VoICE : Search Immunization Evidence

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The VoICE tool is a compendium of the many direct and downstream impacts of vaccine-preventable disease and immunization. The database contains summary explanations of the link between immunization and each impact, as well as sources of evidence for each link. You can browse the VoICE tool by topic, or use the filters to find results based on topic, disease or vaccine, location and published year.

85 Key Concepts, 78 Sources
Key Concept

Key Evidence: In a Southwest state of Nigeria, children in the poorest category (quintile) of households were 14 times more likely to be partially immunized or not immunized, and those in the next poorest category were eight times more likely to be partially immunized or not immunized than children in the wealthiest group, after adjusting for factors such as education, religion, and ethnicity.

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Key Concept

Key Evidence: The introduction of PCV-10, along with a “catch-up” campaign for 1-4 year olds, led to dramatic reductions in the rates of pneumococcal pneumonia in adults (≥18 years old) in a rural area of Kenya with high rates of both adult pneumococcal pneumonia and HIV. Over five years following the vaccine introduction, the incidence rates among adults were 47-94% lower each year than in the pre-vaccine period, with similar declines for HIV-infected and HIV-uninfected adults.

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Key Concept

Key Evidence: A study in Kenya estimated that the failure to vaccinate the 21% of children considered hard-to-reach (living beyond a 5 km radius of a vaccination post) against measles would result — over 4 years — in more than 1,400 measles cases, 257 deaths, and cost nearly US$10 million, mainly in productivity losses from caretakers missing work.

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Key Concept

Key Evidence: An outreach strategy in Kenya to vaccinate children against measles in hard-to-reach areas (e.g., beyond 5 km from a vaccination post) would be highly cost-effective, despite the higher cost per child to reach these children. The estimated cost per DALY averted ranged from US$122 (if 50% of these children receive the first dose and one-half of them the second dose) to US$274 (if 100% receive the first dose) — considerably less than the country’s GDP per capita of US$1,865 used as the threshold of cost-effectiveness.

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Key Concept

Key Evidence: In an effort to reach children with vitamin A deficiency in the African countries of Angola, Chad, Cote d’Ivoire, and Togo, vitamin A supplementation was administered during Polio vaccine campaigns. This led to a minimum coverage of 80% for vitamin A and 84% for polio vaccine in all of the immunization campaigns. During the second year of vitamin A integration into the polio vaccination campaign, coverage exceeded 90% for both vitamin A and polio vaccination in all four countries.

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Key Concept

Key Evidence: The expertise and assets gained through efforts to eradicate polio at least partially explain the improvement between 2013 and 2015 in vaccination coverage of DPT3 in six out of ten “focus” countries of the Polio Eradication Endgame strategic plan. This includes substantial increases in vaccination rates in India, Nigeria, and Ethiopia, which, combined, reduced the number of children not fully vaccinated with DPT by 2 million in 2 years.

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Key Concept

Key Evidence: A study of over 80,000 children in Kenya designed to understand the role of inadequate health systems on childhood survival beyond 59 months of age showed that a higher per capita density of heath facilities resulted in a 25% reduction in the risk of death. However, user fees for sick-child visits increased the risk of death by 30%.

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Key Concept

Key Evidence: The 2008 Nigerian Demographic Health Survey data suggest that children in communities with high unemployment were 1/3 as likely to be fully immunized than children in communities with a medium level of unemployment.

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Key Concept

Key Evidence: The 2008 Nigerian Demographic Health Survey data suggest that children in communities with high unemployment were 1/3 as likely to be fully immunized than children in communities with a medium level of unemployment.

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Key Evidence: Children of divorced mothers were three times less likely to be fully immunized than mothers cohabitating with a partner. In addition, it was found that children of mothers who work part time were approximately 2.3 times less likely to be fully immunized than mothers who work full time.

From the VoICE Editors: This study, conducted in Ghana, used Chi-Squared analysis to determine adjusted odds ratios. Multivariable analysis was not conducted.

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Key Concept

Key Evidence: According to a systematic review and meta-analysis, children who are rural-urban migrants in China, India and Nigeria were less likely to be fully-immunized by the age of one year than non-migrant urban residents and the general population. These inequities in vaccination rates — often concealed in national averages — call for special efforts to improve immunization rates in this rapidly growing sub-population to reduce both health inequities and the risk of infectious disease outbreaks in the wider society.

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Key Concept

Key Evidence: Full immunization coverage, within the Democratic Republic of Congo, varies drastically by region. In the province with the lowest coverage, approximately 5% of children were fully immunized, while in the province with highest coverage, over 70% of children were fully immunized.

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Key Concept

Key Evidence: A 2006-07 meningococcal meningitis epidemic in Burkina Faso cost households an average of US$90 for each case of meningitis that occurred. These costs — representing nearly 2.5 months of the average per capita income for that year — included direct and indirect costs of treatment and lost income to caretakers.

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Key Concept

Key Evidence: Communities with higher rates of health services utilization, particularly institutional childbirth, were more likely to have higher immunization coverage rates.

From the VoICE editors: This data, from a study in the Democratic Republic of Congo, had an adjusted odds ratio of 2.36.

