Global routine vaccination coverage, 2014

Recent advances in nano- and micro-scale carrier systems for controlled delivery of vaccines

Vaccines provide substantial safety against infectious diseases, saving millions of lives each year. The recent COVID-19 pandemic highlighted the importance of vaccination in providing mass-scale immunization against outbreaks. However, the delivery of vaccines imposes a unique set of challenges due to their large molecular size and low room temperature stability. Advanced biomaterials and delivery systems such as nano- and mciro-scale carriers are becoming critical components for successful vaccine development. In this review, we provide an updated overview of recent advances in the development of nano- and micro-scale carriers for controlled delivery of vaccines, focusing on carriers compatible with nucleic acid-based vaccines and therapeutics that emerged amid the recent pandemic. We start by detailing nano-scale delivery systems, focusing on nanoparticles, then move on to microscale systems including hydrogels, microparticles, and 3D printed microneedle patches. Additionally, we delve into emerging methods that move beyond traditional needle-based applications utilizing innovative delivery systems. Future challenges for clinical translation and manufacturing in this rapidly advancing field are also discussed.

Incomplete immunization and its determinants among children in Africa: Systematic review and meta-analysis

Immunization is one of the most cost-effective measures to prevent morbidity and mortality in children. Therefore, the purpose of this systematic review and meta-analysis was to determine the pooled prevalence of incomplete immunization among children in Africa as well as its determinants. PubMed, Google Scholar, Scopus, Science Direct, and online institutional repository homes were searched. Studies published within English language, with full text available for searching, and studies conducted in Africa were included in this meta-analysis. A pooled prevalence, Sub-group analysis, sensitivity analysis and meta-regression were conducted. Out of 1305 studies assessed, 26 met our criteria and were included in this study. The pooled prevalence of incomplete immunization was 35.5% (95% CI: 24.4, 42.7), I² = 92.1%). Home birth (AOR=2.7; 95% CI: 1.5-4.9), rural residence (AOR = 4.6; 95% CI: 1.1-20.1), lack of antenatal care visit (AOR = 2.6; 95% CI: 1.4-5.1), lack of knowledge of immunizations (AOR=2.4; 95% CI: 1.3-4.6), and maternal illiteracy (AOR = 1.7: 95%CI: 1.3-2.0) were associated with incomplete immunization. In Africa, the prevalence of incomplete immunization is high. It is important to promote urban residency, knowledge of immunization and antenatal follow up care.

Vaccination dropout among children in Sub-Saharan Africa: Systematic review and meta-analysis

Immunization is cost-effective preventive strategy for child morbidity and mortality. PubMed, Google Scholar, Scopus, Science Direct, and online institutional repository homes were searched. Data were extracted by Microsoft excel. Begg's rank test, and Egger's regression test was done. A pooled prevalence, Sub-group analysis, sensitivity analysis and meta-regression were conducted. A total of 12 articles were included in this study. The pooled prevalence of vaccination dropout was 26.06% (95% CI: 11.59, 30.53), I2 =91.2%. In sub-group analysis, Nigeria had the highest prevalence of immunization dropouts (33.59%). It was 18.01% and 29.25%, respectively, for published and unpublished research. Community-based studies and institutional-based studies also yield a prevalence of dropout 39.04% and 13.73% respectively. Dropout rate was 22.66% for sample sizes under 500 and 18.01% for sample sizes beyond 500. In Sub-Saharan Africa, the prevalence of vaccination dropout was high. Community education about vaccinations importance should be prioritized.

Pentavalent vaccination in Kenya: coverage and geographical accessibility to health facilities using data from a community demographic and health surveillance system in Kilifi County

Background

There is substantial evidence that immunization is one of the most significant and cost-effective pillars of preventive and promotive health interventions. Effective childhood immunization coverage is thus essential in stemming persistent childhood illnesses. The third dose of pentavalent vaccine for children is an important indicator for assessing performance of the immunisation programme because it mirrors the completeness of a child’s immunisation schedule. Spatial access to an immunizing health facility, especially in sub-Sahara African (SSA) countries, is a significant determinant of Pentavalent 3 vaccination coverage, as the vaccine is mainly administered during routine immunisation schedules at health facilities. Rural areas and densely populated informal settlements are most affected by poor access to healthcare services. We therefore sought to determine vaccination coverage of Pentavalent 3, estimate the travel time to health facilities offering immunisation services, and explore its effect on immunisation coverage in one of the predominantly rural counties on the coast of Kenya.

Methods

We used longitudinal survey data from the health demographic surveillance system implemented in Kaloleni and Rabai Sub-counties in Kenya. To compute the geographical accessibility, we used coordinates of health facilities offering immunisation services, information on land cover, digital elevation models, and road networks of the study area. We then fitted a hierarchical Bayesian multivariable model to explore the effect of travel time on pentavalent vaccine coverage adjusting for confounding factors identified a priori.

Results

Overall coverage of pentavalent vaccine was at 77.3%. The median travel time to a health facility was 41 min (IQR = 18–65) and a total of 1266 (28.5%) children lived more than one-hour of travel-time to a health facility. Geographical access to health facilities significantly affected pentavalent vaccination coverage, with travel times of more than one hour being significantly associated with reduced odds of vaccination (AOR = 0.84 (95% CI 0.74 – 0.94).

Conclusion

Increased travel time significantly affects immunization in this rural community. Improving road networks, establishing new health centres and/or stepping up health outreach activities that include vaccinations in hard-to-reach areas within the county could improve immunisation coverage. These data may be useful in guiding the local department of health on appropriate location of planned immunization centres.

