Timeliness of childhood immunizations

Association of parent influenza vaccination and early childhood vaccinations using linked electronic health record data

INTRODUCTION

Parent and child vaccination behavior is related for human papillomavirus (HPV) and flu vaccine. Thus, it is likely that parental vaccination status is also associated with their children's adherence to guideline-concordant childhood vaccination schedules. We hypothesized that parent influenza (flu) vaccination would be associated with their child's vaccination status at age two.

METHODS

We used electronic health record data to identify children and linked parents seen in a community health center (CHC) within the OCHIN network (292 CHCs in 16 states). We randomly selected a child aged <2 years with ≥1 ambulatory visit between 2009-2018. Employing a retrospective, cohort study design, we used general estimating equations logistic regression to estimate the odds of a child being up-to-date on vaccinations based on their linked parents' flu vaccination status. We adjusted for relevant parent and child covariates and stratified by mother only, father only, and two-parent samples.

RESULTS

The study included 40,007 family-units: mother only = 35,444, father only = 2,784, and two parents = 1,779. A higher percentage of children were fully vaccinated if their parent or parents received a flu vaccine. Children in the two-parent sample whose parents both received a flu vaccine had more than twice the odds of being fully vaccinated, and two and a half times the odds of being fully vaccinated except flu vaccine compared to children with two parents who did not receive a flu vaccine (covariate-adjusted odds ratio [aOR] = 2.39, 95% CI = 1.67, 3.43 and aOR = 2.54, 95% CI = 1.54, 4.19, respectively).

CONCLUSIONS

Parent flu vaccination is associated with routine child vaccination. Future research is needed to understand if this relationship persists over time and in different settings.

Community health worker intervention improves early childhood vaccination rates: results from a propensity-score matching evaluation

BACKGROUND

Arizona's Health Start Program is a statewide community health worker (CHW) maternal and child health home visiting intervention. The objective of this study was to test if participation in Health Start during 2006-2016 improved early childhood vaccination completion rates.

METHODS

This retrospective study used 11 years of administrative, birth certificate, and immunization records. Propensity score matching was used to identify control groups, based on demographic, socioeconomic, and geographic characteristics. Results are reported by historically disadvantaged subgroups and/or with a history of low vaccine uptake, including Hispanic/Latinx and American Indian children, and children of low socioeconomic status and from rural areas, children with teen mothers and first-born children. The average treatment-on-the-treated (ATT) effect estimated the impact of Health Start on timely completion of seven early childhood vaccine series: diphtheria/tetanus toxoids and acellular/whole-cell pertussis (DTaP/DTP), Haemophilus influenzae type b (Hib), hepatitis B (Hep. B), measles-mumps-rubella (MMR), pneumococcal conjugate vaccine (PCV13), poliovirus, and varicella.

RESULTS

Vaccination completion rates (by age five) were 5.0% points higher for Health Start children as a group, and on average 5.0% points higher for several subgroups of mothers: women from rural border counties (ATT 5.8), Hispanic/Latinx women (ATT 4.8), American Indian women (ATT 4.8), women with less than high school education (ATT 5.0), teen mothers (ATT 6.1), and primipara women (ATT 4.5), compared to matched control groups (p-value ≤ 0.05). Time-to-event analyses show Health Start children complete vaccination sooner, with a hazard rate for full vaccination 13% higher than their matches.

CONCLUSION

A state-operated home visiting intervention with CHWs as the primary interventionist can effectively promote early childhood vaccine completion, which may reduce the incidence of preventable diseases and subsequently improve children's health. Effects of CHW interventions on vaccination uptake is particularly relevant given the rise in vaccine-preventable diseases in the US and globally.

TRIAL REGISTRATION

Approved by the University of Arizona Research Institutional Review Board (Protocol 1701128802), 25 January 2017.

Linking cohort data and Welsh routine health records to investigate children at risk of delayed primary vaccination

BACKGROUND

Delayed primary vaccination is one of the strongest predictors of subsequent incomplete immunisation. Identifying children at risk of such delay may enable targeting of interventions, thus decreasing vaccine-preventable illness.

OBJECTIVES

To explore socio-demographic factors associated with delayed receipt of the Diphtheria, Tetanus and Pertussis (DTP) vaccine.

METHODS

We included 1,782 children, born between 2000 and 2001, participating in the Millennium Cohort Study (MCS) and resident in Wales, whose parents gave consent for linkage to National Community Child Health Database records at the age seven years contact. We examined child, maternal, family and area characteristics associated with delayed receipt of the first dose of the DTP vaccine.

RESULTS

98.6% received the first dose of DTP. The majority, 79.6% (n = 1,429) received it on time (between 8 and 12 weeks of age), 14.2% (n = 251) received it early (prior to 8 weeks of age) and 4.8% (n = 79) were delayed (after 12 weeks of age); 1.4% (n = 23) never received it. Delayed primary vaccination was more likely among children with older natural siblings (risk ratio 3.82, 95% confidence interval (1.97, 7.38)), children admitted to special/intensive care (3.15, (1.65, 5.99)), those whose birth weight was > 4Kg (2.02, (1.09, 3.73)) and boys (1.53, (1.01, 2.31)). There was a reduced risk of delayed vaccination with increasing maternal age (0.73, (0.53, 1.00) per 5 year increase) and for babies born to graduate mothers (0.27, (0.08, 0.90)).

CONCLUSIONS

Although the majority of infants were vaccinated in a timely manner, identification of infants at increased risk of early or delayed vaccination will enable targeting of interventions to facilitate timely immunisation. This is to our knowledge the first study exploring individual level socio-demographic factors associated with delayed primary vaccination in the UK and demonstrates the benefits of linking cohort data to routinely-collected child health data.

Why Aren't We Achieving High Vaccination Rates for Rotavirus Vaccine in the United States?

BACKGROUND

Rotavirus vaccine (RV) coverage levels for US infants are <80%.

METHODS

We surveyed nationally representative networks of pediatricians by internet/mail from April to June, 2019. Multivariable regression assessed factors associated with difficulty administering the first RV dose (RV#1) by the maximum age.

RESULTS

Response rate was 68% (303/448). Ninety-nine percent of providers reported strongly recommending RV. The most common barriers to RV delivery overall (definite/somewhat of a barrier) were: parental concerns about vaccine safety overall (27%), parents wanting to defer (25%), parents not thinking RV was necessary (12%), and parent concerns about RV safety (6%). The most commonly reported reasons for nonreceipt of RV#1 by 4 to 5 months (often/always) were parental vaccine refusal (9%), hospitals not giving RV at discharge from nursery (7%), infants past the maximum age when discharged from neonatal intensive care unit/nursery (6%), and infant not seen before maximum age for well care visit (3%) or seen but no vaccine given (4%). Among respondents 4% strongly agreed and 25% somewhat agreed that they sometimes have difficulty giving RV#1 before the maximum age. Higher percentage of State Child Health Insurance Program/Medicaid-insured children in the practice and reporting that recommendations for timing of RV doses are too complicated were associated with reporting difficulty delivering the RV#1 by the maximum age.

CONCLUSIONS

US pediatricians identified multiple, actionable issues that may contribute to suboptimal RV immunization rates including lack of vaccination prior to leaving nurseries after prolonged stays, infants not being seen for well care visits by the maximum age, missed opportunities at visits and parents refusing/deferring.

Timeliness of routine childhood vaccinations in Indonesian infants in the first year of life

BACKGROUND

Vaccines have proven to be one of the most effective strategies to control infectious diseases and contributed to childhood survival. While high vaccine coverages provide individual's and herd immunity, age-appropriate vaccination or vaccine timeliness is important for maximum vaccine's protection, but often not evaluated. We aimed to describe the timeliness of childhood vaccination for Indonesian infants and identify risk factors associated with delayed vaccination.

METHODS

This study was a sub-study of the Indonesian Pneumonia and Vitamin D status (IPAD) study, a community-based cohort study to investigate pneumonia incidence in two districts in Yogyakarta province, Indonesia. Socio-demographic data were obtained from structured interviews and vaccine status was obtained from maternal and child health records. Timely vaccination was defined if the vaccine was received between four days or less before and within 28 days after the recommended age of vaccination.

RESULTS

359 (85%) out of 422 IPAD participants and their immunisation records were included. Between December 2015 and December 2017, vaccination coverage was high and ranged from 96.1% (Measles) to 100% (DTP-HepB-Hib 1). However, two thirds (67%, 242/359) of all participants had received either early or late vaccines, with dose 2 IPV (40%, 143/356), dose 3 IPV (56%, 196/349) and dose 3 DTP-HepB-Hib (29%, 103/354) most delayed, and only 1% received early doses. The main risk factors for untimely vaccination were if the infant was born in a private practice versus in a public health facility (AOR 1.90; 95% CI: 1.18-3.07) and rural residence (AOR 1.84; 95% CI: 1.15-2.94).

CONCLUSIONS

Despite high vaccine coverage for Indonesian infants (>95%), two thirds (67%) of infants had untimely vaccinations, with dose 3 IPV (56%) the most delayed. Future strategies should focus on coordination between government, health care providers, and carers to ensure timely access and vaccination of infants to ensure adherence to vaccination schedules.