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Key Evidence: Missed opportunities for vaccination i.e. percentage of children who failed to attain full immunization coverage (FIC) among those receiving one or more other health interventions were assessed through a study of 14 geographically diverse countries. In children with a vaccination rate below 70%, FIC was observed to be lowest in children born to mothers who failed to attend antenatal care across countries. The largest difference in FIC (54%) was observed in Côte d’Ivoire comparing children born to mothers who attended four or more ANC visits compared to no ANC visits. The presence of skilled birth attendant (SBA) was linked to higher rates of FIC with a 36% lower FIC in children born without a SBA in Nigeria. Post-natal care (PNC) acted as a factor contributing to 31% increase in FIC in the children who received PNC in Ethiopia. Vitamin A supplementation and sleeping under an insecticide treated bed net (ITN) were also positively linked to increase in FIC in the Democratic Republic of Congo and Haiti respectively.

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Key Concept

Key Evidence: A pooled analysis of nine studies assessing the effects of diarrhea on stunting prior to the age of 24 months showed that the odds of stunting were significantly increased with each diarrheal episode. Each day of diarrhea prior to attaining 24 months of age also contributed to the risk of stunting. For each five episodes of diarrhea, the odds of stunting increased by 13%. In addition, once a child becomes stunted, only 6% of those stunted at 6 months of age recovered by 24 months of age.

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Key Concept

Key Evidence: Findings of a systematic review evaluating the relationship between pneumonia and malnourishment found that severely malnourished children in developing countries had 2.5 to 15 times the risk of death. For children with moderate malnutrition, the risk of death ranged from 1.2 to 36.

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Key Concept

Key Evidence: In urban residents in the Democratic Republic of Congo, chronically malnourished children were less likely to have received two doses of measles-containing vaccine compared to healthy children.

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Key Concept

Key Evidence: Using data on the spread of Ebola from person to person during historical Ebola outbreaks to compare vaccination strategies, researchers found that prophylatically vaccinating all healthcare workers would have decreased the number of disease cases in the 2014 epidemics in Guinea and Nigeria by 60-80%.

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Key Concept

Key Evidence: Children in Tanzania living 5 km or greater distance from the nearest healthcare facility were less likely to be immunized than children living less than 5 km from facilities. Compared to children living close a health facility, children far from a health facility had almost three times the risk of missing out on BCG, 84% higher risk of missing the third dose of DTP, and 48% higher risk of missing the first dose of measles-containing vaccine. Of children who did receive BCG, those living more than 5 km from facilities were 26% more likely to received BCG vaccine late than children close to the facility.

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Key Concept

Key Evidence: In Tanzania, poverty was found to have a negative effect on receiving vaccines on time (at the recommended age). Children in the wealthiest quintile experienced 19% fewer delays for BCG vaccination, 23% fewer delays for the third dose of DTP vaccination, and 31% fewer delays for the first dose of measles-containing vaccine compared to children of the poorest quintile.

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Key Concept

Key Evidence: An analysis of the association between undernutrition and mortality in young children revealed that in 60% of deaths due to diarrhea, 52% of deaths due to pneumonia, 45% of deaths due to measles and 57% of deaths attributable to malaria, undernutrition was a contributing factor.

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Key Concept

Key Evidence: An analysis of the impact of rotavirus vaccine in 25 countries found that the rates of vaccination in all countries were highest and risk mortality lowest in the top two wealth quintile’s coverage. Countries differed in the relative inequities in these two underlying variables. Cost per DALYs averted in substantially greater in the higher quintiles. In all countries, the greatest potential vaccine benefit was in the poorest quintiles; however, reduced vaccination coverage lowered the projected vaccine benefit.

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Key Evidence: A study looking at the impact of pneumococcal vaccine introduction and scaling up pneumonia treatment in Ethiopia found that 30-40% of all deaths averted by these interventions would be expected to occur in the poorest wealth quintile. The greatest resulting financial risk protection would also be concentrated among the bottom income quintile.

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Key Concept

Key Evidence: In a systematic review of qualitative research from low- and middle-income countries, women’s low social status was shown to be a barrier to their children accessing vaccinations. Specific barriers included access to education, income, resource allocation, and autonomous decision-making related to time. The authors suggest that expanding the responsibility for children’s health to both parents (mothers and fathers) may be one important element in removing persistent barriers to immunization often faced by mothers.

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Key Concept

Key Evidence: A large meningococcal meningitis epidemic in Burkina Faso cost the health system an estimated US$7.1 million, representing nearly 2% of the country’s entire annual health budget.

From the VoICE editors: In this study of a 2007 outbreak, 86% of the health system cost covered a reactive vaccination campaign using older polysaccharide vaccines. Routine vaccination with new, conjugate vaccines are expected to prevent or limit future outbreaks and thus reduce these costs.

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Key Evidence: In a comprehensive accounting of the costs of the 2014 Ebola outbreak in West Africa, Huber et al. estimate the economic and social costs to have been US$53 billion, of which US$18.8 billion was attributed to non-Ebola deaths.

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Key Concept

Key Evidence: Across many South Asian and sub-Saharan African countries, children of mothers who received no formal education were nearly 3 times as likely to die before reaching age 5 as those born to mothers with some secondary education.