Full immunization coverage and associated factors among children age 12-23 months in Ethiopia: systematic review and meta-analysis of observational studies

Background: Millions of children in developing countries remained unvaccinated and under-vaccinated. This study was aimed to determine the pooled full vaccination coverage and associated factors in Ethiopia.Methods: This review and meta-analysis were included observational studies conducted from 2013 to 2020. The international online databases as well as gray literatures were retrieved from April 15 to 30/2020. The quality of each study was assessed using the Newcastle-Ottawa Quality Assessment Scale (NOS). Data were extracted using Microsoft excel 2016 and analyzed using STATA 11.0 statistical software. Heterogeneity among studies was assessed using the Cochran Q statistics and I² test. The pooled effect sizes were determined using pooled proportion for the full vaccination coverage and odds ratios for the associated factors with the corresponding 95% confidence interval.Result: Sixteen studies with 8305 children aged 12-23 months were included. The overall pooled full vaccination coverage was 65% (95% CI: 56%-74%). Institutional delivery (OR: 2.12, 95% CI: 1.78-2.52), travel to vaccination site for <2 hours (OR: 2.43, 95%CI: 1.97-3.00), received at least one antenatal (ANC) visit (OR: 3.2, 95%CI: 2.46-4.1), good maternal knowledge of immunization (OR: 3.63, 95%CI: 2.82-4.67), being informed on immunization schedule (OR: 2.54, 95%CI: 2.02-3.2), living in urban areas (OR: 2, 95% CI: 1.54-2.6), and a household visit by health-care providers during the postnatal period (OR: 2.23, 95%CI: 1.22-4.09) were the independent predictors of full immunization coverage among children age 12-23 months.Conclusion: The study showed that the pooled full immunization coverage is still far from the national target (90%). Therefore, the government should strengthen both the outreach and facility-based immunization services.

Timeliness and completeness of routine childhood vaccinations in young children residing in a district with recurrent vaccine-preventable disease outbreaks, Jerusalem, Israel

BackgroundChildhood vaccination schedules recommend vaccine doses at predefined ages.AimWe evaluated vaccination completeness and timeliness in Jerusalem, a district with recurrent vaccine-preventable disease outbreaks.MethodsVaccination coverage was monitored by the up-to-date method (vaccination completeness at age 2 years). Timeliness of vaccination was assessed in children (n = 3,098, born in 2009, followed to age 48 months, re-evaluated at age 7 years) by the age-appropriate method (vaccine dose timeliness according to recommended schedule). Vaccines included: hepatitis B (HBV: birth, 1 month and 6 months); diphtheria, tetanus, acellular pertussis, polio, Haemophilus influenzae b (DTaP-IPV-Hib: 2, 4, 6 and 12 months); pneumococcal conjugate (PCV: 2, 4 and 12 months); measles-mumps-rubella/measles-mumps-rubella-varicella (MMR/MMRV: 12 months) and hepatitis A (HAV: 18 and 24 months).ResultsOverall vaccination coverage (2014 cohort evaluated at age 2 years) was 95% and 86% for MMR/MMRV and DTaP-IPV-Hib4, respectively. Most children (94%, 91%, 79%, 95%, 92% and 82%) were up-to-date for HBV3, DTaP-IPV-Hib4, PCV3, MMR/MMRV1, HAV1 and HAV2 vaccines at 48 months, but only 32%, 28%, 38%, 58%, 49% and 20% were vaccinated timely (age-appropriate). At age 7 years, the median increase in vaccination coverage was 2.4%. Vaccination delay was associated with: high birth order, ethnicity (higher among Jews vs Arabs), birth in winter, delayed acceptance of first dose of DTaP-IPV-Hib and multiple-dose vaccines (vs MMR/MMRV). Jewish ultra-Orthodox communities had low vaccination coverage.ConclusionsConsiderable vaccination delay should be addressed within the vaccine hesitancy spectrum. Delays may induce susceptibility to vaccine-preventable disease outbreaks; tailored programmes to improve timeliness are required.

Pertussis in Latin America and the Hispanic Caribbean: a systematic review

Introduction: Pertussis in Latin America continues to cause periodic epidemics with substantial morbidity particularly among young children. The disease has persisted despite long-standing vaccination programs in the region. Areas covered: We conducted a systematic review to characterize the recent epidemiology of pertussis in Latin America and Hispanic Caribbean. We undertook a holistic approach and attempted to include all available data concerning pertussis that may explain the changing dynamics of the disease. Expert opinion: There are wide disparities in the reported annual incidence rates of pertussis both within and between countries in the region. General trends in pertussis incidence are difficult to ascertain due to the heterogeneity in the epidemiological data. Available data suggests that the disease burden has changed over the years such that now it predominantly affects those <1 year. Coverage with three doses of the pertussis vaccine has been highly variable, and very few countries have consistently achieved ≥90% coverage annually since 2000. There remain inequalities in vaccination coverage in some regions/localities and specific groups, which sustains the risk of pertussis dissemination. The WHO considers that maternal pertussis immunization provides protection to infants too young to be vaccinated; >10 Latin American countries currently recommend vaccination of pregnant women.

