Regional Vaccination Coverage Research Articles

Two decades of regional trends in vaccination completion and coverage among children aged 12-23\u2009months: an analysis of the Uganda Demographic Health Survey data from 1995 to 2016

BackgroundChildhood vaccination is an important public health intervention but there is limited information on coverage, trends, and determinants of vaccination completion in Uganda at the regional level. We examined trends in regional vaccination coverage and established the determinants of vaccination completion among children aged 12-23 months in Uganda.MethodsWe analyzed data from the women’s questionnaire for the 1995-2016 Uganda Demographic Health Survey (UDHS). Vaccine completion was defined as having received a dose of Bacillus-Calmette Guerin (BCG) vaccine; three doses of diphtheria, pertussis, and tetanus (DPT) vaccine; three doses of oral polio vaccine (OPV) (excluding OPV given at birth); and one dose of measles vaccine. We performed Chi-square tests to compare vaccination completion by socio-demographic factors stratified by 10 sub-regions: Eastern, East Central, Central 1, Central 2, Kampala, Karamoja, North, Western, West Nile, and Southwest. We performed logistic regression analysis for each of the regions to identify factors associated with vaccination completion at 5% level of statistical significance.ResultsOverall vaccination completion was 48.6% (95%CI, 47.2, 50.1) and ranged from 17.3% in Central 1 to 65.9% in Southwest. Vaccination completion rates declined significantly by 10.4% (95% confidence interval (CI), − 16.1, − 4.6) between 1995 and 2000, and increased significantly by 10.0% (95% CI, 4.6, 15.4) between 2000 and 2006, and by 5.4% (95% CI, 0.2, 10.6) between 2006 and 2011. Maternal education (secondary or higher level), receipt of tetanus toxoid (TT) during pregnancy, and possession of a child health card were associated with vaccination completion across all the sub-regions. Other factors like place of residence, religious affiliation, household wealth, maternal age, childbirth order, size of child at birth, and place of delivery were associated with vaccination completion but differed between the 10 sub-regions.ConclusionBesides considerable regional variations, the vaccination completion rate among children aged 12-23 months in Uganda remains suboptimal despite the availability of vaccines. Maternal education, receipt of TT, and possession of a child health card are associated with a higher likelihood of vaccination completion among children aged 12-23 months in all the regions of Uganda. Interventions to improve the utilization of vaccination services in Uganda should consider these factors.

Determining the burden of missed opportunities for vaccination among children admitted in healthcare facilities in India: a cross-sectional study

ObjectivesChildren accessing healthcare systems represent a vulnerable population with risk factors for poor health outcomes, including vaccine-preventable diseases. We aimed to quantify missed vaccination opportunities among hospitalised children in India,...

Vaccine stockouts and vaccination rate: examination of unique administrative data from Nigeria.

Universal access to vaccines is crucial in protecting the population from deadly diseases. This study presents the prevalence of vaccine stockouts in Nigeria and examines the correlation between the vaccine stockouts and vaccine take-up. We use the unique administrative data of monthly vaccine stockouts at each health facility in Nigeria. To evaluate the correlation between the stockouts and the vaccine take-up, the administrative data were merged with the Nigeria Demographic and Health Survey conducted in 2013. We used logistic regression for the correlational study. The prevalence of vaccine stockouts in Nigeria is high: 82.7% between 2012 and 2013. We find a negative correlation between vaccine stockouts and vaccine take-up. However, we observe the differential correlational pattern depending on the regional vaccine coverage, which we consider as the proxy of the level of demand for vaccines. We find that, while vaccine stockouts are correlated with the low vaccine take-up on average, this negative correlation between stockouts and vaccination rate is observed only in regions with low demand for vaccines. Reducing vaccine stockouts in regions with the low vaccination coverage might be an effective way to increase the overall vaccination rate.

