Relative vaccine effectiveness against Delta and Omicron COVID-19 after homologous inactivated vaccine boosting: a retrospective cohort study

ObjectiveTwo COVID-19 outbreaks occurred in Henan province in early 2022-one was a Delta variant outbreak and the other was an Omicron variant outbreak. COVID-19 vaccines used at the time of the outbreak were inactivated, 91.8%; protein subunit, 7.5%; and adenovirus5-vectored, 0.7% vaccines. The outbreaks provided an opportunity to evaluate variant-specific breakthrough infection rates and relative protective effectiveness of homologous inactivated COVID-19 vaccine booster doses against symptomatic infection and pneumonia.

DESIGN

Retrospective cohort study METHODS: We evaluated relative vaccine effectiveness (rVE) with a retrospective cohort study of close contacts of infected individuals using a time-dependent Cox regression model. Demographic and epidemiologic data were obtained from the local Centers for Disease Control and Prevention; clinical and laboratory data were obtained from COVID-19-designated hospitals. Vaccination histories were obtained from the national COVID-19 vaccination dataset. All data were linked by national identification number.

RESULTS

Among 784 SARS-CoV-2 infections, 379 (48.3%) were caused by Delta and 405 (51.7%) were caused by Omicron, with breakthrough rates of 9.9% and 17.8%, respectively. Breakthrough rates among boosted individuals were 8.1% and 4.9%. Compared with subjects who received primary vaccination series ≥180 days before infection, Cox regression modelling showed that homologous inactivated booster vaccination was statistically significantly associated with protection from symptomatic infection caused by Omicron (rVE 59%; 95% CI 13% to 80%) and pneumonia caused by Delta (rVE 62%; 95% CI 34% to 77%) and Omicron (rVE 87%; 95% CI 3% to 98%).

CONCLUSIONS

COVID-19 vaccination in China provided good protection against symptomatic COVID-19 and COVID-19 pneumonia caused by Delta and Omicron variants. Protection declined 6 months after primary series vaccination but was restored by homologous inactivated booster doses given 6 months after the primary series.

Real-world study of the effectiveness of BBIBP-CorV (Sinopharm) COVID-19 vaccine in the Kingdom of Morocco

Background

The Kingdom of Morocco approved BBIBP-CorV (Sinopharm) COVID-19 vaccine for emergency use on 22 January 2021 in a two-dose, three-to-four-week interval schedule. We conducted a retrospective cohort study to determine real-world BBIBP-CorV vaccine effectiveness (VE) against serious or critical hospitalization of individuals RT-PCR-positive for SARS-CoV-2 during the first five months of BBIBP-CorV use in Morocco.

Methods

The study was conducted among adults 18–99 years old who were tested by RT-PCR for SARS-CoV-2 infection between 1 February and 30 June 2021. RT-PCR results were individually linked with outcomes from the COVID-19 severe or critical hospitalization dataset and with vaccination histories from the national vaccination registration system. Individuals with partial vaccination (< 2 weeks after dose two) or in receipt of any other COVID-19 vaccine were excluded. Unadjusted and adjusted VE estimates against hospitalization for serious or critical illness were made by comparing two-dose vaccinated and unvaccinated individuals in logistic regression models, calculated as (1-odds ratio) * 100%.

Results

There were 348,190 individuals able to be matched across the three databases. Among these, 140,892 were fully vaccinated, 206,149 were unvaccinated, and 1,149 received homologous BBIBP-CorV booster doses. Unadjusted, full-series, unboosted BBIBP-CorV VE against hospitalization for serious or critical illness was 90.2% (95%CI: 87.8—92.0%). Full-series, unboosted VE, adjusted for age, sex, and calendar day of RT-PCR test, was 88.5% (95%CI: 85.8—90.7%). Calendar day- and sex-adjusted VE was 96.4% (95%CI: 94.6—97.6%) for individuals < 60 years, and was 53.3% (95%CI: 39.6—63.9%) for individuals 60 years and older. There were no serious or critical illnesses among BBIBP-CorV-boosted individuals.