Effect of a conditional cash transfer programme on infant up-to-date and timely vaccination

BACKGROUND

Conditional cash transfer (CCT) programmes are one of the strategies to increase vaccination coverage among underprivileged families by conditioning cash transfer to the up-to-date immunisation of children. However, there are gaps in knowledge of its impact on vaccination at the recommended age (timely).

METHODS

We performed two cross-sectional analyses of secondary data from a retrospective cohort, at the landmark ages of 12 and 24 months, to assess the effect of the Brazilian CCT on the up-to-date and timely vaccination in children born between 2014 and 2016 and resident in the city of Araraquara, São Paulo (Southeast Brazil). The Propensity Score Matching (PSM) was used to balance two pre-defined groups (beneficiaries and non-beneficiaries) according to the profile of socioeconomic and demographic characteristics.

RESULTS

From a total of 7386 children within the cohort, 22.2% (1636) were from beneficiary families of the CCT. After the pairing by PSM, the final sample size included in the analyses was 1440 for each group. We found higher up-to-date vaccination coverage, at 12 (92.1%, 95% CI=90.6% to 93.5%) and 24 months (83.8%, 95% CI=81.8% to 85.7%), among the CCT beneficiaries compared with the non-beneficiaries (85.1%, 95% CI=83.2% to 86.9% at 12 months and 73.6%, 95% CI=71.2% to 75.8% at 24 months). The coverage of timely vaccination did not statistically differ between beneficiaries (41.5%, 95% CI=38.9% to 44.1% and 17.4%, 95% CI=15.4% to 19.4%) and non-beneficiaries (40.7%, 95% CI=38.1% to 43.3% and 17.1%, 95% CI=15.2% to 19.1%) at 12 and 24 months, respectively.

CONCLUSION

The study highlights a positive effect of the CCT on vaccination coverage of the up-to-date infant vaccination schedule. However, there was no difference in timely vaccination.

Timeliness of Childhood Vaccination Coverage: the Growing Up in Singapore Towards Healthy Outcomes Study

Studies investigating timeliness for childhood vaccination are limited especially in Asia. We examined the timeliness of vaccine administration and associated factors among infant and young children in Singapore. A total of 782 children born between November 2009 and July 2011 from a prospective cohort in Singapore were studied. Vaccination records from birth to 24 months of age were obtained from the National Immunization Registry of Singapore. Multivariable logistic regression models were performed. By 2 years of age, 92.8% of children in our cohort experienced a delay in receiving 1 or more vaccine doses according to the recommended national immunization schedule. When vaccinations were reviewed by series for each vaccine, 15.6% received all vaccine series outside the recommended age ranges. Factors associated with receiving vaccination series outside the recommended ages included maternal aged ≤ 35 years (OR 2.00; 95% CI 1.09, 3.66), Malay (1.71; 1.01, 2.89) or Indian ethnicity (2.06; 1.19, 3.59), low monthly household income (1.91; 1.14, 3.18), having at least four children (3.46; 1.62, 7.38) and private (3.42; 1.80, 6.48) and multiple vaccination providers (3.91; 1.23, 12.48). These findings show an unacceptably high proportion of children experienced a delay in the receipt of their vaccinations. The identification of several demographic, socioeconomic, health-seeking behavioural and vaccine provider factors provides opportunities for targeted interventions to enhance the timeliness of childhood vaccination in Singapore.

Vaccination coverage of children with chronic diseases is inadequate especially for specifically recommended vaccines

AIM

Our objectives were to measure the vaccine coverage rates for children with chronic diseases as well as the prevalence of potentially harmful delays for generally recommended vaccines. We also identified the factors influencing non-adherence to vaccines specifically recommended for chronic conditions.

METHODS

Three non-interventional point-prevalence surveys were performed in 2014 in all paediatric units at Lille University Hospital among children aged 2 months-18 years with chronic diseases and vaccination data. Vaccine coverage and delays for generally recommended vaccines were studied. The children who were up-to-date and those under-vaccinated for specifically indicated vaccines were compared and the factors potentially associated with under-vaccination were studied with multivariable analysis.

RESULTS

We screened 682 patients: of 207 with chronic diseases, mainly neurological, muscular and respiratory disorders, 146 had vaccination data. Only 47% (95% confidence interval 39-55) were up-to-date for all generally recommended vaccinations; potentially harmful vaccination delays were high (26%-75%). Only 11% of the 81% of patients for whom some vaccines were specifically recommended were up-to-date. Low maternal education level was significantly associated with under-vaccination (adjusted odds ratio 10.5, 95% confidence interval 1.3-86.9, P = .03).

CONCLUSION

This study showed inadequate vaccine coverage rates and significant delays among children with chronic diseases.

A method for measuring the effect of certified electronic health record technology on childhood immunization status scores among Medicaid managed care network providers

OBJECTIVE

To provide a methodology for estimating the effect of U.S.-based Certified Electronic Health Records Technology (CEHRT) implemented by primary care physicians (PCPs) on a Healthcare Effectiveness Data and Information Set (HEDIS) measure for childhood immunization delivery.

MATERIALS AND METHODS

This study integrates multiple health care administrative data sources from 2010 through 2014, analyzed through an interrupted time series design and a hierarchical Bayesian model. We compared managed care physicians using CEHRT to propensity-score matched comparisons from network physicians who did not adopt CEHRT. Inclusion criteria for physicians using CEHRT included attesting to the Childhood Immunization Status clinical quality measure in addition to meeting "Meaningful Use" (MU) during calendar year 2013. We used a first-presence patient attribution approach to develop provider-specific immunization scores.

RESULTS

We evaluated 147 providers using CEHRT, with 147 propensity-score matched providers selected from a pool of 1253 PCPs practicing in Maryland. The estimate for change in odds of increasing immunization rates due to CEHRT was 1.2 (95% credible set, 0.88-1.73).

DISCUSSION

We created a method for estimating immunization quality scores using Bayesian modeling. Our approach required linking separate administrative data sets, constructing a propensity-score matched cohort, and using first-presence, claims-based childhood visit information for patient attribution. In the absence of integrated data sets and precise and accurate patient attribution, this is a reusable method for researchers and health system administrators to estimate the impact of health information technology on individual, provider-level, process-based, though outcomes-focused, quality measures.

CONCLUSION

This research has provided evidence for using Bayesian analysis of propensity-score matched provider populations to estimate the impact of CEHRT on outcomes-based quality measures such as childhood immunization delivery.

A Randomized Controlled Trial of Group Well-Child Care: Improved Attendance and Vaccination Timeliness

Well-child care has suboptimal outcomes regarding adherence to appointments and recall of guidance, especially among families facing structural barriers to health. Group well-child care (GWCC) aims to improve these outcomes by enhancing anticipatory guidance discussions and peer education. We conducted a randomized controlled trial, comparing GWCC with traditional, individual well-child care (IWCC) and assessed health care utilization, immunization timeliness, recall of anticipatory guidance, and family-centered care. Ninety-seven mother-infant dyads were randomized to GWCC or IWCC. Compared with IWCC infants, GWCC infants attended more of the 6 preventive health visits (5.41 vs 4.87, P < .05) and received more timely immunization at 6 months and 1 year but did not differ in emergency or hospital admission rates. There were no differences in mothers' reports of anticipatory guidance received or family-centered care. As primary care is redesigned for value-based care and structural vulnerabilities are considered, GWCC may be a key option to consider.

To Vaccinate or Not: The Relative Impact of Attitudes toward Autism Spectrum Disorders and the Ability to Interpret Scientific Information on Vaccination Decisions

Background. This pilot study investigated vaccine decision making, i.e., the relationships between knowledge and attitudes towards autism spectrum disorders (ASD), scientific literacy, attitudes toward the (MMR) vaccine, and children’s MMR vaccination status. Methods. A sample of 132 parents and expectant parents (mean age 38.40 years; >60% with university education) participated in a survey where they were asked about their knowledge of ASD, attitudes towards ASD and MMR, and their children’s MMR vaccine status. The participants also completed a standardized science test (The American College Test) to test their scientific literacy. Results. Knowledge of ASD was positively correlated with attitudes towards ASD. Attitudes towards ASD were positively correlated with scientific literacy and attitudes towards MMR. Attitudes towards MMR were positively correlated with MMR vaccine status (i.e., vaccination decision). Discussion. Factors other than scientific literacy seem to contribute towards children’s MMR vaccine status such as attitudes towards MMR. However, these are preliminary findings and need to be interpreted with caution.