Spatially Heterogeneous Vaccine Coverage and Externalities in a Computational Model of Epidemics

We develop an agent-based computational model of epidemics with varying amounts of heterogeneity in regional vaccination coverage. We examine the severity of the resulting epidemics and the externalities created between high and low vaccination regions. The resulting size of the epidemics depends upon the heterogeneity of coverage, the interaction structure in the population, and how close the population is to herd immunity. Holding overall vaccination levels constant, the mean epidemic size increases and a larger level of vaccinations is needed to reach herd immunity when there is greater variability in the regional vaccination rates as long as the vaccination level is sufficiently high. This relationship amplifies when the contacts of individuals in the model have a greater share of inter-regional linkages. However, when inter-regional linkages and vaccination levels are sufficiently low, the mean epidemic size can decrease when there is greater variability in the regional vaccination rates. Further, we find that the magnitude of externalities between regions with different levels of vaccine coverage depends crucially on how close the population is to herd immunity. If population level vaccination coverage is sufficiently high (low) shifting connections from low coverage regions to high coverage regions will decrease (increase) mean epidemic size.

Association of Pneumococcal Conjugate Vaccine Coverage With Pneumococcal Meningitis: An Analysis of French Administrative Areas, 2001-2016.

Geographic variations of invasive pneumococcal disease incidence and serotype distributions were observed after pneumococcal conjugate vaccine introduction at regional levels and among French administrative areas. The variations could be related to regional vaccine coverage (VC) variations that might have direct consequences for vaccination-policy impact on invasive pneumococcal disease, particularly pneumococcal meningitis (PM) incidence. We assessed vaccine impact from 2001 to 2016 in France by estimating the contribution of regional VC differences to variations of annual local PM incidence. Using a mixed-effect Poisson model, we showed that, despite some variations of VC among administrative areas, vaccine impact on vaccine-serotype PM was homogeneously confirmed among administrative areas. Compared with the prevaccine era, the cumulative VC impact on vaccine serotypes led, in 2016, to PM reductions ranging among regions from 87% (25th percentile) to 91% (75th percentile) for 7-valent pneumococcal conjugate vaccine serotypes and from 58% to 63% for the 6 additional 13-valent pneumococcal conjugate vaccine serotypes. Nonvaccine-serotype PM increases from the prevaccine era ranged among areas from 98% to 127%. By taking into account the cumulative impact of growing VC and VC differences, our analyses confirmed high vaccine impact on vaccine-serotype PM case rates and suggest that VC variations cannot explain PM administrative area differences.

Poliovirus immunity among children under five years-old in accessible areas of Afghanistan, 2013

BackgroundAfghanistan remains among the three countries with endemic wild poliovirus transmission, and high population immunity levels are required to interrupt transmission and prevent outbreaks. Surveillance and vaccination of children in Afghanistan have been challenging due to security issues limiting accessibility in certain areas. MethodsA serosurvey was conducted in 2013 within accessible enumeration areas (EAs) among children aged <5 years using samples collected for a national micronutrient assessment survey to assess poliovirus immunity in Afghanistan. Of 21194 total EAs in Afghanistan, 107 were inaccessible and therefore were excluded from the sampling frame. ResultsPopulation immunity was high overall but varied for the poliovirus serotypes, and was lowest for type 3 (95% [95% CI: 93%, 96%]) compared to type 1 (99% [95% CI:97%, 99%]) and type 2 (98% [95% CI:96%, 99%]). The proportion of the population immune to all three types was 93% (95% CI: 91%, 95%), and the proportion seronegative for all three types was 0.5% (95% CI: 0.2%, 1.7%). ConclusionExcept for regional differences in immunity to type 3 virus, there were no other apparent differences in seroprevalence by region or by any of the demographic or nutritional characteristics assessed in this study. The study was not powered to provide provincial level seroprevalence estimates, but Paktika Province, in the South region, had the largest proportion of seronegative specimens for type 1 (4 seronegative of 17 serum specimens compared to 14 seronegative of 673 for the remainder of the areas). Among accessible children in Afghanistan, seroprevalence of antibodies to poliovirus was high, with most seroprevalence reported at 95% or greater. Despite high seroprevalence in areas assessed in this study, the continued detection of poliovirus cases in the South and East regions indicate that overall regional vaccination coverage and performance is not sufficient to stop polio transmission.