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Key Concept

Key Evidence: In contrast to non-Somalis, family wealth did not significantly affect the likelihood of being fully vaccinated among Somali refugee children living in Kenya. This may point to systemic barriers to vaccination that cut across all socio-economic levels of the Somali refugee population.

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Key Concept

Key Evidence: Meningococcal meningitis epidemics in Burkina Faso “… disrupted all health services from national to operational levels,…” according to a 2011 study. Impacts included a shortage of available hospital beds and medicines, a reduction or delay in routine lab analyses for other diseases, longer wait times, and an increase in misdiagnoses by overtaxed health workers.

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Key Evidence: Fear of Ebola during the 2014-2016 epidemic in 3 West African countries had a major impact on the health sector in neighboring Nigeria, where hospitals reported sharp decreases in patient volume resulting in major financial losses. Some hospitals also turned away febrile patients to prevent being associated with Ebola while staff in other hospitals abandoned their posts.

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Key Evidence: A 2015 study projected that the crippling of immunization programs resulting from the 2014 Ebola epidemic in Guinea, Liberia, and Sierra Leone could double the number of people at risk of a measles outbreak, and could cause up to 16,000 measles deaths, surpassing the number of deaths caused by Ebola itself.

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Key Concept

Key Evidence: Kenyan children born outside of a health facility with the aid of a traditional birth attendant were around 80% more likely to be non-vaccinated or under-vaccinated than children born in a government health facility.

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Key Evidence: Use of recommended maternal health care services — defined as at least 4 antenatal care visits, having a skilled attendant at birth, and delivery in a health facility — was a predictor of timely vaccination of mothers’ infants in a study conducted in Ghana. Compared to children whose mothers received one or two of these services, infants born to mothers who received all three interventions were roughly 30% more likely to be fully vaccinated by 12-23 months of age, while children whose mothers received none of these services were only about half as likely to be fully vaccinated. Investing in maternal health, which creates familiarity with the health system and increases mothers’ knowledge about disease prevention, can improve the health of both the mother and her children beyond infancy.

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Key Evidence: Ethiopian mothers use of any of three maternal health services — antenatal care, delivery services, or tetanus vaccination — significantly increased the likelihood of their children being fully immunized by 12-23 months of age. Therefore, national immunization initiatives should concentrate on improving access of pregnant women to these key maternal health services.

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Key Concept

Key Evidence: The first study of the cost-effectiveness of typhoid conjugate vaccines found that routinely immunizing infants at 9 months of age would actually save costs in 2 settings (Delhi, India and a rural area of Vietnam), due to high incidence or high hospitalization rates, and would be cost-effective in the study’s 3 other sites (in India and Kenya). Adding a one-time catch-up campaign for various older age groups would still save costs in the Delhi and Vietnam, and increase the cost-effectiveness in the others, making it economically justifiable.

From the VoICE Editors: The study incorporated herd effects into its model, looked only at the perspective of healthcare payers and assumed the use of a single dose vaccine at 1 international dollar.

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Key Concept

Key Evidence: Providing a birth dose of hepatitis B vaccine to all newborns (in addition to routine HepB immunization) was found to be a highly cost-effective means of preventing hepatitis B-related deaths in three refugee populations in Africa which are at extremely high risk of hepatitis B infection. Providing a birth dose only to newborns whose mothers test positive on a rapid diagnostic test was less cost-effective than vaccinating all newborns automatically. Thus, universal hepatitis B vaccination of newborns should remain a priority in refugee camps, despite competing humanitarian needs.

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Key Evidence: Children living in the Yida refugee camp in South Sudan in 2013 were found to have an elevated rate of pneumonia infections likely due to malnutrition, overcrowding, and inadequate shelter. Using these data, the CDC estimated that the use of Hib and pneumococcal vaccines in children under 2 years of age in the camp would be cost-effective under all dosing scenarios evaluated. Medecines Sans Frontiers (MSF) provided medical services to this refugee camp and found delivery of these vaccines to be feasible and effective in this setting.

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Key Evidence: A comprehensive review of the economics of cholera and cholera prevention concluded that vaccination using oral cholera vaccines can be cost-effective, especially when herd effects are taken into account and when vaccination is administered to populations and age groups with high incidence rates (e.g., children) and to areas with high cholera case fatality rates.

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Key Concept

Key Evidence: Somali refugee children in Kenya were nearly 60 times more likely than children of the main ethnic group in the study (Kikuyu) to not have received any childhood immunization and more than twice as likely to have not completed their vaccinations. Although Somali children made up less than 8% of the sample, they accounted for nearly half of all non-vaccinated children.

From the VoICE Editors: This study used data from Kenya’s Demographic and Health Survey data.

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Key Concept

Key Evidence: Somali refugee children in Kenya were nearly 60 times more likely than children of the main ethnic group in the study (Kikuyu) to not have received any childhood immunization and more than twice as likely to have not completed their vaccinations. Although Somali children made up less than 8% of the sample, they accounted for nearly half of all non-vaccinated children.

From the VoICE Editors: This study used data from Kenya’s Demographic and Health Survey data.

