepatitis B vaccine and other programme vaccines in ten provinces.

RESULTS

HepB from the implicated company was suspended during the investigation, which showed that the deaths were not caused by HepB vaccination. Before the event, 85% respondents regarded domestic vaccines as safe, decreasing to 26.7% during the event. During the height of the crisis, 30% of parents reported being hesitant to vaccinate and 18.4% reported they would refuse HepB. Use of HepB in the monitored provinces decreased by 18.6%, from 53 653 doses the week before the event to 43 688 doses during the week that Biokangtai HepB was suspended. Use of HepB within the first day of life decreased by 10% among infants born to HBsAg-negative mothers, and by 6% among infants born to HBsAg-positive mothers. Vaccine refusal and HepB birth dose rates returned to baseline within 2 months; confidence increased, but remained below baseline.

CONCLUSIONS

The HBV vaccine event resulted in the suspension of a safe vaccine, which was associated with a decline of parental confidence, and refusal of vaccination. Suspension of a vaccine can lead to loss of confidence that is difficult to recover. Timely and credible investigation, accompanied by proactive outreach to stakeholders and the media, may help mitigate negative impact of future coincidental adverse events following immunization.

Measles transmission among adults with spread to children during an outbreak: Implications for measles elimination in China, 2014

INTRODUCTION

Following implementation of China's 2006-2012 Action Plan for measles elimination, which led to a nadir of measles in 2012, a resurgence started in 2013 that continued into 2014. Measles typically is a disease that mainly affects children. We investigated a community outbreak in 2014 with measles virus transmission among adults without children serving as virus reservoirs. Our investigation highlights adult susceptibility to measles.

METHODS

We conducted a retrospective active case search, and analyzed confirmed case data to describe person, place, and time characteristics of the outbreak. All individuals with measles with onset during the first 2 months of the outbreak were interviewed face-to-face to determine source(s) of infection and transmission route (from whom and to whom).

RESULTS

Among the 280 cases, 220 (77.6%) were among ≥20-year-old adults, 24 (8.6%) were among 8-23 month olds, 22 (7.9%) were among <8-month-old infants, and the remaining 14 (5.9%) were among 2-19 year olds. Of the 83 cases in the early stage of the outbreak, 41 (49.4%) were acquired in the community, 24 (28.9%) were acquired nosocomially, 13 (15.7%) were acquired by family contact, and 5 were imported. Among 44 clearly determined transmission linkages, 37 (84.1%) were adult to other age-group (these include 29 adult-to-adult, seven adult-to-child, and one adult-to-infant), six were from infants to adult and children, and one was child-to-child. Outbreak response immunization activities were implemented by non-selective supplementary immunization activities, with 51.3% of targeted 5-19-year-old children and adolescents, and 30.2% of targeted 20-49-year-old adults being vaccinated.

CONCLUSIONS

Despite high population immunity among children and adolescents following three rounds of measles vaccine supplementary immunization activities, sustained measles virus transmission still occurred among adults in this community. Adult measles immunity gaps might threaten measles elimination, highlighting the importance targeting susceptible adults during outbreak response immunization.

Risk factors for measles infection in 0-7 month old children in China after the 2010 nationwide measles campaign: A multi-site case-control study, 2012-2013

Introduction:

Endemic measles persists in China, despite >95% reported coverage of two measles-containing vaccine doses and nationwide campaign that vaccinated more than 100 million children in 2010. We performed a case–control study in six Chinese provinces during January 2012 through June 2013 to identify risk factors for measles infection among children aged 0–7 months.

Methods:

Children with laboratory-confirmed measles were neighborhood matched with three controls. We interviewed parents of case and control infants on potential risk factors for measles. Adjusted matched odds ratios (mOR) and 95% confidence intervals (CIs) were calculated by multivariable conditional logistic modeling. We calculated attributable fractions for risk factors that could be interpreted as causal.

Results:

Eight hundred thirty cases and 2303 controls were enrolled. In multivariable analysis, male sex (mOR 1.6 [1.3, 2.0]), age 5–7 months (mOR 3.9 [3.0, 5.1]), migration between counties (mOR 2.3 [1.6, 3.4]), outpatient hospital visits (mOR 9.4 [6.6, 13.3]) and inpatient hospitalization (mOR 107.1 [48.8, 235.1]) were significant risk factors. The calculated attributable fractions for hospital visits was 43.1% (95% CI: 40.1, 47.5%) adjusted for age, sex and migration.

Conclusions:

Hospital visitation was the largest risk factor for measles infection in infants. Improved hospital infection control practices would accelerate measles elimination in China.

Risk factors for measles in children aged 8 months-14 years in China after nationwide measles campaign: A multi-site case-control study, 2012-2013

INTRODUCTION

Endemic measles persists in China, despite >95% reported coverage of two measles-containing vaccine doses and nationwide campaign that vaccinated more than 100 million children in 2010. In 2011, almost half of the 9943 measles cases in China occurred in children eligible for measles vaccination. We conducted a case-control study during 2012-2013 to identify risk factors for measles infection in children aged 8 months-14 years.