Conclusions

Effectiveness of Sinopharm’s BBIBP-CorV was consistent with phase III clinical trial results. Two doses of BBIBP-CorV was highly protective against COVID-19-associated serious or critical hospitalization in working-age adults under real-world conditions and moderately effective in older adults. Booster dose vaccination was associated with complete protection, regardless of age, although only a small proportion of subjects received booster doses.

Prioritization of Vaccines for Inclusion into China’s Expanded Program on Immunization: Evidence from Experts’ Knowledge and Opinions

Background: Vaccine developers in China have made an increasing number of infectious diseases preventable through vaccination. An appropriate decision-making procedure is necessary for making wise decisions on whether to introduce new vaccines into the Expanded Program on Immunization (EPI). When there are several vaccines that could potentially be considered, a scientifically justifiable mechanism is needed for prioritizing and sequencing vaccines for consideration. Methods: We used a modified Delphi technique (MDT) to develop and refine an indicator system to prioritize vaccines and make policy recommendations concerning their introduction into China’s EPI system. From January through May 2021, thirty-nine experts were recruited and participated in a two-round Delphi survey that was based on a set of candidate indicators obtained through a literature review and reference to the WHO vaccine introduction recommendations. Using the resulting indicator system, we conducted a third consultation with a multi-disciplinary group of experts who scored five program-eligible candidate vaccines to determine prioritization and sequencing for consideration of inclusion into the EPI. Results: Response rates of the thirty-nine experts were 100% and 97.4% across the two rounds. Authority coefficients from rounds one to three were over 0.70, reflecting the high accuracy and reliability of the consultation. Coordination coefficients of importance scores for primary, secondary, and tertiary indicators were 0.486, 0.356, 0.275 in round one, and 0.405, 0.340, and 0.236 in round two. According to the scores from 30 experts using our indicator system, the sequence and scores (1–10 scale, 10 highest) of 5 candidate vaccines were varicella (6.91), meningococcal conjugate AC (6.83), Hib (6.74), influenza (6.56), and EV71 (6.17) vaccines. Conclusions: A modified Delphi technique effectively built a scientific, rational, comprehensive, and systematic indicator system for prioritizing vaccine candidates for consideration of inclusion into the EPI. The rank order will be used by the technical working groups of China’s National Immunization Advisory Committee to sequentially develop and present Evidence-to-Recommendation tables for making policy recommendations.

Effectiveness of adenovirus type 5 vectored and inactivated COVID-19 vaccines against symptomatic COVID-19, COVID-19 pneumonia, and severe COVID-19 caused by the B.1.617.2 (Delta) variant: evidence from an outbreak in Yunnan, China, 2021

Background

Methods

Findings

Interpretation

Vaccine events raising public concern and associated immunization program policy and practice changes, China, 2005-2021

INTRODUCTION

Several vaccine events causing public concern have occurred in China that were investigated and responded to by the central government. We describe causes, influences, and policy or practice changes associated with vaccine events that occurred between 2005 and 2021. We make recommendations to foster resilience in China's Expanded Program of Immunization (EPI) system and vaccination enterprises and to sustain vaccine and program confidence.

METHODS

Our study included all vaccine events since 2005 that were investigated and responded to by the central government of China. We verified mainstream and social media visibility of the events through Internet search. We extracted event times, causes, investigation processes, results, actions, and policy or practice regulation changes from official reports of government meetings and from official websites with media briefings.

RESULTS

Seven vaccine events were identified, each of which caused more than 100,000 mainstream or social media reports nationally or nationally and internationally. The events ranged in magnitude from 145 children receiving out-of-date oral poliovirus vaccine to a measles supplementary immunization activity involving 103 million children. Few, if any, children were directly harmed by vaccines in the events. Government responded to each event with program or policy changes, and in one case, with legislation. Responses affected the conduct of campaigns and supplementary immunization activities, use of schools as vaccination venues, financial incentives for vaccinating with non-program vaccines, vaccine procurement and distribution, and program policy making. The most fundamental response was enacting the country's first vaccine law, the 2019 Vaccine Administration Law, which guides virtually all aspects of vaccination work, from vaccine development through regulation, program implementation, and safety and impact monitoring.