Acute Infections That Produce Upper Airway Obstruction

This chapter discusses the common and potentially serious infective causes of acute upper airway obstruction in children. The laryngeal anatomy of young children makes them particularly susceptible to upper airway obstruction, and during acute infections this is exacerbated by inflammation and edema of the airway mucosa. The most common cause of infective upper airway obstruction in children is viral laryngotracheobronchitis, or croup, which is usually a mild and self-limiting illness, but management with corticosteroids may still be necessary. Bacterial causes of upper airway obstruction have fortunately become rare since the introduction of the Haemophilus influenzae B (HiB) immunization, but a few cases of epiglottitis do still occur due to nonimmunization, vaccine failure, and infection with non-HiB organisms. These cases constitute a medical emergency due to the risk of rapid progression to complete airway obstruction. Other rare conditions are discussed including bacterial tracheitis, diphtheria, retropharyngeal, and peritonsillar abscesses. Key learning points in this chapter include the main discriminating factors of the various causes of infective upper airway obstruction, the importance of a calm and minimally distressing approach to the child presenting with stridor, and the need for early anesthetic team involvement in cases with a suspected bacterial etiology or signs of impending airway obstruction.

Coverage and timeliness of vaccination and the validity of routine estimates: Insights from a vaccine registry in Kenya

BACKGROUND

The benefits of childhood vaccines are critically dependent on vaccination coverage. We used a vaccine registry (as gold standard) in Kenya to quantify errors in routine coverage methods (surveys and administrative reports), to estimate the magnitude of survivor bias, contrast coverage with timeliness and use both measures to estimate population immunity.

METHODS

Vaccination records of children in the Kilifi Health and Demographic Surveillance System (KHDSS), Kenya were combined with births, deaths, migration and residence data from 2010 to 17. Using inverse survival curves, we estimated up-to-date and age-appropriate vaccination coverage, calculated mean vaccination coverage in infancy as the area under the inverse survival curves, and estimated the proportion of fully immunised children (FIC). Results were compared with published coverage estimates. Risk factors for vaccination were assessed using Cox regression models.

RESULTS

We analysed data for 49,090 infants and 48,025 children aged 12-23 months in 6 birth cohorts and 6 cross-sectional surveys respectively, and found 2nd year of life surveys overestimated coverage by 2% compared to birth cohorts. Compared to mean coverage in infants, static coverage at 12 months was exaggerated by 7-8% for third doses of oral polio, pentavalent (Penta3) and pneumococcal conjugate vaccines, and by 24% for the measles vaccine. Surveys and administrative coverage also underestimated the proportion of the fully immunised child by 10-14%. For BCG, Penta3 and measles, timeliness was 23-44% higher in children born in a health facility but 20-37% lower in those who first attended during vaccine stock outs.

CONCLUSIONS

Standard coverage surveys in 12-23 month old children overestimate protection by ignoring timeliness, and survivor and recall biases. Where delayed vaccination is common, up-to-date coverage will give biased estimates of population immunity. Surveys and administrative methods also underestimate FIC prevalence. Better measurement of coverage and more sophisticated analyses are required to control vaccine preventable diseases.

Public subsidies and the recommendation of child vaccines among primary care physicians: a nationwide cross-sectional study in Japan

OBJECTIVE

Although public subsidies and physician recommendations for vaccination play key roles in increasing childhood vaccination coverage, the association between them remains uncertain. This study aimed to identify the association between awareness of public subsidies and recommendations for Haemophilus influenzae type b (Hib), Streptococcus pneumoniae (pneumococcal conjugate vaccine (PCV)) and human papillomavirus (HPV) vaccinations among primary care physicians in Japan.

DESIGN

This is a cross-sectional study.

SETTING

In 2012, a questionnaire was distributed among 3000 randomly selected physicians who were members of the Japan Primary Care Association.

PARTICIPANTS

From the questionnaire, participants were limited to physicians who administered childhood vaccinations.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary measures were participants' awareness of public subsidies and their recommendation levels for Hib, PCV and HPV vaccines. Multiple logistic regression analysis was performed to investigate the association between awareness and recommendation, with adjustment for possible confounders.

RESULTS

The response rate was 25.8% (743/2880). Of 743 physician respondents, 434 were included as analysis subjects. The proportions of those who recommended vaccinations were 57.1% for Hib, 54.1% for PCV and 58.1% for HPV. For each vaccine, multivariable analyses showed physicians who were aware of the subsidy were more likely to recommend vaccination than those who were not aware: the adjusted ORs were 4.21 (95% CI 2.47 to 7.15) for Hib, 4.96 (95% CI 2.89 to 8.53) for PCV and 4.17 (95% CI 2.00 to 8.70) for HPV.

CONCLUSIONS

Primary care physicians' awareness of public subsidies was found to be associated with their recommendations for the Hib, PCV and HPV vaccines. Provision of information about public subsidies to these physicians may increase their likelihood to recommend vaccination.

Microorganisms Associated With Pneumonia in Children <5 Years of Age in Developing and Emerging Countries: The GABRIEL Pneumonia Multicenter, Prospective, Case-Control Study

Background

Pneumonia, the leading infectious cause of child mortality globally, mainly afflicts developing countries. This prospective observational study aimed to assess the microorganisms associated with pneumonia in children aged <5 years in developing and emerging countries.