Age-appropriate vaccination coverage and its determinants for the polio containing vaccine 1-3 and measles-containing vaccine doses in Zhejiang province, China: A community-based cross-sectional study

Background: This study aimed to evaluate the age-appropriate coverage and its associated risk factors for the primary vaccination of Polio containing vaccine (PCV) and measles-containing vaccine (MCV) through the secondary use of the 2018 Zhejiang provincial coverage survey among children aged 12-23 months. Methods: Data were collected through structured pre-tested Chinese version questionnaire by face-to-face interview among 770 mothers whose children aged 12-23 months. Age-appropriate vaccination coverage was measured using Chinese vaccination schedule recommendation. Bivariate and multivariate logistic regression models were adopted to identify determinants of the age-inappropriate vaccination. Results: The age-appropriate vaccination coverage of PCV1, PCV2, PCV3, and MCV was 88.8%, 80.8%, 73.6%, and 75.7%, respectively. The risk factors associated with the age-inappropriate vaccination of PCV 1-3 dose and MCV included child's gender, birthplace, living area, maternal education level, immigration status, monthly household income, participation of the pregnant women's seminar, antenatal care follow-up, knowledge on vaccination. Conclusion: The proportions of age-appropriate vaccination coverage were low compared with the up-to-date coverage. Modifiable factors were associated with age-inappropriate vaccinations. Vaccination interventions should consider identified modifiable factors to improve age-appropriate vaccination coverage.

Hepatitis B Birth Dose Effects on Childhood Immunization in the U.S

INTRODUCTION

The Advisory Committee on Immunization Practices recommends administering the first dose of hepatitis B vaccine at birth, making it the first vaccine that many children receive. However, few studies examine whether children who miss the birth dose are at increased risk of vaccination delay. This study investigates birth dose as a determinant of up-to-date immunization status at age 18 months, considering 7 core childhood vaccine series: diphtheria, tetanus, and acellular pertussis; polio; measles, mumps, and rubella; Haemophilus influenzae type B; varicella; hepatitis B; and pneumococcal conjugate vaccine.

METHODS

Cross-sectional data were collected in 2017 by National Immunization Survey-Child, a nationally representative survey of children aged 19-35 months living in the U.S., and were analyzed in 2019. The primary outcome was combined 7-vaccine series (4:3:1:3:3:1:4) up-to-date status at 18 months. Doubly robust estimates of association were calculated using survey logistic regression and propensity scores estimated with boosted classification and regression trees.

RESULTS

Children who received the birth dose had 2.01 (95% CI=1.74, 2.33) times the odds of being up-to-date on the combined 7-vaccine series as children who did not. ORs for all the 7 individual vaccine series were positive, ranging from 1.59 (95% CI=1.28, 1.97) for measles, mumps, and rubella to 4.97 (95% CI=3.97, 6.24) for hepatitis B.

CONCLUSIONS

Receiving the birth dose is positively associated with up-to-date status later in childhood, highlighting the importance of starting vaccination early. The association is insensitive to confounding by factors observed in National Immunization Survey-Child, but investigation of unobserved factors such as vaccine hesitancy could provide critical information to guide intervention strategy.

Infectious Diseases among Refugee Children

In recent years, there has been a substantial increase in refugee and asylum-seeking adults, adolescents and children to high-income countries. Infectious diseases remain the most frequently identified medical diagnosis among U.S.-bound refugee children. Medical screening and immunization are key strategies to reduce the risk of infectious diseases in refugee, internationally adopted, and immigrant children. Notable infectious diseases affecting refugee and other newly arriving migrants include latent or active tuberculosis, human immunodeficiency virus type 1 (HIV), hepatitis B, hepatitis C, vaccine-preventable diseases, malaria, and other parasitic infections. The U.S. Centers for Disease Control and Prevention and the American Academy of Pediatrics have published guidelines for health assessment of newly arriving immigrant, refugee, and internationally adopted children. Although, data on the health risks and needs of refugee exists in some high-income countries, there is an urgent need to develop robust evidence-informed guidance on screening for infectious diseases and vaccination strategies on a broader scale to inform national policies. Innovative approaches to reach migrant communities in the host nations, address health and other complex barriers to improve access to high-quality integrated health services, and strong advocacy to mobilize resources to improve health, safety, and wellbeing for refugee children and their families are urgent priorities.

Age-appropriate vaccination coverage and its associated factors for pentavalent 1-3 and measles vaccine doses, in northeast Ethiopia: A community-based cross-sectional study

BACKGROUND

In Ethiopia, there are limited studies on age-appropriate vaccinations that children received at the recommended specific ages. Therefore, we assessed age-appropriate vaccinations coverage and its associated factors among children 12 to 23 months of age in Menz Lalo district, northeast Ethiopia.

METHODS

A community-based cross-sectional study was conducted in Menz Lalo district from March to April/2018 among 417 mothers/caregivers with children 12 to 23 months of age using simple random sampling technique. Data were collected using a pretested structured questionnaire. Information about children's vaccination status was collected from vaccination cards. Age-appropriate vaccination coverage was measured using World Health Organization vaccination schedule recommendation. Data was entered into Epi-Info7 software and exported to SPSS-20 for analysis. Four consecutive logistic regression models were performed to identify factors associated with age-inappropriate vaccinations. A P-value of ≤ 0.05 was considered to state statistically significant associations.

RESULTS

Age-appropriate vaccination coverage was 39.1% (95% CI: 34.3 to 44) for pentavalent 1, 36.3% (95% CI: 31.6 to 41.5) for pentavalent 2, 30.3% (95% CI: 25.6 to 35) for pentavalent 3 and 26.4% (95% CI: 21.7 to 31) for measles vaccine doses. Age-inappropriate pentavalent 1-3 vaccinations was associated with being male sex (AOR: 0.47, 95% CI: 0.29-0.74), lack of telephone (AOR: 2.2, 95% CI: 1.4-3.6), lack of usual caretaker (AOR: 2.6, 95% CI: 1.3-5.2), unplanned pregnancy (AOR: 1.9, 95% CI: 1.1-3.5), missing pregnant women's conference (AOR: 2.7, 95% CI: 1.3-5.7), decreasing birth order (AOR: 0.34, 95% CI: 0.17-0.68) and insufficient knowledge (AOR: 2.7, 95% CI: 1.6-4.4).

CONCLUSION

The proportions of age-appropriate vaccination coverage were low in the study area. Modifiable factors were associated with age-inappropriate vaccinations. Vaccination interventions should consider identified modifiable factors to improve age-appropriate vaccinations coverage.

Pediatric Hospitalizations: Are We Missing an Opportunity to Immunize?

OBJECTIVES

Fewer than half of children receive all recommended immunizations on time. Hospitalizations may be opportunities to address delayed immunizations. Our objectives were to assess (1) prevalence of delayed immunizations among hospitalized patients, (2) missed opportunities to administer delayed immunizations, and (3) time to catch up after discharge.

METHODS

We conducted a retrospective cohort study investigating immunization status of patients 0 to 21 years of age admitted to an academic children's center from 2012 to 2013 at the time of admission, at discharge, and 18 months postdischarge. Immunization catch-up at 18 months postdischarge was defined as having received immunizations due on discharge per Centers for Disease Control and Prevention recommendations. χ² and t test analyses compared characteristics among patients caught up and not caught up at 18 months postdischarge. Analysis of variance and logistic regression analyses compared mean number of immunizations needed and odds of immunization catch-up among age groups. Kaplan-Meier and Cox proportional hazards analyses compared catch-up time by age, race, sex, and insurance.

RESULTS

Among 166 hospitalized patients, 80 were not up to date on immunizations at admission, and only 1 received catch-up immunizations before discharge. Ninety-nine percent (79 of 80) were not up to date on discharge per Centers for Disease Control and Prevention recommendations. Thirty percent (24 of 79), mostly adolescents, were not caught up at 18 months postdischarge. Median postdischarge catch-up time was 3.5 months (range: 0.03-18.0 months). Patients 0 to 35 months of age were more likely to catch up compared with those of other ages (hazard ratio = 2.73; P = .001), with no differences seen when comparing race, sex, or insurance.

CONCLUSIONS

Pediatric hospitalizations provide important opportunities to screen and immunize children.

Acellular Pertussis Vaccine Effectiveness Over Time

OBJECTIVES

To determine pertussis risk by diphtheria-tetanus-acellular pertussis (DTaP) vaccination status and time since last DTaP dose.

METHODS

Children born at Kaiser Permanente Northern California between 1999 and 2016 were followed from 3 months of age until they tested positive for pertussis; disenrolled from Kaiser Permanente Northern California; received the tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis, adsorbed vaccine; turned 11 years of age, or the end of the study period. DTaP vaccination status was categorized on the basis of the number of doses received in relation to the number of doses expected according to the Advisory Committee on Immunization Practice-recommended ages.

RESULTS

Among 469 982 children ages 3 months to 11 years, we identified 738 pertussis cases. A total of 99 cases were unvaccinated, 36 were undervaccinated, 515 were fully vaccinated, and 88 were fully vaccinated plus 1 dose. Pertussis risk was 13 times higher among unvaccinated (adjusted hazard ratio [aHR] = 13.53; 95% confidence interval [CI] 10.64-17.21) compared with fully vaccinated children and 1.9 times higher (aHR = 1.86; 95% CI 1.32-2.63) among undervaccinated children. Among vaccinated children ages 19 to <84 months, pertussis risk was 5 times higher (aHR = 5.04; 95% CI 1.84-13.80) ≥3 years vs <1 year after vaccination. Among children ages 84 to 132 months, risk was 2 times higher (aHR = 2.32; 95% CI 0.97-5.59) ≥6 years vs <3 years after vaccination.