CONCLUSIONS

All seven events generated substantial national and international mainstream and social media criticism and discussion, most commonly expressed through concerns of vaccine safety or vaccine effectiveness. Most had temporally associated temporary declines in vaccine confidence and coverage, jeopardizing decades of vaccination effort. The central government responded to each event by attempting to address root causes. Faithful implementation of the Vaccine Administration Law is fundamental to program strengthening and sustaining confidence of families, stakeholders, and government in vaccines and immunization in China.

Prediction of long-term kinetics of vaccine-elicited neutralizing antibody and time-varying vaccine-specific efficacy against the SARS-CoV-2 Delta variant by clinical endpoint

BACKGROUND

Evidence on vaccine-specific protection over time, in particular against the Delta variant, and protection afforded by a homologous third dose is urgently needed.

METHODS

We used a previously published model and neutralization data for five vaccines-mRNA-1273, BNT162b2, NVX-CoV2373, V01, and CoronaVac- to evaluate long-term neutralizing antibody dynamics and predict time-varying efficacy against the Delta variant by specific vaccine, age group, and clinical severity.

RESULTS

We found that homologous third-dose vaccination produces higher neutralization titers compared with titers observed following primary-series vaccination for all vaccines studied. We estimate the efficacy of mRNA-1273 and BNT162b2 against Delta variant infection to be 63.5% (95% CI: 51.4-67.3%) and 78.4% (95% CI: 72.2-83.5%), respectively, 14-30 days after the second dose, and that efficacy decreases to 36.0% (95% CI: 24.1-58.0%) and 38.5% (95% CI: 28.7-49.1%) 6-8 months later. Fourteen to 30 days after administration of homologous third doses, efficacy against the Delta variant would be 97.0% (95% CI: 96.4-98.5%) and 97.2% (95.7-98.1%). All five vaccines are predicted to provide good protection against severe illness from the Delta variant after both primary and homologous third dose vaccination.

CONCLUSIONS

Timely administration of third doses of SARS-CoV-2-prototype-based vaccines can provide protection against the Delta variant, with better performance from mRNA vaccines than from protein and inactivated vaccines. Irrespective of vaccine technology, a homologous third dose for all types of vaccines included in the study will effectively prevent symptomatic and severe COVID-19 caused by the Delta variant. Long-term monitoring and surveillance of antibody dynamics and vaccine protection, as well as further validation of neutralizing antibody levels or other markers that can serve as correlates of protection against SARS-CoV-2 and its variants, are needed to inform COVID-19 pandemic responses.

Vaccination strategy and challenges for consolidating successful containment of covid-19 with population immunity in China

Zijian Feng and colleagues argue that sustained elimination of SARS-CoV-2 in China offers flexibility in covid-19 vaccination policy and discuss the anticipated challenges and systematic monitoring necessary to keep the immunisation component of the response on track

Immunogenicity of two-dose and three-dose vaccination schedules with Sabin inactivated poliovirus vaccine in China: An open-label, randomized, controlled trial

BACKGROUND

We assessed immunogenicity of three-dose and two-dose immunization schedules with a Sabin-strain inactivated poliovirus vaccine (sIPV) produced by one Chinese vaccine manufacturer.

METHODS

This was an open label, randomized, controlled trial conducted in 16 vaccination clinics in Shandong province. Infants were allocated randomly to either a 3-dose study arm (sIPV administered at 2, 3, and 4 months of age) or a 2-dose arm (sIPV administered at 4 and 8-11 months of age). Poliovirus neutralizing antibodies were measured in sera collected prior to the first sIPV dose and one month after the last dose.

FINDINGS

We enrolled 560 infants; 536 (95.7%) completed the study. Final seropositivity rates were >98% for all three serotypes in both study arms. There were no statistically significant differences in seropositivity between the 2-dose and the 3-dose schedule. Final median reciprocal titres of polio antibodies were high overall (>1:768 for all serotypes) and statistically significantly higher in 2-dose recipients compared with 3-dose recipients (p < 0.001).