METHODS

Children with laboratory-confirmed measles were age- and neighborhood-matched with three controls. We interviewed parents of case and control infants on potential risk factors for measles. We calculated adjusted matched odds ratios and 95% confidence intervals of risk factors. We calculated attributable fractions for risk factors that could be interpreted as causal and vaccine efficacy (VE) for the measles containing vaccine (MCV) used in the Chinese immunization program.

RESULTS

In all, 969 case-patients and 2845 controls were enrolled. In multivariable analysis, lack of measles vaccination both overall (mOR 22.7 [16.6, 31.1] and when stratified by region (east region, mOR 74.2 [27.3, 202]; central/western regions mOR 17.4 [12.5, 24.3]), hospital exposure (mOR 63.0, 95% CI [32.8, 121]), and migration among counties (overall mOR 3.0 [2.3, 3.9]) were significant risk factors. The calculated VE was 91.9-96.1% for a single dose of MCV and 96.6-99.5% for 2 doses.

CONCLUSIONS

Lack of vaccination was the leading risk factor for measles infection, especially in children born since the 2010 supplementary immunization activity. Reducing missed vaccination opportunities, improving immunization access for migrant children, and strengthening school/kindergarten vaccine checks are needed to strengthen the routine immunization program and maintain progress toward measles elimination in China.

Endemic and imported measles virus-associated outbreaks among adults, Beijing, China, 2013

In 2013, a resurgence of measles occurred in Beijing, China. The outbreaks occurred among adults and were associated with endemic genotype H1 and imported genotype D8 viruses. Migrant workers were disproportionately represented in the outbreaks; thus, vaccinating such workers against measles may be an effective strategy toward the elimination of this disease.

Economic evaluation of the routine childhood immunization program in the United States, 2009

OBJECTIVES

To evaluate the economic impact of the 2009 routine US childhood immunization schedule, including diphtheria and tetanus toxoids and acellular pertussis, Haemophilus influenzae type b conjugate, inactivated poliovirus, measles/mumps/rubella, hepatitis B, varicella, 7-valent pneumococcal conjugate, hepatitis A, and rotavirus vaccines; influenza vaccine was not included.

METHODS

Decision analysis was conducted using population-based vaccination coverage, published vaccine efficacies, historical data on disease incidence before vaccination, and disease incidence reported during 2005 to 2009. Costs were estimated using the direct cost and societal (direct and indirect costs) perspectives. Program costs included vaccine, administration, vaccine-associated adverse events, and parent travel and work time lost. All costs were inflated to 2009 dollars, and all costs and benefits in the future were discounted at a 3% annual rate. A hypothetical 2009 US birth cohort of 4,261,494 infants over their lifetime was followed up from birth through death. Net present value (net savings) and benefit-cost ratios of routine childhood immunization were calculated.

RESULTS

Analyses showed that routine childhood immunization among members of the 2009 US birth cohort will prevent ∼42,000 early deaths and 20 million cases of disease, with net savings of $13.5 billion in direct costs and $68.8 billion in total societal costs, respectively. The direct and societal benefit-cost ratios for routine childhood vaccination with these 9 vaccines were 3.0 and 10.1.

CONCLUSIONS

From both direct cost and societal perspectives, vaccinating children as recommended with these vaccines results in substantial cost savings.

Monitoring progress towards the elimination of measles in China: an analysis of measles surveillance data

OBJECTIVE

To analyse the epidemiology of measles in China and determine the progress made towards the national elimination of the disease.

METHODS

We analysed measles surveillance data - on the age, sex, residence and vaccination status of each case and the corresponding outcome, dates of onset and report and laboratory results - collected between January 2005 and October 2013.

FINDINGS

Between 2005 and October 2013, 596 391 measles cases and 368 measles-related deaths were reported in China. Annual incidence, in cases per 100 000 population, decreased from 9.95 in 2008 to 0.46 in 2012 but then rose to more than 1.96 in 2013. The number of provinces that reported an annual incidence of less than one case per million population increased from one in 2009 to 15 in 2012 but fell back to one in 2013. Median case age decreased from 83 months in 2005 to 14 months in 2012 and 11 months in January to October 2013. Between 2008 and 2012, the incidence of measles in all age groups, including those not targeted for vaccination, decreased by at least 93.6%. However, resurgence started in late 2012 and continued into 2013. Of the cases reported in January to October 2013, 40% were aged 8 months to 6 years.

CONCLUSION

Although there is evidence of progress towards the elimination of measles from China, resurgence in 2013 indicated that many children were still not being vaccinated on time. Routine immunization must be strengthened and the remaining immunity gaps need to be identified and filled.

Net financial gain or loss from vaccination in pediatric medical practices

OBJECTIVE

The goal was to determine the net return (gain or loss after costs were subtracted from revenues) to private pediatric medical practices from investing time and resources in vaccines and vaccination of their patients.

METHODS

A cross-sectional survey of a convenience sample of private medical practices requested data on all financial and capacity aspects of the practices, including operating expenses; labor composition and wages/salaries; private- and public-purchase vaccine orders and inventories; Medicaid and private insurance reimbursements; patient population; numbers of providers; and numbers, types, and lengths of visits. Costs were assigned to vaccination visits and subtracted from reimbursements from public- and private-pay sources to determine net financial gains/losses from vaccination.