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Key Concept

Key Evidence: An analysis conducted in areas of Ethiopia with high proportions of refugees found that high measles vaccination coverage was linked to lower rates of acute malnutrition (wasting) in children under five. For each percentage point increase in measles vaccination coverage, there was a 0.65% decrease in the rate of acute malnutrition in these areas.

From the VoICE Editors: The analysis was conducted on data from more than 150 nutrition surveys.

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Key Concept

Key Evidence: An analysis conducted in areas of Ethiopia with high proportions of refugees found that high measles vaccination coverage was linked to lower rates of acute malnutrition (wasting) in children under five. For each percentage point increase in measles vaccination coverage, there was a 0.65% decrease in the rate of acute malnutrition in these areas.

From the VoICE Editors: The analysis was conducted on data from more than 150 nutrition surveys.

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Key Concept

Key Evidence: Adding a birth dose of hepatitis B vaccine to routine immunization of refugees in Africa — who have particularly high infection rates — is a highly cost-effective means of reducing transmission of the infection thus strengthening the overall global health security among these mobile, vulnerable populations.

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Key Concept

Key Evidence: A study modeling the relationship between disease and poverty in Ethiopia found that among the top 20 causes of death in Ethiopia, diarrhea and lower respiratory infections (LRIs) are the top two drivers of medical impoverishment. It is estimated that in 2013, out-of-pocket direct medical costs for diarrheal disease drove an estimated 164,000 households below the poverty line (representing 47% of all the diarrhea cases), and LRIs led to an estimated 59,000 cases of poverty (17% of LRI cases). Of the top 10 health-associated drivers of poverty, four are at least partially vaccine-preventable (1. Diarrhea, 2. LRI, 4. TB. 10. Pertussis).

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Key Concept

Key Evidence: A 2019 analysis of survey data from India, Ethiopia and Vietnam found that children vaccinated against measles scored better on cognitive tests of language development, math and reading than children who did not receive measles vaccines.

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Key Concept

Key Evidence: The evidence on cholera disease dynamics suggests that significant herd protection can result from a relatively small number of immunizations, particularly in endemic areas where there is some natural immunity among the population.

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Key Concept

Key Evidence: A multi-site study of cholera vaccination programs found that the vaccine was cost-effective in school- and community-based vaccination programs for children in India, Mozambique, and Indonesia.

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Key Evidence: Assuming 90% coverage, a 9-valent PCV (PCV9) program in The Gambia would prevent approximately 630 hospitalizations, 40 deaths, and 1000 DALYs, for the birth cohort over the first 5 years of life. The estimated cost would be $670 per DALY averted in The Gambia.

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Key Evidence: An analysis in Kenya found that, although the government will need to more than double its current vaccine budget to continue using PCV after GAVI support ends, continuing the vaccination will prevent more than 101,000 cases of invasive pneumoccocal disease and pneumonia, more than 14,000 deaths over an 11-year period, and would be cost-effective (cost per DALY of $153 by 2032), even at the full GAVI price of US$3.05 per dose.

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Key Concept

Key Evidence: A study looking at the impact of pneumococcal vaccine introduction and scaling up pneumonia treatment in Ethiopia found that 30-40% of all deaths averted by these interventions would be expected to occur in the poorest wealth quintile. The greatest resulting financial risk protection would also be concentrated among the bottom income quintile.

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Key Concept

Key Evidence: During a meningococcal meningitis epidemic in Burkina Faso, households spent, on average, US$90 for treatment and other direct costs for family members with the disease. These costs, the equivalent of one third of the country’s annual GDP per capita, were in addition to the loss of income and assets from family members caring for patients.

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Key Concept

Key Evidence: In rural Malawi, even though medical care for cholera is free-of-charge in the public sector, more than half of families had to borrow money or sell livestock or other assets to compensate for the lost wages of patients or caregivers and other costs (such as for food and transportation) incurred as a result of an episode of cholera.

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Key Evidence: Among families participating in a study in Western Cape, South Africa, 35% of mothers who were previously employed stopped working to care for children who had survived tuberculosis meningitis with permanent disabilities. 19% of families reported experiencing financial loss as a result of caring for these disabled children.

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Key Concept

Key Evidence: In rural Malawi, where medical care for cholera is free-of-charge, cholera still cost households, on average, US$66 in lost wages of the patient or caregiver and direct, non-medical costs, such as food and transportation. The direct cost to health facilities was $60 per case, twice as much as the 2016 per capita health budget for Malawi that year.

From the VoICE editors: Data on per capita health expenditures by country can be found in the WHO Health Expenditures database here: http://apps.who.int/nha/database/Select/Indicators/en

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Key Evidence: In a study in The Gambia – a setting where healthcare is free of charge to patients – pneumococcal disease nonetheless placed a heavy financial burden on families seeking treatment before arrival at the hospital, with families paying for transportation costs, drugs, diagnostic tests and even burial in the case of death. 50-80% of the cost of treating an episode of pneumococcal disease was born by the health system, which still left families to cover a cost up to 10 times their average daily household budget. In addition the estimated treatment cost for inpatient pneumonia of US$109 is nearly 4 times the annual per capita expenditure for health in The Gambia.

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Key Evidence: In Malawi, in 17% of cases where children were admitted to the hospital, and in 9% of cases where children were treated as outpatients for diarrhea, household costs associated with treating that episode, exceeded monthly income in a significant number of cases. The costs were significant enough to push families from each income level below the national poverty line for the month in which the illness occurred.