CONCLUSIONS

Undervaccinated and especially unvaccinated children were at greater risk of pertussis. However, most pertussis cases occurred among children age-appropriately vaccinated who were further away from their last DTaP dose, suggesting that suboptimal vaccine effectiveness played a major role in recent pertussis epidemics.

Age appropriateness of vaccination with recommended childhood vaccines in Sri Lanka

Vaccination status is conventionally measured by up-to-date coverage. This method does not take in to account whether the vaccines were received at the correct age and interval which is essential for optimal disease protection. Sri Lanka – a lower middle-income country in the Indian Ocean, has previously presented with high vaccination coverage for all childhood vaccines. However, few studies investigating timeliness of vaccinations have until now been carried out in Sri Lanka.

Aim: This study was carried out to investigate the individual coverage and age appropriateness of vaccination, in two different demographic settings in Anuradhapura district, Sri Lanka. The study of cross-sectional descriptive design included 633 children born in 2011. Public Health Midwives kept hand-written documentation of the birth and vaccination dates on each child in her geographic area. Vaccination ages were then compared to the timelines of vaccination provided by the Epidemiology Unit of Sri Lanka.

The vaccination coverage for all antigens was 97.5% (94.2–99.7%) at age 5–6 years. Timeliness of doses was between 65.0 and 88.6 % (median 80.7%; 65.0–88.6) and significantly lower in the urban population compared to the rural. The present study shows that the vaccine coverage in both urban and rural areas in Sri Lanka was high and that the timeliness predominantly followed national recommendations.

Completeness and timeliness of diphtheria-tetanus-pertussis, measles-mumps-rubella, and polio vaccines in young children with chronic health conditions: A systematic review

OBJECTIVE

To systematically review literature on uptake and timeliness of diphtheria-tetanus-pertussis, measles-mumps-rubella, and/or polio-containing vaccines ininfants who were born preterm, with a low birth weight, and/or with chronic health conditions that were diagnosed within the first 6 months of life.

METHODS

Using a standardized search strategy developed by a medical librarian, records were extracted from MEDLINE, Embase, Database of Abstracts of Reviews of Effects, and CINAHL up to May 8, 2018.

RESULTS

Out of the 1997 records that were screened, we identified 21 studies that met inclusion criteria. Eleven studies assessed vaccine coverage and/or timeliness in preterm infants, 6 in low birth weight infants, and 7 in children with chronic health conditions. Estimates of coverage in these populations were highly variable, ranging from 40% to 100% across the vaccines and population groups.

CONCLUSIONS

There is a lack of studies reporting coverage and timeliness of routine immunizations in special populations of children.

POLICY IMPLICATIONS

Our review suggests a need for improved surveillance of immunization status in special populations of infants, as wellas aneed for standardization of reporting practices.

Determinants of Timely Presentation for Birth Dose Vaccination at an Immunization Centre in North-central Nigeria

Background:

Timely receipt of immunization is an essential prerequisite to ensure early protection of the child. However, a low proportion of children in Nigeria benefit from the timely administration of the birth dose vaccines.

Objectives:

These were identification of factors associated with timely presentation and reasons for presentation beyond 24 hours at an immunization centre in Ilorin, Nigeria.

Method:

A descriptive cross-sectional study involving 480 mother-infant pairs was conducted at an immunization centre. Socio-demographic, antenatal care (ANC) and delivery details, infant’s birthday and day of presentation for vaccination were recorded. Logistic regression was used to identify factors associated with time to presentation within day one.

Findings:

239 (49.8%), 421 (87.7%) and 454 (94.6%) babies were vaccinated within days one, seven and 14 respectively. Post-secondary education level of mothers (OR = 3.60; 95% C.I: 1.30–9.91), antenatal care attendance (OR = 9.55; 95% C.I: 1.75–52.12), and hospital delivery (OR = 6.36; 95% C.I: 1.33–30.38) were associated with presentation within day one. Having correct knowledge of the immunization schedule increased the odds of early presentation by three times, p = 0.025. The commonest reason for presentation after day one for vaccination was weekend/public holiday delivery identified in 83 (35.2%) mother-infant pairs.

Conclusion:

Hospital delivery, attendance at antenatal care, postsecondary education and knowledge of the immunization schedule were factors associated with timely presentation for birth dose vaccination. Strategies to improve timeliness of the birth dose vaccination should target babies delivered outside the hospital as well as during weekends in the hospital. Also, inclusion of immunization into the health education curriculum of schools could be beneficial.

Maternal Education Is Inversely Related to Vaccination Delay among Infants and Toddlers

OBJECTIVE

To determine the association between parents' level of education and delay in vaccination among infants and toddlers.

STUDY DESIGN

A case-control study done in 2015-2016. Charts of 2- to 4-year-old children vaccinated in 5 neighborhood Maternal-Child Health Centers (MCHCs) in southern Israel were examined for demographic variables. Five vaccination opportunities between age 7 months and 18 months were selected to test for delays. In each MCHC, children vaccinated at the longest time-period after planned vaccination dose (fifth quintile) were compared with those vaccinated during the middle quintile. Using this relative delay approach rather than absolute delay approach permitted us to adjust the findings to the prevailing environmental and to cultural and programmatic variations between the various neighborhoods. Each of the planned vaccination visits and overall, demographic and health behavior-related variables that were significantly associated to delays by univariate analysis were tested by multivariate analysis and further adjusted by using stepwise logistic regression, using goodness of fit measures.

RESULTS

Data for 2072 subjects were collected (398-426 per MCHC). Fathers' education was not associated with delays. In contrast, mothers' education was inversely associated with the probability of vaccination delay by 4%-9% (depending on the vaccination visit) for each year of schooling beyond 10 years.

CONCLUSION

Using the relative delay approach, we demonstrated that maternal education, measured by schooling years, was independently inversely associated with risk of vaccination delay. This suggests that education can be regarded as an important positive component of the overall disease prevention planning at national and global levels.

Inequalities in childhood vaccination timing and completion in London

The UK primary vaccination course includes vaccination against diphtheria, tetanus, pertussis, polio and Haemophilus influenzae type b (DTaP/IPV/Hib) and is scheduled at ages four, 8 and 12 weeks, followed by a 'preschool booster' at age three years four months. Vaccine coverage is generally measured at age one, two and five years. In addition to high coverage, vaccination should be timely to maximise population protection. Vaccination histories for 315,381 children born March 2001 to April 2010 were extracted from Child Health Information Systems in nine London health service areas and grouped into first and fifth birthday cohorts. We assessed timeliness of receipt of DTaP/IPV/Hib and drop-out rates by ethnicity, deprivation and area. Most children received their first, second and third doses on time at two, three, and four months. Among children completing by one year and after adjusting for deprivation and health area, compared with White-British children, Somali and Bangladeshi children were less likely to have received three doses of DTaP/IPV/Hib by six months of age (-11% and -5% respectively). Differences in timeliness by deprivation and health area existed, but were smaller. Compared with White-British children, children of Polish, Somali and Caribbean ethnicities were less likely to return for preschool booster, with a drop-out rate at least 7% higher in these groups. Within the fifth birthday cohort, only 2.3% of children who were completely unvaccinated (575/25,095) at age one year were fully vaccinated by age five. Higher proportions of partially vaccinated (one or two doses) children at age one year went on to be fully vaccinated by age five ((836/3213) 26.0% and (3565/6076) 58.7% respectively). These inequalities suggest that tailored approaches may be required to target specific groups with regards to improving vaccine uptake.

[Assessment of vaccination coverage of children in a medium-sized Brazilian city using electronic immunization registry]

Administrative data show high vaccination coverage rates in Brazil, but there is no assessment of the validity and timeliness of dose administration, or whether the vaccination schedule is complete. This study assessed timely and updated coverage rates in children 12 to 24 months of age. This was a longitudinal population-based study in Araraquara, São Paulo State, a predominantly urban medium-sized municipality, using the Juarez System, an electronic immunization registry (EIR). Coverage rates were assessed in 49,741 children born from 1998 to 2013, a period in which five different vaccination schedules were used. Trends were estimated with the Prais-Winsten linear regression method. Updated coverage of the complete schedule varied from 79.5% to 91.3% at 12 months and from 75.8% to 86.9%, at 24 months. Timely coverage (all doses applied at the recommended ages, with no delays) ranged from 53.3% to 74% at 12 months and from 36.7% to 53.8% at 24 months. There was an upward trend in updated coverage at 24 months. The delays in relation to recommended age increased starting at six months and appeared to relate more to age than to the number of doses in the schedule. The proportion of invalid and late doses was lower than in other studies. Despite the increase in the number of doses in the vaccination schedule, the study showed high updated coverage rates and higher timely coverage than reported in the national and international literature; however, more effort is needed to increase timeliness. EIR proved relevant for assessing and monitoring vaccination coverage with more accurate analyses.