Methods

A multicenter, case-control study by the GABRIEL (Global Approach to Biological Research, Infectious diseases and Epidemics in Low-income countries) network was conducted between 2010 and 2014 in Cambodia, China, Haiti, India (2 sites), Madagascar, Mali, Mongolia, and Paraguay. Cases were hospitalized children with radiologically confirmed pneumonia; controls were children from the same setting without any features suggestive of pneumonia. Nasopharyngeal swabs were collected from all subjects; 19 viruses and 5 bacteria were identified by reverse-transcription polymerase chain reaction. Associations between microorganisms and pneumonia were quantified by calculating the adjusted population attributable fraction (aPAF) after multivariate logistic regression analysis adjusted for sex, age, time period, other pathogens, and site.

Results

Overall, 888 cases and 870 controls were analyzed; ≥1 microorganism was detected in respiratory samples in 93.0% of cases and 74.4% of controls (P < .001). Streptococcus pneumoniae, Mycoplasma pneumoniae, human metapneumovirus, rhinovirus, respiratory syncytial virus (RSV), parainfluenza virus 1, 3, and 4, and influenza virus A and B were independently associated with pneumonia; aPAF was 42.2% (95% confidence interval [CI], 35.5%-48.2%) for S. pneumoniae, 18.2% (95% CI, 17.4%-19.0%) for RSV, and 11.2% (95% CI, 7.5%-14.7%) for rhinovirus.

Conclusions

Streptococcus pneumoniae, RSV, and rhinovirus may be the major microorganisms associated with pneumonia infections in children <5 years of age from developing and emerging countries. Increasing S. pneumoniae vaccination coverage may substantially reduce the burden of pneumonia among children in developing countries.

A case of respiratory toxigenic diphtheria: contact tracing results and considerations following a 30-year disease-free interval, Catalonia, Spain, 2015

In May 2015, following a 30-year diphtheria-free interval in Catalonia, an unvaccinated 6-year-old child was diagnosed with diphtheria caused by toxigenic Corynebacterium diphtheriae. After a difficult search for equine-derived diphtheria antitoxin (DAT), the child received the DAT 4 days later but died at the end of June. Two hundred and seventeen contacts were identified in relation to the index case, and their vaccination statuses were analysed, updated and completed. Of these, 140 contacts underwent physical examination and throat swabs were taken from them for analysis. Results were positive for toxigenic C. diphtheriae in 10 contacts; nine were asymptomatic vaccinated children who had been in contact with the index case and one was a parent of one of the nine children. Active surveillance of the 217 contacts was initiated by healthcare workers from hospitals and primary healthcare centres, together with public health epidemiological support. Lack of availability of DAT was an issue in our case. Such lack could be circumvented by the implementation of an international fast-track procedure to obtain it in a timely manner. Maintaining primary vaccination coverage for children and increasing booster-dose immunisation against diphtheria in the adult population is of key importance.

Prevalence of hepatitis D virus infection in sub-Saharan Africa: a systematic review and meta-analysis

BACKGROUND

Hepatitis D virus (also known as hepatitis delta virus) can establish a persistent infection in people with chronic hepatitis B, leading to accelerated progression of liver disease. In sub-Saharan Africa, where HBsAg prevalence is higher than 8%, hepatitis D virus might represent an important additive cause of chronic liver disease. We aimed to establish the prevalence of hepatitis D virus among HBsAg-positive populations in sub-Saharan Africa.

METHODS

We systematically reviewed studies of hepatitis D virus prevalence among HBsAg-positive populations in sub-Saharan Africa. We searched PubMed, Embase, and Scopus for papers published between Jan 1, 1995, and Aug 30, 2016, in which patient selection criteria and geographical setting were described. Search strings included sub-Saharan Africa, the countries therein, and permutations of hepatitis D virus. Cohort data were also added from HIV-positive populations in Malawi and Ghana. Populations undergoing assessment in liver disease clinics and those sampled from other populations (defined as general populations) were analysed. We did a meta-analysis with a DerSimonian-Laird random-effects model to calculate a pooled estimate of hepatitis D virus seroprevalence.

FINDINGS

Of 374 studies identified by our search, 30 were included in our study, only eight of which included detection of hepatitis D virus RNA among anti-hepatitis D virus seropositive participants. In west Africa, the pooled seroprevalence of hepatitis D virus was 7·33% (95% CI 3·55-12·20) in general populations and 9·57% (2·31-20·43) in liver-disease populations. In central Africa, seroprevalence was 25·64% (12·09-42·00) in general populations and 37·77% (12·13-67·54) in liver-disease populations. In east and southern Africa, seroprevalence was 0·05% (0·00-1·78) in general populations. The odds ratio for anti-hepatitis D virus detection among HBsAg-positive patients with liver fibrosis or hepatocellular carcinoma was 5·24 (95% CI 2·74-10·01; p<0·0001) relative to asymptomatic controls.

INTERPRETATION

Findings suggest localised clusters of hepatitis D virus endemicity across sub-Saharan Africa. Epidemiological data are needed from southern and east Africa, and from patients with established liver disease. Further studies should aim to define the reliability of hepatitis D virus testing methods, identify risk factors for transmission, and characterise the natural history of the infection in the region.

FUNDING

Wellcome Trust, Royal Society.

Using best-worst scaling to rank factors affecting vaccination demand in northern Nigeria

BACKGROUND

Understanding and ranking the reasons for low vaccination uptake among parents in northern Nigeria is critical to implement effective policies to save lives and prevent illnesses. This study applies best-worst scaling (BWS) to rank various factors affecting parents' demand for routine childhood immunization.