Relationship between Vaccine Stockouts and Vaccination Rate: Examination of Unique Administrative Data from Nigeria

Background: Universal access to vaccines is crucial in protecting the population from deadly diseases. This study presents the prevalence of vaccine stockouts in Nigeria and examines the correlation between the vaccine stockouts and vaccine take-up. Methods: We use the unique administrative data of monthly vaccine stockouts at each health facility in Nigeria. To evaluate the correlation between the stockouts and the vaccine take-up, the administrative data was merged to Nigeria Demographic and Health Survey conducted in 2013. We used the logistic regression for the correlational study. Results: The prevalence of vaccine stockouts in Nigeria is high: 82.7 percent between 2012 and 2013. We find the negative correlation between vaccine stockouts and the vaccine take-up. However, we observe the differential correlational pattern depending on the regional vaccine coverage, which we consider as the proxy of the level of demand for vaccines. Conclusion: We find that, while vaccine stockouts is correlated with the low vaccine take-up on average, the high stockouts is also attributed to the high vaccination coverage in regions with high demand for vaccines. To increase the vaccination rate, it is the most effective to strengthen the health system to reduce vaccine stockouts in regions with the low vaccination coverage.

Vaccination Coverage Among Children Aged 2 Years - U.S. Affiliated Pacific Islands, April-October, 2016.

Vaccine-preventable diseases (VPDs) cause substantial morbidity and mortality in the United States Affiliated Pacific Islands (USAPI).* CDC collaborates with USAPI immunization programs to monitor vaccination coverage. In 2016, † USAPI immunization programs and CDC piloted a method for estimating up-to-date status among children aged 2 years using medical record abstraction to ascertain regional vaccination coverage. This was the first concurrent assessment of childhood vaccination coverage across five USAPI jurisdictions (American Samoa; Chuuk State, Federated States of Micronesia [FSM]; Commonwealth of the Northern Mariana Islands [CNMI]; Republic of the Marshall Islands [RMI]; and Republic of Palau).§ Differences in vaccination coverage between main and outer islands¶ were assessed for two jurisdictions where data were adequate.** Series coverage in this report includes the following doses of vaccines: ≥4 doses of diphtheria and tetanus toxoids and acellular pertussis vaccine (DTaP); ≥3 doses of inactivated poliovirus vaccine (IPV); ≥1 dose of measles, mumps, and rubella vaccine (MMR); ≥3 doses of Haemophilus influenzae type B (Hib) vaccine; ≥3 doses of hepatitis B (HepB) vaccine; and ≥4 doses of pneumococcal conjugate vaccine (PCV); i.e., 4:3:1:3:3:4. Coverage with ≥3 doses of rotavirus vaccine was also assessed. Completion of the recommended series of each of these vaccines†† was <90% in all jurisdictions except Palau. Coverage with the full recommended six-vaccine series (4:3:1:3:3:4) ranged from 19.5% (Chuuk) to 69.1% (Palau). In RMI and Chuuk, coverage was lower in the outer islands than in the main islands for most vaccines, with differences ranging from 0.9 to 66.8 percentage points. Medical record abstraction enabled rapid vaccination coverage assessment and timely dissemination of results to guide programmatic decision-making. Effectively monitoring vaccination coverage, coupled with implementation of data-driven interventions, is essential to maintain protection from VPD outbreaks in the region and the mainland United States.

Challenges of maintaining polio-free status of the European Region.