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Key Concept

Key Evidence: During the 2014-2016 Ebola epidemic in 3 West African countries, fear of the disease in neighboring Nigeria and misperceptions on how disease spreads negatively affected many sectors of the economy – retail, hospitality, airline industries, and certain agricultural sectors.

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Key Concept

Key Evidence: For every 6 children vaccinated against measles in a poor, largely rural community in South Africa, one additional grade of schooling was achieved.

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Key Concept

Key Evidence: Models based on demographic data from Ghana suggest that immunization would eliminate the childhood mortality risk associated with living in poverty and greatly diminish the increased risk of mortality borne by children whose parents have low levels of education.

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Key Concept

Key Evidence: Among families participating in a study in Western Cape, South Africa, 35% of mothers who were previously employed stopped working to care for children who had survived tuberculosis meningitis resulting in permanent disabilities. 19% of families reported experiencing financial loss as a result of caring for these disabled children.

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Key Concept

Key Evidence: In The Gambia, 58% of children who survived pneumococcal meningitis had long lasting negative health outcomes. Half had major disabilities such as mental retardation, hearing loss, motor abnormalities, and seizures.

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Key Evidence: In a systematic literature review of studies in Africa, it was found that 25% of children who survived pneumococcal or Hib meningitis had neuropsychological deficits.

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Key Concept

Key Evidence: Children in Western Cape, South Africa who were well enough to attend school after surviving tuberculosis meningitis, more than half had failed at least one school grade.

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Key Concept

Key Evidence: A 2019 analysis of survey data from school aged children in Ethiopia, India and Vietnam shows that children vaccinated against measles achieved 0.2 – 0.3 years of additional schooling compared to children who did not receive the measles vaccine.

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Key Evidence: For every 6 children vaccinated against measles in a poor, largely rural community in South Africa, one additional grade of schooling was achieved.

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Key Concept

Key Evidence: Wealth and mother’s education are significant predictors of vaccination rates in both urban and rural settings. However, low paternal education, lack of antenatal care, and home births were significantly associated with low vaccination rates only in rural settings. This suggests the need for tailored vaccine programs.

From the VoICE Editors: This study compared the significance of risk factors for low vaccination rates in rural versus urban settings in Tanzania.

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Key Evidence: Nigerian Demographic Health Survey data suggests that community literacy influences immunization status. Children in communities with low levels of illiteracy were 82% less likely to be fully immunized than children in communities with medium levels of illiteracy.

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Key Evidence: Children of mothers with secondary education or higher were significantly more likely to be fully immunized than children of mothers with lower levels of educational attainment.

From the VoICE editors: Data was collected in the Democratic Republic of Congo from a cross-sectional survey (the Demographic and Health Survey) and analyzed in the aggregate. However, the authors note high variation in coverage across localities. 

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Key Evidence: A study conducted in Eastern Uganda found that Ugandan children whose mothers had some secondary schooling were 50% more likely to have received scheduled vaccinations by 6 months of age than children whose mothers had attended school only through primary level. This effect became more pronounced with delivery of the later doses of each vaccine (OPV2, 3 & DPT-HB-Hib 2,3).

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Key Evidence: Children born to mothers in Southwest Nigeria who had no formal education were four times more likely to be unvaccinated or partially vaccinated than those born to mothers who completed primary school and were six times more likely to be partially vaccinated or unvaccinated than children whose mothers completed a post-secondary education.

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Key Concept

Key Evidence: Maternal education benefits immunization rates of all community members, not only mothers’ own children. In Nigeria, children’s odds of being fully immunized improved by 1.06 times for every additional year of education the mothers received. Children’s odds of being fully immunized increased by 1.2 times for each additional year of maternal education in the community.

From the VoICE Editors: The authors controlled for factors including maternal employment, average household wealth, whether the child was born in a hospital, urban status of communities, and geographic location of communities.

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Key Evidence: Data from the Kenya Demographic and Health Survey show that women with a primary school education were 2 to 5 times more likely to have their infants vaccinated (depending on the vaccine) and women with a secondary school education were 2.5 to 9 times more likely to have their infants vaccinated than mothers with less than a primary education or no education [after adjusting for wealth, age, religion and other variables]. Targeted communications activities to sensitize less educated women on the value of vaccination could be a short-term measure to close this gap.

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Key Concept

Key Evidence: In a systematic review of qualitative research from low- and middle-income countries, women’s low social status was shown to be a barrier to their children accessing vaccinations. Specific barriers included access to education, income, resource allocation, and autonomous decision-making related to time. The authors suggest that expanding the responsibility for children’s health to both parents (mothers and fathers) may be one important element in removing persistent barriers to immunization often faced by mothers.

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Key Evidence: A study looking at the relationship between gender roles and full immunization coverage of children in Nigeria found that children of mothers who did not have decision-making autonomy were half as likely to be fully immunized than mothers with autonomy. To further assess the roles of gender and relationship power, children were nearly twice as likely to be fully vaccinated in households where only the mother contributed to household earnings compared to children whose parents contributed equally.