INTERPRETATION

This study offers evidence that two doses of sIPV administered at 4 and 8-11 months of age and three doses of sIPV administered at 2, 3, and 4 months of age both provide serological protection against poliomyelitis. Median reciprocal titres of polio antibodies were high overall, and were more related to the interval between doses than the number of doses, with the longer interval of the 2-dose schedule producing higher reciprocal titres than the shorter-interval 3-dose schedule. The protection provided by the 3-dose schedule is achieved earlier in life than the protection with the 2-dose schedule. Countries planning to use an IPV-only schedule in the post-eradication era can consider this 2-dose sIPV option as an immunogenic and dose-sparing strategy.

FUNDING

World Health Organization (from a grant from International PolioPlus Committee, Rotary International, Evanston, IL, USA).

Antibody seroprevalence in the epicenter Wuhan, Hubei, and six selected provinces after containment of the first epidemic wave of COVID-19 in China

BACKGROUND

China implemented containment measures to stop SARS-CoV-2 transmission in response to the COVID-19 epidemic. After the first epidemic wave, we conducted population-based serological surveys to determine extent of infection, risk factors for infection, and neutralization antibody levels to assess the real infections in the random sampled population.

METHODS

We used a multistage, stratified cluster random sampling strategy to conduct serological surveys in three areas - Wuhan, Hubei Province outside Wuhan, and six provinces selected on COVID-19 incidence and containment strategy. Participants were consenting individuals >1 year old who resided in the survey area >14 days during the epidemic. Provinces screened sera for SARS-CoV-2-specific IgM, IgG, and total antibody by two lateral flow immunoassays and one magnetic chemiluminescence enzyme immunoassay; positive samples were verified by micro-neutralization assay.

FINDINGS

We enrolled 34,857 participants (overall response rate, 92%); 427 were positive by micro-neutralization assay. Wuhan had the highest weighted seroprevalence (4•43%, 95% confidence interval [95%CI]=3•48%-5•62%), followed by Hubei-ex-Wuhan (0•44%, 95%CI=0•26%-0•76%), and the other provinces (<0•1%). Living in Wuhan (adjusted odds ratio aOR=13•70, 95%CI= 7•91-23•75), contact with COVID-19 patients (aOR=7•35, 95%CI=5•05-10•69), and age over 40 (aOR=1•36, 95%CI=1•07-1•72) were significantly associated with SARS-CoV-2 infection. Among seropositives, 101 (24%) reported symptoms and had higher geometric mean neutralizing antibody titers than among the 326 (76%) without symptoms (30±2•4 vs 15±2•1, p<0•001).

INTERPRETATION

The low overall extent of infection and steep gradient of seropositivity from Wuhan to the outer provinces provide evidence supporting the success of containment of the first wave of COVID-19 in China. SARS-CoV-2 infection was largely asymptomatic, emphasizing the importance of active case finding and physical distancing. Virtually the entire population of China remains susceptible to SARS-CoV-2; vaccination will be needed for long-term protection.

FUNDING

This study was supported by the Ministry of Science and Technology (2020YFC0846900) and the National Natural Science Foundation of China (82041026, 82041027, 82041028, 82041029, 82041030, 82041032, 82041033).

Caregiver and service provider vaccine confidence following the Changchun Changsheng vaccine incident in China: A cross-sectional mixed methods study

INTRODUCTION

The Changchun Changsheng Vaccine Incident (CCVI) occurred mid-2018 and involved irregularities in the manufacture and quality control of diphtheria-tetanus-acellular-pertussis and rabies vaccines. This study investigates vaccine confidence amongst Chinese caregivers and vaccination-service providers (VSPs) six months after the CCVI.