The European region, certified as polio free in 2002, had recent wild poliovirus (WPV) introductions, resulting in a major outbreak in Central Asian countries and Russia in 2010 and in current widespread WPV type 1 circulation in Israel, which endangered the polio-free status of the region. We assessed the data on the major determinants of poliovirus transmission risk (population immunity, surveillance, and outbreak preparedness) and reviewed current threats and measures implemented in response to recent WPV introductions. Despite high regional vaccination coverage and functioning surveillance, several countries in the region are at high or intermediate risk of poliovirus transmission. Coverage remains suboptimal in some countries, subnational geographic areas, and population groups, and surveillance (acute flaccid paralysis, enterovirus, and environmental) needs further strengthening. Supplementary immunization activities, which were instrumental in the rapid interruption of WPV1 circulation in 2010, should be implemented in high-risk countries to close population immunity gaps. National polio outbreak preparedness plans need strengthening. Immunization efforts to interrupt WPV transmission in Israel should continue. The European region has successfully maintained its polio-free status since 2002, but numerous challenges remain. Staying polio free will require continued coordinated efforts, political commitment and financial support from all countries.

Cervical intraepithelial neoplasia grade 2 or worse in Galicia, Spain: HPV 16 prevalence and vaccination impact

IntroductionThe etiology of cervical intraepithelial neoplasia grade 2 or worse (CIN2+) can influence the efficacy of Public Health preventive strategies. This study aimed to determine the high-risk papillomavirus (HR-HPV) prevalence in CIN2+ cases in unvaccinated women in Galicia (Spain), the expected impact of bivalent vaccination, and the distribution of HPV 16 in squamous lesions. Material and methodsNinety-four histologically confirmed cases of CIN2+ (2009–2010) were retrospectively studied: 23 CIN2, 58 CIN3− squamous carcinoma in situ (CIN3-CIS), 5 adenocarcinoma in situ (AIS), and 8 invasive squamous cervical cancer (SCC). Linear Array HPV Genotyping Test (Roche Diagnostics, Mannheim, Germany) was performed on the cervical specimens. Bivalent vaccination impact was calculated, based on regional vaccination coverage data, local HR-HPV prevalence, and reported efficacy (direct and cross-protection) of the vaccine. ResultsHR-HPV prevalence was 96.8%. The most frequent genotypes were HPV 16 (48.8–58.2%) and HPV 31 (9.3%–12.1%), considering single infections or single-multiple infections, respectively (hierarchical attribution). In squamous lesions, HPV 16 prevalence in women younger than 45 years of age increased in severe lesions (CIN3-CIS/SCC, OR 4.2), and was higher than in older women (OR 5.5). The vaccine could reduce the cumulative incidence of CIN2+ by 50.6% (direct protection), or by 62.7% (direct and cross-protection). ConclusionHPV vaccination could have a great impact in women younger than 45 years of age due to the high prevalence of HPV 16 in their lesions.

Effect of Rotavirus Vaccine on Diarrhea Mortality in Different Socioeconomic Regions of Mexico

In Mexico, declines in childhood diarrhea deaths have been documented during 2008-2010 after rotavirus vaccine introduction in 2007. Because of concerns about variation in rotavirus vaccine efficacy by socioeconomic status, we compared reductions in diarrhea mortality in the lesser developed southern region versus the more developed northern and central regions of Mexico. We obtained data from national vital statistics on diarrhea deaths among children aged <5 years from 2002 through 2011. We compared region-specific diarrhea mortality before (2003-2006) and after (2009-2011) vaccine introduction. Regional vaccine coverage was estimated from administrative data, and socioeconomic status was assessed by using the Human Development Index. In northern, central, and southern Mexico, the 2007 Human Development Index was 0.84, 0.82, and 0.77, respectively, and by 2010 an estimated 99%, 84%, and 89% of children aged <12 months had completed rotavirus vaccination. Diarrhea mortality among children <5 years old declined from 8.3, 17.9, and 28.5 deaths per 100,000 children during 2003-2006 to 4.5, 8.1, and 16.2 in 2009-2011 in northern, central, and southern Mexico, respectively, corresponding to rate reductions of 45%, 55%, and 43%. No significant differences were observed in rate reductions between regions (P > .8). After introduction of rotavirus vaccination, marked and sustained declines in diarrhea deaths were seen among children in all regions of Mexico, including in the least developed southern region with the highest baseline diarrhea mortality. This finding indicates equitable vaccine delivery to children with varying risk of mortality and reaffirms the beneficial effects of rotavirus vaccination against fatal diarrheal disease.