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Key Evidence: The level of women’s community-level autonomy is associated with an increased number of children immunized above and beyond that which is seen with individual-level women’s autonomy. These results indicate that empowering women within households not only improves the individual mother’s children’s health, but also serves to improve the lives of other children within the community.

From the VoICE editors: This analysis is from the 2011 Ethiopian Demographic and Health Survey that investigated the relationship between individual- and community-levels of women’s autonomy and children’s immunization status.

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Key Evidence: A systematic review of studies from countries in Africa and Southeast Asia investigated the relationship between a woman’s “agency” (defined as the woman’s ability to state her goals and to act upon them with motivation and purpose) and childhood immunizations in lower-income settings. The review found a general pattern among studies in which higher agency among mothers was associated with higher odds of childhood immunizations. Empowering women in these settings shows promise as a means to improve child health.

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Key Concept

Key Evidence: An ecological study designed to investigate the association between child mortality rates and gender inequality using the United Nations Development Programme’s Gender Inequality Index (GII), showed that low- and middle-income countries have significantly higher gender inequality and under-5 mortality rates than high-income countries. Greater gender inequality was significantly correlated with lower immunization coverage and higher neonatal, infant, and under-5 mortality.

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Key Concept

Key Evidence: Among both HIV positive and HIV negative parents in a study in Kenya, 99% of pneumococcal strains found and tested were resistant to one or more antibiotics. HIV positive parents carried 16% more strains that were resistant to penicillin than those carried by HIV negative parents.

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Key Evidence: In a study of national surveillance records in South Africa, HIV positive people over 5 years of age were found to have a 43-fold risk of invasive pneumococcal disease compared to HIV negative person. This risk was highest among children age 5-19 who were found have a more than 120-fold risk of invasive pneumococcal disease compared to HIV negative uninfected children of the same age. 90% of South Africa’s invasive pneumococcal disease cases during the 5 year period occurred in the 18% of the population who are HIV positive.

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Key Evidence: Prior to the introduction of PCV, adults with HIV in a rural area of Kenya were nearly five times more likely to have pneumococcal pneumonia than non-infected adults, and the majority of cases with bacteremia (blood infection) occurred in HIV positive individuals.

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Key Concept

Key Evidence: Two years after the introduction of 10-strain pneumococcal conjugate vaccine (PCV-10) in Kenya, the percent of HIV-positive adults who carried pneumococcal bacteria declined significantly (from 43% to 28%), but did not decline in HIV-negative adults. However, the reduction in carriage of pneumococcal strains that are in PCV10 declined significantly in both HIV-positive and HIV-negative adults. This reduction was still four times higher in HI- positive vs. HIV-negative adults (2.8% vs. 0.7%), indicating that HIV positive adults continue to be at considerably higher risk of invasive pneumococcal disease than HIV-uninfected adults.

From the VoICE Editors: Nasopharyngeal carriage is an indicator of the risk for invasive pneumococcal disease and pneumonia. 

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Key Evidence: Models based on demographic data from Ghana suggest that immunization would eliminate the childhood mortality risk associated with living in poverty and greatly diminish the increased risk of mortality borne by children whose parents have low levels of education.

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Key Concept

Key Evidence: Over a five-year period following the introduction of PCV for infants in Kenya, the incidence of pneumococcal pneumonia in adults with HIV in a rural area fell sharply — narrowing the gap in incidence rates between HIV-infected and non-infected adults — as a result of both the herd effects of the vaccine and improved access to HIV care during this period.

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Key Evidence: A review of evidence for the use of pneumococcal conjugate vaccine in South Africa showed that children who are HIV positive are at significantly increased risk of pneumococcal disease, and so will benefit the most from vaccination, despite decreased vaccine efficacy in this group compared to healthy children.

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Key Evidence: A large randomized controlled trial of a pneumococcal conjugate vaccine in South Africa found that use of the vaccine prevented 10 times as many cases of pneumococcal pneumonia in HIV positive children than in HIV negative children.

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Key Concept

Key Evidence: A study of Kenyan children under 5 years of age found that immunization with polio, BCG, DPT, and measles to be protective against stunting in young children (27% less likely to be stunted than unimmunized children under age 2 years). In addition, children with diarrhea and cough in the 2 weeks prior to the survey were 80-90% more likely to be underweight or to suffer from wasting.

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Key Evidence: An analysis of the association between undernutrition and mortality in young children revealed that in 60% of deaths due to diarrhea, 52% of deaths due to pneumonia, 45% of deaths due to measles and 57% of deaths attributable to malaria, undernutrition was a contributing factor.

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Key Concept

Key Evidence: An analysis of the association between undernutrition and mortality in young children revealed that in 60% of deaths due to diarrhea, 52% of deaths due to pneumonia, 45% of deaths due to measles and 57% of deaths attributable to malaria, undernutrition was a contributing factor.

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Key Concept

Key Evidence: A study looking at the impact of pneumococcal vaccine introduction and scaling up pneumonia treatment in Ethiopia found that 30-40% of all deaths averted by these interventions would be expected to occur in the poorest wealth quintile. Scaling up PCV13 to levels achieved with DTP3 in Ethiopia would be expected to avert nearly 3000 child deaths and 60,000 episodes of pneumococcal pneumonia annually, not including any potential herd benefit. A publicly financed program to scale up pneumococcal vaccines would cost about US$40 per year of healthy life gained.