METHODS

We conducted a household survey in Nahuche, Zamfara State in northern Nigeria. Nearly two hundred parents with children under age five were asked about their views on 16 factors using a BWS technique. These factors focused on known attributes that influence the demand for childhood immunization, which were identified from a literature review and reviewed by a local advisory board. The survey systematically presented parents with subsets of six factors and asked them to choose which they think are the most and least important in decisions to vaccinate children. We used a sequential best-worst analysis with conditional logistic regression to rank factors.

RESULTS

The perception that vaccinating a child makes one a good parent was the most important motivation for parents in northern Nigeria to vaccinate children. Statements related to trust and social norms were ranked higher in importance compared to those that highlighted perceived benefits and risks, healthcare service, vaccine information, or opportunity costs. Fathers ranked trust in the media and views of their leaders to be of greatest importance, whereas mothers placed greater importance on social perceptions and norms. Parents of children without routine immunization ranked their trust in local leaders about vaccines higher in considerations, and the media's views lower, compared to parents with children who received routine immunization.

CONCLUSIONS

Framing immunization messages in the context of good parenting and hearing these messages from trusted information sources may motivate parental uptake of childhood vaccines. These results are useful to policymakers to prioritize resources in order to increase awareness and demand for childhood immunization.

Maternal nutritional status during pregnancy and infant immune response to routine childhood vaccinations

To systematically review the association between maternal nutritional status in pregnancy and infant immune response to childhood vaccines. We reviewed literature on maternal nutrition during pregnancy, fetal immune system and vaccines and possible relationships. Thereafter, we undertook a systematic review of the literature of maternal nutritional status and infant vaccine response, extracted relevant information, assessed quality of the nine papers identified and present findings in a narrative format. From limited evidence of average quality, intrauterine nutrition deficiency could lead to functional deficit in the infant's immune function; child vaccine response may thus be negatively affected by maternal malnutrition. Response to childhood vaccination may be associated with fetal and early life environment; evaluation of programs should take this into account.

Knowledge, Attitudes and Perceptions About Routine Childhood Vaccinations Among Jewish Ultra-Orthodox Mothers Residing in Communities with Low Vaccination Coverage in the Jerusalem District

Background and aims Childhood vaccinations are an important component of primary prevention. Maternal and Child Health (MCH) clinics in Israel provide routine vaccinations without charge. Several vaccine-preventable-diseases outbreaks (measles, mumps) emerged in Jerusalem in the past decade. We aimed to study attitudes and knowledge on vaccinations among mothers, in communities with low immunization coverage. Methods A qualitative study including focus groups and semi-structured interviews. Results Low immunization coverage was defined below the district's mean (age 2 years, 2013) for measles-mumps-rubella-varicella 1st dose (MMR1\MMRV1) and diphtheria-tetanus-pertussis 4th dose (DTaP4), 96 and 89%, respectively. Five communities were included, all were Jewish ultra-orthodox. The mothers' (n = 87) median age was 30 years and median number of children 4. Most mothers (94%) rated vaccinations as the main activity in the MCH clinics with overall positive attitudes. Knowledge about vaccines and vaccination schedule was inadequate. Of vaccines scheduled at ages 0-2 years (n = 13), the mean number mentioned was 3.9 ± 2.8 (median 4, range 0-9). Vaccines mentioned more often were outbreak-related (measles, mumps, polio) and HBV (given to newborns). Concerns about vaccines were obvious, trust issues and religious beliefs were not. Vaccination delay was very common and timeliness was considered insignificant. Practical difficulties in adhering to the recommended schedule prevailed. The vaccinations visits were associated with pain and stress. Overall, there was a sense of self-responsibility accompanied by inability to influence others. Conclusion Investigating maternal knowledge and attitudes on childhood vaccinations provides insights that may assist in planning tailored intervention programs aimed to increase both vaccination coverage and timeliness.

Age-appropriate versus up-to-date coverage of routine childhood vaccinations among young children in Israel

BACKGROUND AND AIMS

Routine childhood vaccinations schedules recommend that children receive the vaccine doses at specific ages. Vaccination coverage data are conventionally reported by the up-to-date method. We aimed to assess vaccination timeliness by the age-appropriate method and compare with the up-to-date vaccination coverage.

METHODS

Assessment of age-appropriate and up-to-date vaccination coverage among children born in Israel in 2009 and followed to age 48 months (national representative sample, n = 3892). The vaccinations included: Hepatitis B vaccine (HBV), Diphtheria-Tetanus-acellular Pertussis-Polio-Haemophilus-influenzae-b (DTaP-IPV-Hib), Pneumococcal conjugate vaccine (PCV), Measles-mumps-rubella-varicella vaccine (MMR/MMRV) and Hepatitis A vaccine (HAV). The categories defined: age-appropriate (at the recommended age and up to 1 month), delayed less than 6 months, delayed 6 months and above and unvaccinated (48 months).

RESULTS

The age-specific vaccinations assessment showed considerable delay in receipt of routine vaccination. While most (96%, 95%, 91%, 96%, 94% and 86%) children were vaccinated up-to-date for HBV3, DTaP-IPV-Hib4, PCV3, MMR/MMRV1, HAV1and HAV2 vaccine doses; only 26%, 29%, 47%, 64%, 55% and 12% were vaccinated age-appropriate. Vaccination delay was more common in vaccines with multiple doses. Vaccination delay was associated with high child's birth order, low socio-economic rank, ethnicity (delay more common in Jews vs. Arabs), season of birth (winter) and delayed receipt of DTaP-IPV-Hib vaccine 1st dose.