METHODS

Quantitative surveys were conducted in January 2019 with 2124 caregivers of children and 555 VSPs in three areas in China. The proportions of respondents who agreed to the four statements from the Vaccine Confidence Index™ were used to measure vaccine confidence. Descriptive and univariate analyses were performed to study the level of vaccine confidence. Semi-structured interviews were conducted with 48 caregivers, 43 VSPs and 9 immunization program managers. Interviews were analyzed thematically using a combination of deductive and inductive coding. Media surveillance was conducted to monitor public responses to the CCVI.

RESULTS

Media surveillance indicated that public attention to vaccine-related issues increased sharply immediately post-CCVI but declined rapidly thereafter. Six months post-CCVI, 96.0% of caregivers and the same proportion of VSPs reported that vaccination was important and compatible with their religious beliefs. 82.7% and 88.2% of caregivers agreed that vaccines were safe and effective. 92.8% and 94.6% of VSPs agreed that vaccines were safe and effective. Both caregivers and VSPs reported an immediate decline in vaccine confidence post-CCVI. In most cases this trust was regained over time following government and public health responses, however some people remained hesitant about vaccinating their children. Many VSPs were overwhelmed by consultations, workload and psychological pressure after the CCVI.

CONCLUSION

After an initial decline, vaccine confidence recovered to pre-incident levels six months after the CCVI. However, some caregivers moved from the higher to the lower end of the vaccine confidence spectrum, pointing to the need to promote the acceptance of vaccination especially given the need for new vaccines to control the coronavirus epidemic.

Active case finding with case management: the key to tackling the COVID-19 pandemic

COVID-19 was declared a pandemic by WHO on March 11, 2020, the first non-influenza pandemic, affecting more than 200 countries and areas, with more than 5·9 million cases by May 31, 2020. Countries have developed strategies to deal with the COVID-19 pandemic that fit their epidemiological situations, capacities, and values. We describe China's strategies for prevention and control of COVID-19 (containment and suppression) and their application, from the perspective of the COVID-19 experience to date in China. Although China has contained severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and nearly stopped indigenous transmission, a strong suppression effort must continue to prevent re-establishment of community transmission from importation-related cases. We believe that case finding and management, with identification and quarantine of close contacts, are vitally important containment measures and are essential in China's pathway forward. We describe the next steps planned in China that follow the containment effort. We believe that sharing countries' experiences will help the global community manage the COVID-19 pandemic by identifying what works in the struggle against SARS-CoV-2.

Two media-reported vaccine events in China from 2013 to 2016: Impact on confidence and vaccine utilization

BACKGROUND

China media reported infant deaths following hepatitis B vaccination in late 2013, leading to temporary suspension of hepatitis B vaccine (HepB Event) until the deaths were shown to be coincidental and the vaccine was of standard, good quality. In 2016, a criminal ring in Shandong province that had been purchasing, improperly storing, and reselling Category 2 vaccines (private-sector) to 60 (of 200,000) clinics for 5 years, was exposed, publicized, and prosecuted, and the potential health and epidemiological impacts were investigated to determine whether revaccination was necessary (Shandong Vaccine Event).

METHODS

We assessed parental confidence in vaccines through 9 telephone surveys in 6 and 11 provinces before, during, and after the two events. Provider confidence was assessed through in-person interviews following each event. Vaccine utilization was assessed using Immunization Information Management System data from township clinics.

RESULTS

In the early stages of each event, approximately 30% of parents indicated vaccine hesitancy and 18% said they would refuse routine immunization. Five and nine months after each event, hesitancy and refusal decreased, but not to pre-event levels. During the Shandong Vaccine Event, 49·1% of parents indicated refusal to use Category 2 vaccines; six months later, the rate was 32·8%. Use of HepB decreased by 21% during the first 2 weeks of the HepB Event and by 12·6% during the first 4 weeks of Shandong Vaccine Event, but returned to baseline in less than 3 months. Use of Category 2 vaccine decreased by 49·5% in the first 3 weeks of the Shandong Vaccine Event and by 28·7% 6 months later. After the Shandong Vaccine Event, 64% of clinicians held high confidence in routine immunization, lower than at baseline.