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Key Concept

Key Evidence: Rates of vaccination in all studied countries were highest and risk mortality lowest in the top two wealth quintile’s coverage. Countries differed in the relative inequities in these two underlying variables. Cost per DALYs averted is substantially greater in the higher quintiles. In all countries, the greatest potential vaccine benefit was in the poorest quintiles; however, reduced vaccination coverage lowered the projected vaccine benefit.

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Key Evidence: A package of 5 vaccines was delivered, and it was found that children from poorer households benefited more in terms of health outcomes from immunization than did those from relatively wealthier households. Results suggest that most of the risk of dying before age five can be eliminated with full immunization in the severely health-deprived setting.

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Key Concept

Key Evidence: Non-Somali children in Kenya in the poorest households were nearly three times as likely to be unvaccinated than children from middle-income households, while wealthier children were significantly less likely to be unvaccinated.

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Key Evidence: In a systematic review of qualitative research from low- and middle-income countries, women’s low social status was shown to be a barrier to their children accessing vaccinations. Specific barriers included access to education, income, resource allocation, and autonomous decision-making related to time. The authors suggest that expanding the responsibility for children’s health to both parents (mothers and fathers) may be one important element in removing persistent barriers to immunization often faced by mothers.

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Key Evidence: In Tanzania, poverty was found to have a negative effect on receiving vaccines on time (at the recommended age). Children in the wealthiest quintile experienced 19% fewer delays for BCG vaccination, 23% fewer delays for the third dose of DTP vaccination, and 31% fewer delays for the first dose of measles-containing vaccine compared to children of the poorest quintile.

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Key Concept

Key Evidence: A package of 5 vaccines was delivered, and it was found that children from poorer households benefited more in terms of health outcomes from immunization than did those from relatively wealthier households. Results suggest that most of the risk of dying before age five can be eliminated with full immunization in the severely health-deprived setting.

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Key Concept

Key Evidence: This study from South Africa demonstrates significant declines in invasive pneumococcal disease cases caused by bacteria that are resistant to one or more antibiotics. In fact, the rate of infections resistant to two different antibiotics declined nearly twice as much as infections that could be treated with antibiotics.

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Key Concept

Key Evidence: A study of sickle cell disease patients in Ghana found that pneumoccocus bacteria found in their noses and throats had high rates of drug resistance with 37% of positive samples resistant to penicillin and 34% resistant to multiple drugs (typically penicillin + tetracycline + cotrimoxazole).

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Key Concept

Key Evidence: Among both HIV positive and HIV negative parents in a study in Kenya, 99% of pneumococcal strains found and tested were resistant to one or more antibiotics. HIV positive parents carried 16% more strains that were resistant to penicillin than those carried by HIV negative parents.

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Key Evidence: Two years after the introduction of 10-strain pneumococcal conjugate vaccine (PCV-10) in Kenya, the percent of HIV-positive adults who carried pneumococcal bacteria declined significantly (from 43% to 28%), but did not decline in HIV-negative adults. However, the reduction in carriage of pneumococcal strains that are in PCV10 declined significantly in both HIV-positive and HIV-negative adults. This reduction was still four times higher in HI- positive vs. HIV-negative adults (2.8% vs. 0.7%), indicating that HIV positive adults continue to be at considerably higher risk of invasive pneumococcal disease than HIV-uninfected adults.

From the VoICE Editors: Nasopharyngeal carriage is an indicator of the risk for invasive pneumococcal disease and pneumonia. 

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Key Concept

Key Evidence: According to a study in a hypothetical endemic population, vaccination using typhoid conjugate vaccine will reverse the current increase in the percent of chronic carriers of the disease who are antibiotic resistant, if at least 50% of the target population is vaccinated. This would deplete an important “reservoir” of antibiotic resistant typhoid.

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Key Concept

Key Evidence: Children living in the Yida refugee camp in South Sudan in 2013 were found to have an elevated rate of pneumonia infections likely due to malnutrition, overcrowding, and inadequate shelter. Using these data, the CDC estimated that the use of Hib and pneumococcal vaccines in children under 2 years of age in the camp would be cost-effective under all dosing scenarios evaluated. Medecines Sans Frontiers (MSF) provided medical services to this refugee camp and found delivery of these vaccines to be feasible and effective in this setting.

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Key Concept

Key Evidence: Researchers investigating the causes of a measles outbreak in Burkina Faso that occurred despite a recent mass vaccination campaign found that migration to and from Cote d’Ivoire was a major risk factor for children. Unvaccinated children who developed measles were 8.5x more likely to have recently traveled to Cote d’Ivoire than unvaccinated children who had not traveled across the border. Children returning to Burkina Faso after a period of time in Cote d’Ivoire were less likely to have been vaccinated due to low routine coverage of measles vaccines in Cote d’Ivoire. Conversely, unvaccinated children from Burkina Faso who traveled to Cote d’Ivoire and returned were more likely to be exposed to measles and thus had a higher rate of disease than children who never visited Cote d’Ivoire.