CONCLUSIONS

This study assessed age-appropriate childhood vaccination coverage in a national cohort of children. While the overall vaccination coverage stands in line with the WHO goals, vaccination timeliness and equity are inadequate and targeted public health intervention programs aimed at vaccination timeliness are necessary.

Research on subgroups is not research on equity attributes: Evidence from an overview of systematic reviews on vaccination

BACKGROUND

Equity remains a priority in the international health development agenda. However, major inequities in vaccination coverage jeopardise the achievement of the Sustainable Development Goals. We aim at comprehensively describing how research has addressed equity issues related to vaccination.

METHODS

We carried out an overview of systematic reviews (SRs) that explicitly explored the effects of interventions to improve vaccination in any context; for any vaccine and, in any language. We followed standard research synthesis methods to systematically search for SR, assess them for inclusion and extracting relevant data, particularly on vaccination related outcomes. To gather evidence on equity issues addressed in the SR, we used the PROGRESS-plus framework.

FINDINGS

Our search obtained 2,003 hits which resulted in 54 included SRs, published between 1994 and 2014. The quality of SRs was generally poor, with less than half complying with most of the quality criteria. Reported vaccines included, by order of frequency, influenza and Expanded Programme on Immunisation vaccines. The types of interventions more frequently reported were related to vaccination delivery strategies, financial support and information, education and communication. Most of the SRs suggested effects favouring intervention groups as opposed to comparison groups. The most frequently reported equity attribute was 'place of residence' and the least reported equity attributes were sexual orientation and religion. Very few estimates of effects actually measured differences or changes between groups having those attributes and all of them referred to the place of residence. No data was found about reducing equity gaps for vulnerable groups or minorities, or attributes such as sexual orientation, education or specific religious groups.

CONCLUSIONS

Although research on vulnerable populations as a subgroup is abundant, it fails to report on the interventions that will actually reduce inequities and consider how redistribution of health care resources could shrink the gap between the privileged and most vulnerable groups including minorities. Research, if aiming at being responsive to global health policy trends, needs to report not only on specific attributes but also on how a better redistribution of health care resources could contribute to alleviating the unjust situation of the most vulnerable populations.

Immunogenicity to poliovirus type 2 following two doses of fractional intradermal inactivated poliovirus vaccine: A novel dose sparing immunization schedule

INTRODUCTION

The polio eradication endgame strategic plan calls for the sequential removal of Sabin poliovirus serotypes from the trivalent oral poliovirus vaccine (tOPV), starting with type 2, and the introduction of ≥1 dose of inactivated poliovirus vaccine (IPV), to maintain an immunity base against poliovirus type 2. The global removal of oral poliovirus type 2 was successfully implemented in May 2016. However, IPV supply constraints has prevented introduction in 21 countries and led to complete stock-out in >20 countries.

METHODS

We conducted a literature review and contacted corresponding authors of recent studies with fractional-dose IPV (fIPV), one-fifth of intramuscular dose administered intradermally, to conduct additional type 2 immunogenicity analyses of two fIPV doses compared with one full-dose IPV.

RESULTS

Four studies were identified that assessed immunogenicity of two fIPV doses compared to one full-dose IPV. Two fractional doses are more immunogenic than 1 full-dose, with type 2 seroconversion rates improving between absolute 19-42% (median: 37%, p<0.001) and relative increase of 53-125% (median: 82%), and antibody titer to type 2 increasing by 2-32-fold (median: 10-fold). Early age of administration and shorter intervals between doses were associated with lower immunogenicity.

DISCUSSION

Overall, two fIPV doses are more immunogenic than a single full-dose, associated with significantly increased seroconversion rates and antibody titers. Two fIPV doses together use two-fifth of the vaccine compared to one full-dose IPV. In response to the current IPV shortage, a schedule of two fIPV doses at ages 6 and 14weekshas been endorsed by technical oversight committees and has been introduced in some affected countries.

Demand- and supply-side determinants of diphtheria-pertussis-tetanus nonvaccination and dropout in rural India

BACKGROUND

Although 93% of 12- to 23-month-old children in India receive at least one vaccine, typically Bacillus Calmette-Guérin, only 75% complete the recommended three doses of diphtheria-pertussis-tetanus (DPT, also referred to as DTP) vaccine. Determinants can be different for nonvaccination and dropout but have not been examined in earlier studies. We use the three-dose DPT series as a proxy for the full sequence of recommended childhood vaccines and examine the determinants of DPT nonvaccination and dropout between doses 1 and 3.

METHODS

We analyzed data on 75,728 6- to 23-month-old children in villages across India to study demand- and supply-side factors determining nonvaccination with DPT and dropout between DPT doses 1 and 3, using a multilevel approach. Data come from the District Level Household and Facility Survey 3 (2007-08).

RESULTS

Individual- and household-level factors were associated with both DPT nonvaccination and dropout between doses 1 and 3. Children whose mothers had no schooling were 2.3 times more likely not to receive any DPT vaccination and 1.5 times more likely to drop out between DPT doses 1 and 3, compared with children whose mothers had 10 or more years of schooling. Although supply-side factors related to availability of public health facilities and immunization-related health workers in villages were not correlated with dropout between DPT doses 1 and 3, children in districts where 46% or more villages had a healthcare subcentre were 1.5 times more likely to receive at least one dose of DPT vaccine compared with children in districts where 30% or fewer villages had subcentres.