Prevention of invasive diseases: strategies to increase vaccination coverage in children and adolescents.

Vaccines able to prevent invasive bacterial diseases have been introduced into national and/or regional immunization plans through different strategies. We evaluated Haemophilus influenzae type b, Pneumococcus and Meningococcus C vaccination coverage in the 5 Ligurian Local Health Agencies, in the Liguria Region, and in Italy in order to assess the efficacy of current immunisation policies concerning children at the 24th month and adolescents. Furthermore, we considered new strategies for increasing vaccination coverage. We estimated the vaccination coverage of Local Health Agency 4 by means of the "OASIS" software. The regional mean vaccination coverage was calculated from the data provided by the other four Local Health Agencies in Liguria. National data were obtained from the database of the Ministry of Health and from the last report of the ICONA Working Group. We used a questionnaire to evaluate the knowledge of Meningococcus C vaccination among the pediatricians and general practitioners operating in our Local Health Agency. The regional vaccination coverage at the 24th month proved to be: > 95% for Haemophilus influenzae type b, 93% for Pneumococcus and 87% for Meningococcus C. The national mean is: > 95% for Haemophilus influenza type b, 55% for Pneumococcus and 37% for Meningococcus C. Meningococcus C vaccination coverage among adolescents is 49% in Liguria, while the national mean is 16%. The questionnaire administered to the physicians was composed of 5 questions, which were answered by 81% of pediatricians and only 22% of general practitioners. Reducing the incidence of invasive meningococcal diseases through large-scale vaccination was deemed very important by 92% of pediatricians and 81% of general practitioners. About 92% of pediatricians and 85% of general practitioners considered the vaccine safe and effective. All (100%) physicians expressed their agreement with the Ligurian immunization strategy. However, while all the pediatricians reported recommending this vaccination, only 76% of general practitioners did so. Finally, all the physicians interviewed stated their willingness to collaborate with the Department of Prevention to increase vaccination coverage. VC against Hib at the 24th month, in both Liguria and Italy, proved excellent. Compliance with vaccination against Pneumococcus has been very high since its introduction in 2003 in Liguria, while the national mean is suboptimal. The regional vaccination coverage against Meningococcus C at the 24th month is good; the national value, however, is low because some Italian Regions have not yet introduced this vaccination into their immunization plans. Vaccination coverage in adolescents varies widely among the Ligurian Local Health Agencies and needs to be increased; the national figure is very low because few Regions have introduced this vaccination. However, achieving compliance with vaccinations in adolescents is difficult. The questionnaire indicated that general practitioners place less emphasis on vaccinations than pediatricians. Nevertheless, both general practitioners and pediatricians expressed their willingness to collaborate with the Department of Prevention of Local Health Agency 4 in improving the immunization strategies aimed at adolescents. In conclusion, we consider it very important to create a network involving the Department of Prevention, pediatricians and general practitioners, in order to share the best immunization strategies.

The Americas: Paving the Road Toward Global Measles Eradication

The Region of the Americas set a goal of interrupting endemic measles virus transmission by the end of 2000. This decision was primarily based on rapid decreases in measles disease burden in pioneering countries that implemented Pan American Health Organization-recommended vaccination and surveillance strategies. Review of these strategies may inform measles elimination efforts in other regions. Results from the implementation of the measles elimination strategy in the Americas were compiled and analyzed over a 30-year period, which was divided into 4 phases: the early years of the Expanded Program on Immunization (1980-1986); the start-up phase for elimination (1987-1994); the elimination phase (1995-2002); and the postelimination phase (2003-2010). Factors that contributed to elimination and the challenges confronted during the postelimination phase are discussed. An analysis of vaccination strategies over time highlights the transition from monovalent measles vaccine to the incorporation of measles-mumps-rubella vaccine administered in the routine program. Regional vaccination coverage increased during the period 1987-2010, sustained at ≥90% since 1998. Measles elimination efforts led to the implementation of 157 national vaccination campaigns, vaccinating a total of 440 million persons. Endemic measles virus transmission was interrupted in 2002. After elimination, measles importations and associated outbreaks occurred. Measles incidence has remained at <1 case per 1 million population since 2002. The success of measles elimination strategies in the Americas suggests that global measles eradication is attainable.