RESULTS

Thirty-four practices responded to the survey. More than one half of the respondents broke even or suffered financial losses from vaccinating patients. With greater proportions of Medicaid-enrolled patients served, greater financial loss was noted. On average, private insurance vaccine administration reimbursements did not cover administration costs unless a child received > or = 3 doses of vaccine in 1 visit. Finally, wide ranges of per-dose prices paid and reimbursements received for vaccines indicated that some practices might be losing money in purchasing and delivering vaccines for private-pay patients if they pay high purchase prices but receive low reimbursements.

CONCLUSIONS

We conclude that the vaccination portion of the business model for primary care pediatric practices that serve private-pay patients results in little or no profit from vaccine delivery. When losses from vaccinating publicly insured children are included, most practices lose money.

Economic evaluation of the 7-vaccine routine childhood immunization schedule in the United States, 2001

OBJECTIVE

To evaluate the economic impact of the routine US childhood immunization schedule: diphtheria and tetanus toxoids and acellular pertussis; tetanus and diphtheria toxoids; Haemophilus influenzae type b conjugate; inactivated poliovirus; measles, mumps, and rubella; hepatitis B; and varicella vaccines.

DESIGN

Decision tree-based analysis was conducted using population-based vaccination coverage, published vaccine efficacies, historical data on disease incidence before vaccination, and disease incidence reported for 1995-2001. Costs were estimated using the direct cost and societal (direct and indirect costs) perspectives. Program costs included vaccine, administration, vaccine-associated adverse events, and parent travel and time lost. All costs were inflated to 2001 US dollars, and all costs and benefits in the future were discounted at a 3% annual rate.

PARTICIPANTS

A hypothetical 2001 US birth cohort of 3,803,295 infants was followed up from birth through death.

MAIN OUTCOME MEASURES

Net present value (net savings) and benefit-cost ratios of routine immunization.

RESULTS

Routine childhood immunization with the 7 vaccines was cost saving from the direct cost and societal perspectives, with net savings of 9.9 billion dollars and 43.3 billion dollars, respectively. Without routine vaccination, direct and societal costs of diphtheria, tetanus, pertussis, H influenzae type b, poliomyelitis, measles, mumps, rubella, congenital rubella syndrome, hepatitis B, and varicella would be 12.3 billion dollars and 46.6 billion dollars, respectively. Direct and societal costs for the vaccination program were an estimated 2.3 billion dollars and 2.8 billion dollars, respectively. Direct and societal benefit-cost ratios for routine childhood vaccination were 5.3 and 16.5, respectively.

CONCLUSION

Regardless of the perspective, the current routine childhood immunization schedule results in substantial cost savings.

Are Parental Vaccine Safety Concerns Associated With Receipt of Measles-Mumps-Rubella, Diphtheria and Tetanus Toxoids With Acellular Pertussis, or Hepatitis B Vaccines by Children?

OBJECTIVES

To identify parental perceptions regarding vaccine safety and assess their relationship with the immunization status of children.

DESIGN, SETTING, AND PARTICIPANTS

Case-control study based on a survey of a sample of households participating in the 2000-2001 National Immunization Survey, a quarterly random-digit-dialing sample of US children aged 19 to 35 months. Three groups of case children not up-to-date for 3 vaccines were compared with control children who were up-to-date for each respective vaccine. Main Outcome Measure Measles-containing or measles-mumps-rubella, diphtheria and tetanus toxoids and pertussis or diphtheria and tetanus toxoids with acellular pertussis, and hepatitis B vaccination coverage.

RESULTS

Among those sampled from the 2000-2001 National Immunization Survey, the household response rate was 2315 (52.1%) of 4440. Most respondents (>90%) in all groups believed vaccinations are important. In each case-control group, there was no significant difference between the percentage of case and control parents expressing general vaccine safety (range, 53.5%-64.1%). However, case parents were more likely to have asked that their child not be vaccinated for reasons other than illness (range, 10.2%-13.7% vs range, 2.9%-5.3%, respectively) and to believe their children received too many vaccinations (range, 3.4%-7.6% vs range, 0.8%-1.0%, respectively). Among the case-control group receiving a measles-containing or measles-mumps-rubella vaccination, only a small percentage of parents knew about the alleged association between autism and measles-mumps-rubella vaccinations (8.2%), and case parents were more likely to believe it than control parents (4.4% vs 1.5%, respectively; chi(2) P =.04).

CONCLUSIONS

Despite belief in the importance of immunization by a vast majority of parents, the majority of parents had concerns regarding vaccine safety. Strategies to address important misperceptions about vaccine safety as well as additional research assessing vaccine safety are needed to ensure public confidence.

Financing immunizations in the United States

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

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

BACKGROUND

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

OBJECTIVES

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

DESIGN AND SETTING

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

PARTICIPANTS

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

OUTCOME MEASURE

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

ANALYSIS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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