CONCLUSIONS

Nonvaccination with DPT in India is influenced by village- and district-level contextual factors over and above individuals' background characteristics. Dropout between DPT doses 1 and 3 is associated more strongly with demand-side factors than with village- and district-level supply-side factors.

Immunogenicity and safety of 3-dose primary vaccination with combined DTPa-HBV-IPV/Hib in Indian infants

Multivalent combination vaccines have reduced the number of injections and therefore improved vaccine acceptance, timeliness of administration and global coverage. The hexavalent diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated poliovirus/Haemophilus influenzae type b (DTPa-HBV-IPV/Hib; Infanrix hexa™) vaccine, administered according to various schedules, is widely used for the primary vaccination of infants worldwide. In the current publication, we are presenting the immunogenicity and safety of 3 doses of DTPa-HBV-IPV/Hib vaccine when administered to Indian infants. 224 healthy infants (mean age 6.8 weeks) were vaccinated at 6-10-14 weeks (W) of age (n = 112) or 2-4-6 months (M) of age (n = 112). One month after the third vaccine dose, the seroprotection/seropositivity status against diphtheria, pertussis, tetanus, polio, hepatitis B and Hib antigens ranged from 98.6% to 100% in both groups. The vaccine response rate to the pertussis antigens ranged from 97% to 100%. Pain (6-10-14W group: 25.2%; 2-4-6M group: 13.4%) and fever (15.3% and; 15.2%, respectively) were the most frequently reported solicited local and general symptoms. Unsolicited adverse events were reported for 35.7% (6-10-14W group) and 22.3% (2-4-6M group) of subjects. No vaccine related serious adverse events were reported. In conclusion, the hexavalent DTPa-HBV-IPV/Hib vaccine was immunogenic and well tolerated, irrespective of the dosing schedule.

Vaccination coverage and factors associated with adherence to the vaccination schedule in young children of a rural area in Burkina Faso

BACKGROUND

Vaccination is an important tool for reducing infectious disease morbidity and mortality. In the past, less than 80% of children 12-23 months of age were fully immunized in Burkina Faso.

OBJECTIVES

To describe coverage and assess factors associated with adherence to the vaccination schedule in rural area Burkina Faso.

METHODS

The study population was extracted from the Nouna Health and Demographic surveillance system cohort. Data from four rounds of interviews conducted between November 2012 and June 2014 were considered. This study included 4016 children aged 12-23 months. We assessed the effects of several background factors, including sex, factors reflecting access to health care (residence, place of birth), and maternal factors (age, education, marital status), on being fully immunized defined as having received Bacillus Calmette-Guérin (BCG), three doses of diphtheria-tetanus-pertussis and oral polio vaccine, and measles vaccine by 12 months of age. The associations were studied using binomial regression to derive prevalence ratios (PRs) in univariate and multivariate regression models.

RESULTS

The full vaccination coverage increased significantly over time (72% in 2012, 79% in 2013, and 81% in 2014, p = 0.003), and the coverage was significantly lower in urban than in rural areas (PR 0.84; 0.80-0.89). Vaccination coverage was neither influenced by sex nor influenced by place of birth or by maternal factors.

CONCLUSION

The study documented a further improvement in full vaccination coverage in Burkina Faso in recent years and better vaccination coverage in rural than in urban areas. The organization of healthcare systems with systematic outreach activities in the rural areas may explain the difference between rural and urban areas.

Tetanus Immunity Gaps in Children 5-14 Years and Men ≥ 15 Years of Age Revealed by Integrated Disease Serosurveillance in Kenya, Tanzania, and Mozambique

Recent tetanus cases associated with male circumcision in Eastern and Southern Africa (ESA) prompted an examination of tetanus immunity by age and sex using multiplex serologic data from community surveys in three ESA countries during 2012-2013. Tetanus seroprotection was lower among children 5-14 years versus 1-4 years of age in Kenya (66% versus 90%) and Tanzania (66% versus 89%), but not in Mozambique (91% versus 88%), where children receive two booster doses in school. Among males ≥ 15 years of age, tetanus seroprotection was lower than females in Kenya (45% versus 96%), Tanzania (28% versus 94%), and Mozambique (64% versus 90%). Tetanus immunity from infant vaccination doses wanes over time, and only women of reproductive age routinely receive booster doses. To prevent immunity gaps in older children, adolescents, and adult men, a life-course vaccination strategy is needed to provide the three recommended tetanus booster doses.

Assessing the Evidence for Maternal Pertussis Immunization: A Report From the Bill & Melinda Gates Foundation Symposium on Pertussis Infant Disease Burden in Low- and Lower-Middle-Income Countries

Implementation of effective interventions has halved maternal and child mortality over the past 2 decades, but less progress has been made in reducing neonatal mortality. Almost 45% of under-5 global mortality now occurs in infants <1 month of age, with approximately 86% of neonatal deaths occurring in low- and lower-middle-income countries (LMICs). As an estimated 23% of neonatal deaths globally are due to infectious causes, maternal immunization (MI) is one intervention that may reduce mortality in the first few months of life, when direct protection often relies on passively transmitted maternal antibodies. Despite all countries including pertussis-containing vaccines in their routine childhood immunization schedules, supported through the Expanded Programme on Immunization, pertussis continues to circulate globally. Although based on limited robust epidemiologic data, current estimates derived from modeling implicate pertussis in 1% of under-5 mortality, with infants too young to be vaccinated at highest risk of death. Pertussis MI programs have proven effective in reducing infant pertussis mortality in high-income countries using tetanus-diphtheria-acellular pertussis (Tdap) vaccines in their maternal and infant programs; however, these vaccines are cost-prohibitive for routine use in LMICs. The reach of antenatal care programs to deliver maternal pertussis vaccines, particularly with respect to infants at greatest risk of pertussis, needs to be further evaluated. Recognizing that decisions on the potential impact of pertussis MI in LMICs need, as a first step, robust contemporary mortality data for early infant pertussis, a symposium of global key experts was held. The symposium reviewed current evidence and identified knowledge gaps with respect to the infant pertussis disease burden in LMICs, and discussed proposed strategies to assess the potential impact of pertussis MI.