Spatial analysis of bluetongue cases and vaccination of Swiss cattle in 2008 and 2009

Bluetongue (BT) is a vector-borne viral disease of ruminants. The infection is widespread globally with major implications for international animal trade and production. In 2006, BT virus serotype 8 (BTV-8) was encountered in Europe for the first time, causing extensive production losses and death in susceptible livestock. Following the appearance of BTV-8 in Switzerland in 2007, a compulsory vaccination programme was launched in the subsequent year. Due to social factors and difficulties to reach animals on high pasture, the regional vaccination coverage varied across the country in both 2008 and 2009. In this study, the effect of vaccination on the spatial occurrence of BTV-8 and the associated relative disease risk in Switzerland in 2008 and 2009 were investigated by a spatial Bayesian hierarchical approach. Bayesian posterior distributions were obtained by integrated nested Laplace approximations, a promising alternative to commonly used Markov chain Monte Carlo methods. The number of observed BTV-8 outbreaks in Switzerland decreased notably from 2008 to 2009. However, only a non-significant association between vaccination coverage and the probability of a spatial unit being infected with BTV-8 was identified using the model developed for this study. The relative disease risk varied significantly across the country, with a higher relative risk of BTV-8 infection in western and north-western Switzerland where environmental conditions are more suitable for vector presence and viral transmission. Examination of the spatial correlation between disease occurrence, control measures and associated ecological factors can be valuable in the evaluation and development of disease control programmes, allowing prioritisation of areas with a high relative risk of disease.

Une campagne pilote de promotion de la vaccination : description et premiers résultats d'un programme régional

Context and objective In 2003, the Franche-Comté decided to launch an innovating program, with the support of many national partners. The objective was to improve the vaccine coverage of Franche-Comté population. Description of the intervention It consisted in organizing every year (for three years) a week of vaccination with the active assistance of community healthcare professionals (doctors, pharmacists, etc.) and to develop complementary activities during the year: media campaign, visits to all local physicians, training, written data (posters, booklets, etc.), implementing an exhibition. Results This program is not yet finished. However, the first results (after two years) are very encouraging. Several types of evaluation were carried out: 1) Process: inquiry with physicians; 2) Impact: follow-up of vaccine refunding evolution. The notoriety of the program seems important with physicians. They declared having changed their vaccination behavior with their patients. After the vaccination week, the number of vaccines refunded in the next 2 months (compared to the same reference period in 2003) increased by 10% in 2005, after a first increase of 5% in 2004. Discussion/Conclusion The initial analysis confirms that the impact of "a vaccination week" seems to reinforce regional vaccine coverage. Moreover, WHO Europe and the French Health Ministry have decided to extend this program to the national level in 2007.

STATE OF IMMUNIZATION IN THE AMERICAS

Countries in the Americas have led the world in conquering infectious diseases preventable through vaccination. In 1971, the Western hemisphere achieved smallpox eradication. In 1991, the Americas were free of indigenous transmission of wild poliovirus. In 1998, overall regional vaccination coverage was 86% for diphtheria-pertussis-tetanus, 89% for oral poliovirus vaccine 3, 98% for bacille Calmette-Guérin vaccine, and 85% for measles. These figures confirm that most of the children in the Americas are protected against these diseases. The breakthroughs obtained in immunization have stimulated countries to promote new initiatives aimed at the control and eradication of other vaccine-preventable diseases and to introduce new vaccines into routine schedules. In the 21st century, vaccines will remain the most cost-effective means of preventing diseases and avoiding expensive treatment costs.