Vaccination Patterns in Children After Autism Spectrum Disorder Diagnosis and in Their Younger Siblings

IMPORTANCE

In recent years, rates of vaccination have been declining. Whether this phenomenon disproportionately affects children with autism spectrum disorder (ASD) or their younger siblings is unknown.

OBJECTIVES

To investigate if children after receiving an ASD diagnosis obtain their remaining scheduled vaccines according to the Advisory Committee on Immunization Practices (ACIP) recommendations and to compare the vaccination patterns of younger siblings of children with ASD with the vaccination patterns of younger siblings of children without ASD.

DESIGN, SETTING, AND PARTICIPANTS

This investigation was a retrospective matched cohort study. The setting was 6 integrated health care delivery systems across the United States within the Vaccine Safety Datalink. Participants were children born between January 1, 1995, and September 30, 2010, and their younger siblings born between January 1, 1997, and September 30, 2014. The end of follow-up was September 30, 2015.

EXPOSURES

Recommended childhood vaccines between ages 1 month and 12 years.

MAIN OUTCOME AND MEASURE

The proportion of children who received all of their vaccine doses according to ACIP recommendations.

RESULTS

The study included 3729 children with ASD (676 [18.1%] female), 592 907 children without ASD, and their respective younger siblings. Among children without ASD, 250 193 (42.2%) were female. For vaccines recommended between ages 4 and 6 years, children with ASD were significantly less likely to be fully vaccinated compared with children without ASD (adjusted rate ratio, 0.87; 95% CI, 0.85-0.88). Within each age category, vaccination rates were significantly lower among younger siblings of children with ASD compared with younger siblings of children without ASD. The adjusted rate ratios varied from 0.86 for siblings younger than 1 year to 0.96 for those 11 to 12 years old. Parents who had a child with ASD were more likely to refuse at least 1 recommended vaccine for that child's younger sibling and to limit the number of vaccines administered during the younger sibling's first year of life.

CONCLUSIONS AND RELEVANCE

Children with ASD and their younger siblings were undervaccinated compared with the general population. The results of this study suggest that children with ASD and their younger siblings are at increased risk of vaccine-preventable diseases.

Vaccination Timeliness at Age 24 Months in Michigan Children Born 2006-2010

INTRODUCTION

Delays in vaccination can stymie the development of herd immunity, and a large proportion of children in the U.S. are known not to receive vaccines on time. This study quantifies delays in vaccination, compares vaccination timeliness to the proportion of children vaccinated, and evaluates the impact of combination vaccine use and timely administration of hepatitis B vaccine birth dose on vaccine timeliness among Michigan children.

METHODS

This retrospective cohort study used data from the Michigan Care Improvement Registry-the state immunization information system-for children born 2006-2010. Children aged 24 months as of December 31, 2012, were included. The proportion of children with timely administration of vaccine doses was calculated, and the mean days of vaccination delay with SD were reported.

RESULTS

Among 620,592 Michigan children, 42.2% had received all vaccines, but only 13.2% were vaccinated on time by age 24 months. Children's vaccinations were delayed an average of 59.2 (SD=91.2) days by age 24 months for all recommended vaccine doses. Children who received a timely hepatitis B vaccine birth dose or who received a combination vaccine had less delay in vaccination.

CONCLUSIONS

Michigan children have high vaccination coverage based on standard measures but few receive these vaccines on time. Promoting use of combination vaccines may improve parental compliance with timely vaccination of children.

Timeliness of vaccination in infants followed by primary-care pediatricians in France

Vaccination status is more often evaluated by up-to-date vaccination coverage rather than timeliness of immunization. Delaying vaccination may be dangerous during infancy. The aim of this study was to identify the importance of potentially dangerous vaccination delay (previously defined) and determinants of these delays. We conducted a national, prospective, vaccination survey in June 2014, with primary care pediatricians. Children, 2 to 24 months of age, were included. Data about vaccination were extracted from their health books. Additional data were collected through a standardized questionnaire. Vaccine coverage rate and timeliness were calculated. Variables associated with a potentially dangerous vaccination delay as previously defined were determined by a multivariable analysis. Among the 443 included children (mean age 10.8 months, 49% males), 13% to 58% of vaccine doses according to vaccine type were done with a potentially dangerous delay. Globally, 47% of children had at least one potentially dangerous immunization delay. We identified two risk factors of potentially dangerous delayed immunization globally: an increasing age of the child (adjusted odds ratio: 1.2, 95% confidence interval [CI]: 1.1-1.3, p < 10^-3), and a working mother (adjusted OR: 2.4, 95% CI: 1.2-4.7, p = 0.01). Despite a good vaccine coverage rate, a large number of children had a potentially dangerous vaccination delay. A high level of vigilance regarding these immunization delays, and particularly to the patients sharing the risk factors of immunization delay identified here, can increase quality and effectiveness of the vaccine protection.

Does birth under-registration reduce childhood immunization? Evidence from the Dominican Republic

The consequences of lacking birth certificates remain largely unexplored in the economic literature. We intend to fill this knowledge gap studying the effect of lacking birth certificates on immunization of children in the Dominican Republic. This is an interesting country because a significant number of children of Haitian descent face the consequences of lacking proper documentation. We use the distance to the civil registry office and the mother's document of identification as instrumental variables of the child's birth certificate. After controlling for distance to immunization services and other determinants, this paper finds that children between 0 and 59 months of age that do not have birth certificates are behind by nearly one vaccine (out of a total of nine) compared to those that have birth certificates.

Measuring the timeliness of childhood vaccinations: Using cohort data and routine health records to evaluate quality of immunisation services

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Most children received the first dose of primary vaccines on time.

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Timeliness of vaccination decreased with vaccine dose.

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Most children had appropriate intervals between doses; marked variation occurred.

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The quality of routine vaccination records in Wales is high.

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Parental report of MMR status is reliable.

Background

To achieve full benefits of vaccination programmes, high uptake and timely receipt of vaccinations are required.

Objectives

To examine uptake and timeliness of infant and pre-school booster vaccines using cohort study data linked to health records.

Methods

We included 1782 children, born between 2000 and 2001, participating in the Millennium Cohort Study and resident in Wales, whose parents gave consent for linkage to National Community Child Health Database records at the age seven year contact. We examined age at receipt, timeliness of vaccination (early, on-time, delayed, or never), and intervals between vaccine doses, based on the recommended schedule for children at that time, of the following vaccines: primary (diphtheria, tetanus, pertussis (DTP), polio, Meningococcal C (Men C), Haemophilus influenzae type b (Hib)); first dose of measles, mumps and rubella (MMR); and pre-school childhood vaccinations (DTP, polio, MMR). We compared parental report with child health recorded MMR vaccination status at age three years.

Results

While 94% of children received the first dose of primary vaccines early or on time, this was lower for subsequent doses (82%, 65% and 88% for second and third doses and pre-school booster respectively). Median intervals between doses exceeded the recommended schedule for all but the first dose with marked variation between children. There was high concordance (97%) between parental reported and child health recorded MMR status.

Conclusions

Routine immunisation records provide useful information on timely receipt of vaccines and can be used to assess the quality of childhood vaccination programmes. Parental report of MMR vaccine status is reliable.

Reply to Editorial on "What is a potentially damaging vaccination delay in children younger than 2 years?"

Vaccine guidelines should be followed at the best to avoid vaccine preventable diseases in children and particularly in at-risk children. The authors of the editorial rightly emphasize the risk of hepatitis B in unimmunized children. Vaccine delays are frequent and indicators of vaccine delays are needed. Thresholds that identify an important increase in relative risks are the most relevant, for hepatitis B as well.

Effect of combination vaccines on completion and compliance of childhood vaccinations in the United States

Vaccination at age-appropriate intervals increases protection against morbidity and mortality; however, compliance rates among children remain low partly due to a complicated vaccination schedule. Use of combination vaccines reduces the number of injections per visit; however, there is limited evidence quantifying the effect of combination vaccines on vaccination rates. To examine how combination vaccines impact childhood completion (receipt of recommended doses) and compliance (receipt of age-appropriate vaccinations) rates, this study analyzed vaccination data from the 2012 National Immunization Survey (NIS), a nationally representative cross-sectional survey of caregivers of children aged 24 to 35 months in the United States. Vaccines were categorized as combination or single antigen. Vaccine completion was measured at ages 8, 18, and 24 months. Vaccine compliance and time undervaccinated were measured at 24 months. Children who received at least 1 combination vaccine (86%) had a higher completion rate (69%) and compliance with the full vaccine series (4:3:1:3:3:1:4 series) at 24 months (24%) than those who received only single-antigen vaccines (50% and 13%, respectively). Receipt of combination vaccine was associated with an increased likelihood of completing all recommended vaccinations at 24 months (odds ratio [OR] = 2.5; P < 0.001), receiving all vaccinations at age-appropriate times (OR = 2.2; P < 0.001), and less than 7 months undervaccinated (OR = 2.4; P < 0.001). Combination vaccines were associated with improved completion and compliance and should be encouraged among children who are undervaccinated or who received single-antigen vaccines only.