CONCLUSIONS

The two events caused mistrust, loss of confidence, and decreases in use of vaccines by parents and providers. In addition to ensuring immunization program integrity, effective communications and ongoing monitoring of vaccine use and confidence should be included to restore confidence and trust in vaccines.

Global landscape analysis of no-fault compensation programmes for vaccine injuries: A review and survey of implementing countries

To update the landscape analysis of vaccine injuries no-fault compensation programmes, we conducted a scoping review and a survey of World Health Organization Member States. We describe the characteristics of existing no-fault compensation systems during 2018 based on six common programme elements. No-fault compensation systems for vaccine injuries have been developed in a few high-income countries for more than 50 years. Twenty-five jurisdictions were identified with no-fault compensation programmes, of which two were recently implemented in a low- and a lower-middle-income country. The no-fault compensation programmes in most jurisdictions are implemented at the central or federal government level and are government funded. Eligibility criteria for vaccine injury compensation vary considerably across the evaluated programmes. Notably, most programmes cover injuries arising from vaccines that are registered in the country and are recommended by authorities for routine use in children, pregnant women, adults (e.g. influenza vaccines) and for special indications. A claim process is initiated once the injured party or their legal representative files for compensation with a special administrative body in most programmes. All no-fault compensation programmes reviewed require standard of proof showing a causal association between vaccination and injury. Once a final decision has been reached, claimants are compensated with either: lump-sums; amounts calculated based on medical care costs and expenses, loss of earnings or earning capacity; or monetary compensation calculated based on pain and suffering, emotional distress, permanent impairment or loss of function; or combination of those. In most jurisdictions, vaccine injury claimants have the right to seek damages either through civil litigation or from a compensation scheme but not both simultaneously. Data from this report provide an empirical basis on which global guidance for implementing such schemes could be developed.

Risk factors for measles virus infection and susceptibility in persons aged 15 years and older in China: 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 >100 million children in 2010. An increasing proportion of infections now occur among adults and there is concern that persistent susceptibility in adults is an obstacle to measles elimination in China. We performed a case-control study in six Chinese provinces between January 2012 to June 2013 to identify risk factors for measles virus infection and susceptibility among adults.

METHODS

Persons ≥15 years old with laboratory-confirmed measles were age and neighborhood matched with three controls. Controls had blood specimens collected to determine their measles IgG serostatus. We interviewed case-patients and controls about potential risk factors for measles virus infection and susceptibility. Unadjusted and adjusted matched odds ratios and 95% confidence intervals (CIs) were calculated via conditional logistic regression. We calculated attributable fractions for infection for risk factors that could be interpreted as causal.

RESULTS

899 cases and 2498 controls were enrolled. Among controls, 165 (6.6%) were seronegative for measles IgG indicating persistent susceptibility to infection. In multivariable analysis, hospital visit and travel outside the prefecture in the prior 1-3 weeks were significant risk factors for measles virus infection. Occupation and reluctance to accept measles vaccination were significant risk factors for measles susceptibility. The calculated attributable fraction of measles cases from hospital visitation was 28.6% (95% CI: 20.6-38.8%).

CONCLUSIONS

Exposure to a healthcare facility was the largest risk factor for measles virus infection in adults in China. Improved adherence to hospital infection control practices could reduce risk of ongoing measles virus transmission and increase the likelihood of achieving and sustaining measles elimination in China. The use of control groups stratified by serological status identified distinct risk factors for measles virus infection and susceptibility among adults.

Progress Toward Measles Elimination - China, January 2013-June 2019

What is already known about this topic?

China has historically had high measles incidence and many associated deaths. A comprehensive measles elimination plan during 2006-2012 substantially reduced measles incidence; however, a resurgence occurred during 2013-2015.

What is added by this report?

In China, measles surveillance, outbreak response, research, and program evaluation were used to strengthen routine immunization and target immunization activities for eliminating measles. Measles incidence declined from 31 per million in 2015 to 2.8 in 2018; only one measles-associated death has been reported during 2018-June 2019.

What are the implications for public health practice?

The World Health Organization-recommended strategy to eliminate measles can be effective, including in large, densely populated countries like China.

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.