Joinpoint regression analysis of pertussis crude incidence rates, Illinois, 1990-2014

Pertussis incidence has increased in recent years; we obtained incidence data from 1990-2014 from the Illinois Department of Public Health Web site. We analyzed the crude incidence rates using Joinpoint regression software. Four joinpoints were observed (2001, 2004, 2007, and 2012). Disease modeling can be used for disease control and planning by extrapolating the trend in the incidence data and applying to annual population estimates.

Vaccine strategies: Optimising outcomes

Successful immunisation programmes generally result from high vaccine effectiveness and adequate uptake of vaccines. In the development of new vaccination strategies, the structure and strength of the local healthcare system is a key consideration. In high income countries, existing infrastructures are usually used, while in less developed countries, the capacity for introducing new vaccines may need to be strengthened, particularly for vaccines administered beyond early childhood, such as the measles or human papillomavirus (HPV) vaccine. Reliable immunisation service funding is another important factor and low income countries often need external supplementary sources of finance. Many regions also obtain support in generating an evidence base for vaccination via initiatives created by organisations including World Health Organization (WHO), the Pan American Health Organization (PAHO), the Agence de Médecine Préventive and the Sabin Vaccine Institute. Strong monitoring and surveillance mechanisms are also required. An example is the efficient and low-cost approaches for measuring the impact of the hepatitis B control initiative and evaluating achievement of goals that have been established in the WHO Western Pacific region. A review of implementation strategies reveals differing degrees of success. For example, in the Americas, PAHO advanced a measles-mumps-rubella vaccine strategy, targeting different population groups in mass, catch-up and follow-up vaccination campaigns. This has had much success but coverage data from some parts of the region suggest that children are still not receiving all appropriate vaccines, highlighting problems with local service infrastructures. Stark differences in coverage levels are also observed among high income countries, as is the case with HPV vaccine implementation in the USA versus the UK and Australia, reflecting differences in delivery settings. Experience and research have shown which vaccine strategies work well and the factors that encourage success, which often include strong support from government and healthcare organisations, as well as tailored, culturally-appropriate local approaches to optimise outcomes.

Global Routine Vaccination Coverage, 2015

In 1974, the World Health Organization (WHO) established the Expanded Program on Immunization* to provide protection against six vaccine-preventable diseases through routine infant immunization (1). Based on 2015 WHO and United Nations Children's Fund (UNICEF) estimates, global coverage with the third dose of diphtheria-tetanus-pertussis vaccine (DTP3), the first dose of measles-containing vaccine (MCV1) and the third dose of polio vaccine (Pol3) has remained stable (84%-86%) since 2010. From 2014 to 2015, estimated global coverage with the second MCV dose (MCV2) increased from 39% to 43% by the end of the second year of life and from 58% to 61% when older age groups were included. Global coverage was higher in 2015 than 2010 for newer or underused vaccines, including rotavirus vaccine, pneumococcal conjugate vaccine (PCV), rubella vaccine, Haemophilus influenzae type b (Hib) vaccine, and 3 doses of hepatitis B (HepB3) vaccine. Coverage estimates varied widely by WHO Region, country, and district; in addition, for the vaccines evaluated (MCV, DTP3, Pol3, HepB3, Hib3), wide disparities were found in coverage by country income classification. Improvements in equity of access are necessary to reach and sustain higher coverage and increase protection from vaccine-preventable diseases for all persons.

Diphtheria: It is still prevalent!!!

BACKGROUND

Diphtheria is a respiratory infectious disease of childhood. It is a fatal disease and may cause complications if not recognized early and treated properly. Despite availability of effective vaccination it continues to be reported from many parts of the world particularly developing countries.

OBJECTIVE

To assess the demographic and clinical characteristics of diphtheria patients, and the predictors of outcomes of respiratory diphtheria.

METHODS

A prospective analysis of 180 patients with a clinical diagnosis of respiratory diphtheria admitted from 2011 to 2014 at a tertiary referral hospital. They were evaluated with respect to demographic details, immunization status, clinical features, complications and outcomes.

RESULTS

Most common age group affected was children less than 5 years of age (87 cases, 48.33%). The peak incidence of diphtheria was seen in the months of September and October (111 cases, 62%). Majority of the patients were unimmunized (54%), followed by partially immunized (21%). The most common complication was respiratory in 80 cases (44%), followed by cardiac complications in 54 cases (30%), and renal (16%) and neurological complications (10%). Cardiac complications were associated with the highest mortality rate (63%). The presence of bull neck and pseudomembrane score >2 was associated with a high mortality.

CONCLUSION

Diphtheria is still a preventable public health problem in many developing countries. Improved vaccination coverage, including booster dosage, coupled with early detection and effective treatment, may all reduce incidence and mortality.