Determinants of under-immunization and cumulative time spent under-immunized in a Quebec cohort

BACKGROUND

Under-immunization refers to a state of sub-optimal protection against vaccine preventable diseases. Vaccine coverage for age may not capture intentional or non-intentional spacing of vaccines in the recommended provincial immunization guidelines. We aimed to identify factors associated with coverage and under-immunization and to determine the number of days during which children were under-immunized during their first 24months of life.

METHODS

Secondary analysis of children ≤3years recruited through active surveillance for gastroenteritis from three Quebec pediatric emergency departments from 2012 to 2014. Vaccination status for children at least 24months of age was determined using provincial immunization guidelines. Cumulative days under-immunized were calculated for DTaP-VPI-Hib, PCV, MMR, and Men-C-C. Factors associated with up-to-date (UTD) status at 24months of life and for under-immunization ≥6months were analyzed using logistic regression.

RESULTS

Of 246 eligible children, 180 (73%) were UTD by 24months of life. The mean cumulative days under-immunized for MMR was 107days, for PCV 209days, for Men-C-C 145days, and for DTaP-VPI-Hib 227days. Overall, 149 children (60%) experienced delay for at least 1 vaccine. Factors associated with both an UTD status at 24months and concurrently associated with being under-immunization ≥6months, included timely initiation of immunization (OR=5.85; 95% CI: 2.80-12.22) and (OR=0.13; 95% CI: 0.07-0.24), failure to co-administer 18-month vaccines (OR=0.15; 95% CI: 0.10-0.21) and (OR=3.29; 95% CI: 2.47-4.39), and having a household with ≥3 children under 18years ((OR=0.50; 0.28-0.86) and (OR=2.99; 1.45-6.22), respectively.

CONCLUSION

Paired with an unexpected low level of coverage at 24months of life, the majority of our cohort also experienced a state of under-immunization for a least one vaccine. Estimates of coverage do not capture intentional or non-intentional gaps in protection from vaccine preventable illnesses. Timely preventive care should be prioritized.

Effect of Combination Vaccines on Hepatitis B Vaccine Compliance in Children in the United States

BACKGROUND

An increasingly crowded immunization schedule threatens the completion and compliance of hepatitis B vaccinations (HepB), the primary method of hepatitis B prevention. Combination vaccines have been proposed to alleviate this problem.

METHODS

Data from the 2011 National Immunization Survey Public-Use Data File were utilized (GSK study identifier: HO-11-770) to compare HepB completion and compliance rates between 3 groups of children: those who received HepB combination vaccine, those who received non-HepB combination vaccine and those who received HepB single-antigen vaccine only. Completion was defined as the accumulation of 3 HepB doses by 18 months. Compliance was defined as the receipt of vaccine doses within the Advisory Committee on Immunization Practices' recommended age ranges.

RESULTS

Of a sample of 4,040,116 children, 39.4% received a HepB combination vaccine, 43.0% received a non-HepB combination vaccine and 17.5% received a HepB single-antigen vaccine. Overall, 91.2% of children completed all 3 recommended doses, but only 61.8% completed them at age-appropriate times. Those receiving single-antigen only (odds ratio = 0.25, 95% confidence interval: 0.17-0.35) or non-HepB combination vaccines (odds ratio = 0.50, 95% confidence interval: 0.37-0.69) were substantially less likely to complete 3 doses of HepB than those who received the HepB combination vaccine.

CONCLUSIONS

Although completion rates were high, a large proportion of children did not receive HepB doses at age-appropriate times. Combination vaccine was associated with both higher completion and compliance outcomes compared with HepB single-antigen vaccine.

Timeliness and completeness of routine childhood vaccinations in children by two years of age in Alberta, Canada

OBJECTIVES

Assessing timeliness and completeness of vaccine administration is important for evaluating the effectiveness of immunization programs. Few studies have reported timeliness, particularly in Canada. The objective of this study was to examine timeliness of the receipt of vaccination for each routine childhood recommended vaccine by 24 months of age among children in a community-based pregnancy cohort in Calgary, Alberta.

METHODS

Survey data from a community-based pregnancy cohort in Alberta were linked to Public Health vaccination records of children (n = 2763). The proportion of children receiving early, timely, delayed, or no vaccination was calculated. A dose was considered early if it was administered before the recommended age in days as per the vaccination schedule, timely if administered at any time from start of recommended age in days to age in days when delay counts were initiated, and delayed if it was administered on or after age in days when delay counts were initiated. Series completion rates were also calculated.

RESULTS

For multi-dose vaccines, over 80% of children had timely doses at 2, 4 and 6 months. By 12 months, this proportion decreased to 65% (95% CI: 63%-66%) for meningococcal conjugate group C, 61% (95% CI: 59%-62%) for measles antigen-containing vaccines and 64% (95% CI: 62%-65%) for varicella antigen-containing vaccines. At 18 months, only 55% (95% CI: 53%-56%) of the children had a timely 4th dose of diphtheria, acellular pertussis, tetanus, polio, and Haemophilus influenzae type b vaccine. Eventual series completion rate for all recommended vaccines was 77% (95% CI: 75%-79%).

CONCLUSION

The timeliness and completeness of routine childhood vaccination in preschool children in this community-based pregnancy cohort is lower than provincial targets. Data on timeliness of vaccination can inform further work on barriers and enablers to vaccination in order to meet provincial targets.

Missed opportunities for simultaneous administration of the fourth dose of DTaP among children in the United States

BACKGROUND

Simultaneous administration of all age-appropriate doses of vaccines is an effective strategy for raising vaccination coverage. Vaccination coverage for ≥4 dose of DTaP (diphtheria, tetanus toxoids, and acellular pertussis vaccine) among children 19-35months in the United States has not reached the Healthy People 2020 target of 90%. Risk factors for missed opportunities for simultaneous administration of the fourth dose of DTaP have not been investigated.

METHODS

A missed opportunity for simultaneous administration of the fourth dose of DTaP is defined as the failure to administer an age-eligible fourth dose of DTaP, and during the same age-eligible period for the fourth dose of DTaP other recommended and age-appropriate doses of vaccines are given to children. This study used 2001-2014 National Immunization Survey data to describe the trend in missed opportunities for simultaneous administration of the fourth dose of DTaP from 2001 through 2014, assess the prevalence of children who missed opportunities for simultaneous administration of the fourth dose of DTaP by selected factors, and recognize significant risk factors for missed opportunities for simultaneous administration of the fourth dose of DTaP.

RESULTS

From 2001 to 2014, the prevalence of missed opportunities for simultaneous administration of the fourth dose of DTaP among children 19-35months in the United States ranged from 5.7% to 9.0%; across 13 factors considered, the prevalence of missed opportunities varied from 3.3% to 22.9%. Children who were late in receiving the first to third dose of DTaP had significantly higher prevalence of missed opportunities for simultaneous administration of the fourth dose of DTaP than children who received these doses on-time, with adjusted prevalence ratios for late vs. on-time of 1.7, 1.6, and 3.2, and all P-value<0.01.

CONCLUSIONS

Improving on-time vaccination of the third dose of DTaP could substantially reduce missed opportunities for simultaneous administration of the fourth dose of DTaP.

Spatial distribution of mumps in South Korea, 2001-2015: identifying clusters and population risk factors

In South Korea, the resurgence of mumps was noted primarily among school-aged children and adolescents since 2000. We analyzed spatial patterns in mumps incidence to give an indication to the geographical risk. We used National Notifiable Disease Surveillance System data from 2001 to 2015, classifying into three periods according to the level of endemicity. A geographic-weighted regression analysis was performed to find demographic predictors of mumps incidence according to district level. We assessed the association between the total population size, population density, percentage of children (age 0-19 years), timely vaccination rate of measles-mumps-rubella vaccines and the higher incidence rate of mumps. During low endemic periods, there were sporadic regional distributions of outbreak in the central and northern part of the country. During intermediate endemic periods, the increase of incidence was noted across the country. During high endemic period, a nationwide high incidence of mumps was noted especially concentrated in southwestern regions. A clear pattern for the mumps cluster shown through global spatial autocorrelation analysis from 2004 to 2015. The 'non-timely vaccination coverage' (P = 0·002), and 'proportion of children population' (P < 0·001) were the predictors for high mumps incidence in district levels. Our study indicates that the rate of mumps incidence according to geographic regions vary by population proportion and neighboring regions, and timeliness of vaccination, suggesting the importance of community-level surveillance and improving of timely vaccination.

Providing opportunistic immunisations for at-risk inpatients in a tertiary paediatric hospital

Attaining high immunisation coverage rates for children with medical conditions is vital. The Royal Children's Hospital (RCH) Immunisation Service has the opportunity to check each inpatient's immunisation status and provide opportunistic vaccines and/or bring the Australian Childhood Immunisation Register (ACIR) up-to-date. This paper highlights that during admission, one quarter of children were not up-to-date with routine scheduled immunisations and 42% of those inpatients due or overdue for immunisation were vaccinated. The model of establishing routine checking of immunisation records and reminding hospital staff about immunisation can result in improvements in vaccination coverage. Healthcare providers have a responsibility to check immunisation status and offer vaccines when necessary; however, often there are missed opportunities to immunise. This paper demonstrates that having a dedicated Immunisation Service, a partnership with a relevant government agency, and effective collaboration with inpatient clinical teams, opportunistic immunisation can be achieved for inpatients.

Vaccination Timeliness in Children Under India's Universal Immunization Program

BACKGROUND

India has the highest number of deaths among children younger than 5 years of age globally; the majority are from vaccine preventable diseases. Untimely vaccination unnecessarily prolongs susceptibility to disease and contributes to the burden of childhood morbidity and mortality, yet there is scarce literature on vaccination delays. The aim of this study is to characterize the timeliness of childhood vaccinations administered under India's routine immunization program using a novel application of an existing statistical methodology.

METHODS

This study utilized the district level household and facility survey data, 2008 from India using vaccination data from children with and without immunization cards. Turnbull estimator of the cumulative distribution function was used to estimate the probability of vaccination at each age. Timeliness of Bacille Calmette-Guerin (BCG), all 3 doses of diphtheria, pertussis and tetanus vaccine (DPT) and measles-containing vaccine (MCV) were considered for this analysis.

RESULTS

Vaccination data on 268,553 children who were 0-60 months of age were analyzed; timely administration of BCG, DPT3 and MCV occurred in 31%, 19% and 34% of children, respectively. The estimated vaccination probability plateaued for DPT and BCG around the age of 24 months, whereas MCV uptake increased another 5% after 24 months of age. The 5-year coverage of BCG, DPT3 and MCV in Indian children was 87%, 63% and 76%, respectively.

CONCLUSIONS

Lack of timely administration of key childhood vaccines, especially DPT3 and MCV, remains a major challenge in India and likely contributes to the significant burden of vaccine preventable disease-related morbidity and mortality in children.

What timing of vaccination is potentially dangerous for children younger than 2 years?

Vaccine-preventable diseases still occur although measured coverage rates at 2 y of age are high. The occurrence of these diseases may be explained in part by untimely, that is, late vaccination. Our objective was to identify potentially dangerous vaccination delays for each dose of each vaccine in children younger than 2 y. A 3-round Delphi process was conducted by e-mail. We recruited 37 French experts in vaccines for children: 16 from the Infovac-France group and 21 from the French study group for pediatric infectious diseases. Items were generated by a literature review for the 10 vaccine doses recommended before 2 y of age. Item reduction in round 1 and 2 and any consensus in round 3 used a 70% consensus cutoff. The mean participation rate was 79%. Delays that should not be exceeded were identified for all vaccine doses. The 70% consensus was reached for 6 of the 10 vaccine doses: 15 d after the recommended date for the first 2 doses of the diphtheria-tetanus-acellular pertussis-inactivated polio vaccine/Haemophilus influenzae b vaccine and for the second dose of the pneumococcal conjugate vaccine, 1 month for the meningococcal C vaccine and for the first dose of the measles-mumps-rubella vaccine, and 11 y of age for completion of the hepatitis B vaccination. This Delphi process identified potentially dangerous vaccination delays for children to the age of 2 y. These can be used as new indicators in further studies of vaccine effectiveness and can help to improve the quality of vaccine protection in children.

Does frequent residential mobility in early years affect the uptake and timeliness of routine immunisations? An anonymised cohort study

BACKGROUND

There are conflicting findings regarding the impact of residential mobility on immunisation status. Our aim was to determine whether there was any association between residential mobility and take up of immunisations and whether they were delayed in administration.

METHODS

We carried out a cohort analysis of children born in Wales, UK. Uptake and time of immunisation were collected electronically. We defined frequent movers as those who had moved: 2 or more times in the period prior to the final scheduled on-time date (4 months) for 5 in 1 vaccinations; and 3 or more times in the period prior to the final scheduled on-time date (12 months) for MMR, pneumococcal and meningitis C vaccinations. We defined immunisations due at 2-4 months delayed if they had not been given by age 1; and those due at 12-13 months as delayed if they had not been given by age 2.

RESULTS

Uptake rates of routine immunisations and whether they were given within the specified timeframe were high for both groups. There was no increased risk (odds ratios (95% confidence intervals) between frequent movers compared to non-movers for the uptake of: primary MMR 1.08 (0.88-1.32); booster Meningitis C 1.65 (0.93-2.92); booster pneumococcal 1.60 (0.59-4.31); primary 5 in 1 1.28 (0.92-1.78); and timeliness: primary MMR 0.92 (0.79-1.07); booster Meningitis C 1.26 (0.77-2.07); booster pneumococcal 1.69 (0.23-12.14); and primary 5 in 1 1.04 (0.88-1.23).

DISCUSSION

Findings suggest that children who move home frequently are not adversely affected in terms of the uptake of immunisations and whether they were given within a specified timeframe. Both were high and may reflect proactive behaviour in the primary healthcare setting to meet Government coverage rates for immunisation.

Methodological challenges in measuring vaccine effectiveness using population cohorts in low resource settings

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We discuss methodological challenges for evaluating vaccine effectiveness using cohorts.

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No single set of definitions or analytical approach can address all possible biases.

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Careful consideration of denominator, exposure and outcome definitions is needed.

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Sensitivity analyses are crucial to examine assumptions and explore subtle relationships.

Post-licensure real world evaluation of vaccine implementation is important for establishing evidence of vaccine effectiveness (VE) and programme impact, including indirect effects. Large cohort studies offer an important epidemiological approach for evaluating VE, but have inherent methodological challenges.

Since March 2012, we have conducted an open prospective cohort study in two sites in rural Malawi to evaluate the post-introduction effectiveness of 13-valent pneumococcal conjugate vaccine (PCV13) against all-cause post-neonatal infant mortality and monovalent rotavirus vaccine (RV1) against diarrhoea-related post-neonatal infant mortality. Our study sites cover a population of 500,000, with a baseline post-neonatal infant mortality of 25 per 1000 live births.

We conducted a methodological review of cohort studies for vaccine effectiveness in a developing country setting, applied to our study context. Based on published literature, we outline key considerations when defining the denominator (study population), exposure (vaccination status) and outcome ascertainment (mortality and cause of death) of such studies. We assess various definitions in these three domains, in terms of their impact on power, effect size and potential biases and their direction, using our cohort study for illustration. Based on this iterative process, we discuss the pros and cons of our final per-protocol analysis plan. Since no single set of definitions or analytical approach accounts for all possible biases, we propose sensitivity analyses to interrogate our assumptions and methodological decisions.

In the poorest regions of the world where routine vital birth and death surveillance are frequently unavailable and the burden of disease and death is greatest We conclude that provided the balance between definitions and their overall assumed impact on estimated VE are acknowledged, such large scale real-world cohort studies can provide crucial information to policymakers by providing robust and compelling evidence of total benefits of newly introduced vaccines on reducing child mortality.

Influenza vaccine: Delayed vaccination schedules and missed opportunities in children under 2 years old

INTRODUCTION

In Argentina respiratory disease is the third leading cause of death in children under 5 years. In 2011 influenza vaccination was included in the National Calendar for children between 6 and 24 months (two doses schedule). Influenza vaccine coverage for second dose was 46.1% in 2013. The aim was to determine the proportion of delayed schedules and missed opportunities, to assess the characteristics of missed opportunities for vaccination and to explore the perception of influenza disease and vaccination from the parents of children between 6 and 24 months in different regions of Argentina in 2013.

METHODS

Analytical observational multicenter cross-sectional study. Structured surveys were carried out to the children's parents who were between 6 and 24 months of age during the influenza virus vaccination season (April-October 2013). Chi-Square test was used to assess association and differences between proportions and categorical variables. A logistic regression model was built to identify delay predictor variables in the vaccination schedules. Missed opportunities for vaccination were characterized through the estimation of proportions.

RESULTS

1350 surveys were conducted in the three centers. We detected 65% (884/1340) of delayed influenza vaccination schedules, 97% of them associated with missed opportunities of vaccination. The independent protective factors associated with a decreases risk of delayed schedules were: (a) perception of the importance of influenza vaccination (OR=0.42(0.18-0.94); p=0.035), (b) having less than one year of age (OR=0.75(0.59-0.96); p=0.022), (c) to have received information in pediatric visits or in any media (OR=0.71(0.56-0.90); p=0.004). There was 38% of MOIV in 1st dose and 63.4% in 2nd dose. The main cause of MOIV in 1st dose was not detecting the need for vaccination (39%) and in 2nd dose the unknowledge of the vaccination schedule (35.3%). No cultural reasons were detected.

CONCLUSIONS

High frequency of delayed vaccination schedules and missed opportunities were detected. Parents had little concern about the safety of influenza vaccine.

Immunizations: vaccinations in general

The childhood immunization schedule is complex and nuanced. Although serious adverse reactions to immunizations are uncommon, clinicians must be well-versed in these reactions as well as the contraindications and precautions to each vaccine. • Conjugate vaccine technology links polysaccharide antigens to carrier proteins, triggering T-cell-dependent immunity to polysaccharides, thereby strengthening immune memory. • On the basis of some research evidence and consensus, live vaccines are generally contraindicated in immunocompromised patients and in pregnancy. Most live vaccines can be administered to household contacts of immunocompromised patients. • On the basis of some research and consensus, modified administration of meningococcal, pneumococcal, and less commonly, other vaccines may be indicated to protect immunocompromised patients. • On the basis of disease epidemiology and consensus, international travelers should be up-to-date with all routine immunizations; depending on destination, additional vaccines or immune globulin may be required.

Risk Factors Associated with Children Missing the Fourth Dose of DTaP Vaccination

BACKGROUND

In 2012, reported pertussis reached the highest number of cases (48,277) in the United States since 1955.

OBJECTIVES

Estimate the prevalence of children who missed the fourth dose of DTaP (Diphtheria and Tetanus toxoids and acellular Pertussis vaccine) by parents' confidences in vaccines and influences from providers, the timeliness of the first through the third dose of DTaP, and selected socio-demographic characteristics; identify the significant risk factors for non-receipt of the fourth dose of DTaP; and evaluate the unadjusted and adjusted risk ratios for missing the fourth dose of DTaP.

METHODS

Data from 16,919 children 19-35 months living in the United States included in the 2011 National Immunization Survey were analyzed. Weighted categorical data analysis and multivariable regression in the context of complex sample survey were applied to assess the prevalence and to determine the independent risk factors.

RESULTS

Overall, 14.7% of children missed the fourth dose of DTaP. Children who were late in receiving the third dose of DTaP had significantly higher risk of missing the fourth dose of DTaP than children who were on-time in receiving the third dose of DTaP (adjusted risk ratio (RR) 2.48; 95%CI (1.92, 3.20)). The risk of missing the fourth dose of DTaP was 62% higher among children whose parents reported they didn't have a good relationship with their child's health-care providers than children whose parents reported having good relationship. Compared with the risk of missing the fourth dose of DTaP among children whose parents were confident in the value of vaccines, the risk was significantly higher for the children whose parents lacked confidence (adjusted RR 1.41; 95%CI (1.05, 1.89)).

CONCLUSIONS

Timeliness in receiving the first through the third dose of DTaP, influences from providers, and parents' confidence in the value of vaccines are the five significant risk factors for missing the fourth dose of DTaP vaccination. They are all modifiable. Future interventions to improve parental relationships with providers and attitudes toward vaccines could help improve pertussis vaccination coverage.

Maternal determinants of timely vaccination coverage among infants in rural Bangladesh

BACKGROUND

Timely vaccination, i.e., the receipt of all scheduled vaccinations in an age-appropriate fashion, is critical for the prevention of deadly diseases in infants and achievement of the UN Millennium Development Goal to reduce infant mortality. Infants, especially in rural or underprivileged settings often receive delayed vaccinations leaving them susceptible to vaccine-preventable illnesses early in the first year of life. In this study, we examined rates of timely vaccination among 24,435 infants born in Gaibandha and Rangpur rural districts of Bangladesh from 2001 to 2007.

METHODS

Vaccinations due by 14 weeks of age and administered through routine government immunization services were assessed using interviews with enrolled mothers between 11 and 18 weeks postpartum. We created a Timely Vaccination (TV) score to classify infants as vaccinated fully and on schedule (TV=1) or not (TV=0), and used multivariable logistic regression to identify maternal characteristics associated with infant's timely vaccination status.

RESULTS

Our results suggest that only 19% of infants in this cohort received scheduled vaccinations on time by 11-18 weeks postpartum. Mothers' engagement in paid employment [OR=1.13, 95% CI: 1.03-1.23], receipt of tetanus toxoid vaccination [OR=1.24, 95% CI: 1.11-1.38], history of antenatal care [OR=1.22, 95% CI: 1.12-1.32], or higher socioeconomic status [OR=1.07, 95% CI: 1.03-1.11] were positively associated with timely vaccination of their infants. Mother's perception of small infant size at birth was negatively associated with timely vaccination [OR=0.89, 95% CI: 0.82-0.97].

CONCLUSION

Timely vaccination coverage of infants in rural Gaibandha and Rangpur districts is extremely low. This analysis identifies important shortcomings associated with the 1-year vaccination benchmark of routine immunization performance and suggests the need for specific interventions based on potential maternal determinants as well as known system and programmatic barriers of timely vaccination among infants in rural Bangladesh.

Frequency and erroneous usage of temporary medical exemptions and knowledge of immunization guidelines among some Miami-Dade County Florida providers

OBJECTIVE

We assessed knowledge and practices regarding immunization guidelines and the Florida Certificate of Immunization (DH-680) based on FL-DOH and CDC recommendations, to identify the cause of the increasing number of erroneously issued temporary medical exemptions (TME) among selected health care providers in Miami-Dade County Florida.

METHODOLOGY

After reviewing immunization certificates from all public schools, a list of physicians who improperly issued 3 or more TMEs, defined as one given to a child who was up to date for their kindergarten and seventh grade requirements, was compiled. The DOH-Miami-Dade developed educational materials and questionnaires, and conducted face-to-face interviews and interventions during site visits to these providers (n=134). Data was analyzed using SAS 9.2.

RESULTS

Of the 104 questionnaires completed, 4 (3.85%) had correct answers to all 10 vaccine knowledge and practice related questions, while 10 (9.62%) had 7 or more incorrect answers. Frequently missed questions included: the required doses of varicella vaccine for seventh grade students entering the 2011-12 school year (86, 82.7%) and the proper scenario for issuing a TME (57, 54.8%).

CONCLUSIONS

In order to eliminate the improper use of TMEs, long-term efforts are needed to provide immunization-related educational materials and trainings to the medical community regarding vaccinations. These findings also suggest a need for enhanced explanation in multiple languages on the current Florida Immunization Certificate. Due to enhanced surveillance and education, the number of TMEs for kindergarten and seventh grade students was reduced by 12% and 4.9%, respectively, during the 2011 and 2012 school year.

Influenza vaccination of Michigan children by provider type, 2010-2011

BACKGROUND

Influenza vaccination for all children aged 6 months to 18 years has been recommended since 2008 to prevent flu-related morbidity and mortality. However, 2010-2011 influenza vaccine coverage estimates show under-vaccination in children of all ages. We examined predictors of influenza vaccination in Michigan during the 2010-2011 influenza season.

PURPOSE

To determine whether immunization provider type was associated with a child's influenza vaccination in Michigan and assess whether county-level factors were confounders of the association.

METHODS

Influenza vaccinations reported to the Michigan Care Improvement Registry from the 2010-2011 influenza season were analyzed in 2012 to estimate ORs for the association between immunization provider type and influenza vaccination.

RESULTS

Among 2,373,826 Michigan children aged 6 months through 17 years, 17% were vaccinated against influenza and lower vaccination rates were observed for public compared to private providers (13% vs 18%). In the unadjusted model, public providers had lower odds of vaccinating children compared to private providers (OR=0.60, 95% CI=0.60, 0.61). County-level factors, including percentage of families living below the poverty line, median household income, and percentage black race, were not shown to confound the association. In the adjusted models, public providers had lower odds of vaccinating children compared to private providers (OR=0.87, 95% CI=0.86, 0.88).

CONCLUSIONS

Although a child's likelihood of influenza vaccination in Michigan varies by provider type, more effective strategies to improve influenza vaccination rates for all Michigan children are needed.

Rotavirus vaccination compliance and completion in a Medicaid infant population

We examined completion and compliance rates of rotavirus (RV) vaccination according to the recommendations of the Advisory Committee on Immunization Practices (ACIP) and the Food and Drug Administration approved Prescribing Information (PI) for Rotarix® (RV1, GlaxoSmithKline Vaccines) and RotaTeq® (RV5, Merck and Co.) among infants under one year of age covered by Medicaid programs. Healthcare claims data from state Medicaid programs that constituted the Truven Health MarketScan® Multi-State Medicaid Database were retrieved from May 2008-June 2012. Infants were grouped under PI and ACIP cohorts based on the dosing regimens followed. The overall compliance per PI (n=673,956) and ACIP (n=695,612) recommendations were 24.5% and 28.2%, respectively; completion rates were 30.3% and 32.6%, respectively. In the PI cohort, infants who received RV1 had significantly higher compliance as compared with infants who received RV5 (65.2% vs. 31.3%; p<0.0001); completion rates among infants receiving RV1 and RV5 were 65.3% and 46.4%, respectively (p<0.0001). In the ACIP cohort, compliance with RV1 was significantly higher than RV5 (68.8% vs. 45.9%; p<0.0001) as was the overall completion rate (73.5% vs. 48.8%; p<0.0001). While compliance is increasing year over year, overall compliance of RV vaccines is suboptimal, with over 40% of eligible infants unvaccinated in both populations. The 2-dose RV vaccine showed better completion rates and higher compliance than the 3-dose RV vaccine in the United States. Public health initiatives focusing on suboptimal compliance and completion rates of RV vaccination in the Medicaid population could improve these metrics, thereby offering protection against RV infection.