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Key Concept

Key Evidence:A study from South Africa shows that reduction in birth rate (fertility) can yield certain socioeconomic benefits. These include 1) a decrease in ratio of economically dependent people 2) increased per capita labor force and 3) increased savings. These savings can be invested in physical human capital which aids in economic growth. As average family sizes decrease, parents are likely to invest more on their child’s health and education. This in turn offers potential benefits to long term productivity in adulthood.

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Key Concept

Key Evidence: A study in Kenya revealed that immunization with polio, BCG, DPT and measles had protective effects with respect to stunting in children under 5 years of age. In children under the age of 2 years, immunized children were 27% less likely to experience stunting when compared to unimmunized children. Additionally, children who suffered from cough or diarrhea in the 2 weeks prior to the study showed an 80-90% higher probability of being underweight or experiencing wasting.

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Key Concept

Key Evidence: A study in rural Kenya, over a 4-year period following the introduction of the 10-strain pneumococcal conjugate vaccine for infants, that included a catch-up vaccination campaign for children 12-59 months of age, suggests that the catch-up vaccination for older birth cohorts may have been a key factor in protecting unvaccinated individuals and speeding up the reduction of the disease in the community. In contrast, a study in The Gambia, where no catch-up campaign took place, found no herd effects during the first three years following the introduction of PCV-13 for infants.

From the VoICE Editors: The Gambia study publication referenced can be found at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4909992/ 

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Key Concept

Key Evidence: Multiple studies show that

  1. Diarrhea and pneumonia impair children’s growth and that underlying malnutrition is a major risk factor for these conditions.
  2. “Episodes of diarrhea may predispose to pneumonia in undernourished children” and
  3. Immunization against influenza (in mothers) and Streptococcus pneumoniae may improve infant growth. In addition, new studies from Bangladesh, Colombia, Ghana, and Israel further support the paradigm that malnutrition is a key risk factor for diarrhea and pneumonia.

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Key Concept

Key Evidence: A prospective case-control study conducted in several developing countries found that children with moderate-to-severe diarrhea grew significantly less in length in the two months following their episode compared to age- and gender-matched controls.

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Key Evidence: A study of Kenyan children under 5 years of age found that children with diarrhea and cough in the 2 weeks prior to the survey were 80-90% more likely to be underweight or to suffer from wasting.

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Key Concept

Key Evidence: In a recent review of data from developing countries, researchers found that episodes of diarrhea may predispose undernourished children to pneumonia.

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Key Concept

Key Evidence: Assuming 90% coverage, a program in The Gambia using a 9-valent PCV (PCV9) would prevent approximately 630 hospitalizations, 40 deaths, and 1000 DALYs over the first 5 years of life of a birth cohort. The estimated cost would be $670 per DALY averted in The Gambia.

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Key Evidence: In one of the first studies of real-world use of pneumococcal conjugate vaccine (PCV) in Africa, the 10-strain vaccine introduced in Kenya for infants and provided to all children under five in “catch-up” campaigns reduced the incidence of any cause of pneumonia confirmed by a chest X-ray by nearly half (48%) in children 2-59 months of age over a five-year period. This sharp reduction in radiological-confirmed pneumonia is more than twice the reduction seen in several clinical trials of PCV in Africa and Latin America which was around 20-23%.

From the VoICE Editors: The sharp reduction in radiological-confirmed pneumonia as a result of immunization in this study is likely because – unlike in some clinical trials – the herd effects of the vaccine on unvaccinated children were prospectively captured in the study.

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Key Evidence: In Rwanda, the number of hospital admissions for diarrhea and rotavirus fell substantially after rotavirus vaccine (RVV) introduction, including among older children age-ineligible for vaccination. This suggests indirect protection through reduced transmission of rotavirus. Two years after RVV introduction, the country had nearly 400 fewer hospital admissions for diarrhea among young children.

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Key Concept

Key Evidence: In Gambia, 58% of children who survived a bout of pneumococcal meningitis “had clinical sequelae; half of them had major disability preventing normal adaptation to social life” (mental retardation, hearing loss, motor abnormalities, seizures).

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Key Evidence: A systematic literature review analyzing data from 21 African countries revealed that bacterial meningitis is associated with high case fatality and frequent neurophysiological sequelae. Pneumococcal and Hib meningitis contribute to one third of disease related mortality. They also cause clinically evident sequalae in 25% of survivors prior to hospital discharge. The three main causes of bacterial meningitis- Haemophilus influenzae type B; Streptococcus pneumoniae (pneumococcus) and Neisseria meningitidis (meningococcus) are vaccine preventable, routine use of conjugate vaccines have potential for significant health and economic benefits.

From the VoICE Editors: Neuropsychological sequelae includes hearing loss, vision loss, cognitive delay, speech/language disorder, behavioural problems, motor delays/impairment, and seizures. 

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Key Concept

Key Evidence: An analysis of data from three studies showed that the rates of severe pneumonia in infants in their first six months of life was 20% lower overall in infants whose mothers received the influenza vaccination during pregnancy than in infants whose mothers had not, and the rates of severe pneumonia was 56% lower during periods when influenza circulation was highest. These findings correspond with evidence that influenza infection predisposes individuals to pneumococcal infection.

From the VoICE Editors: The incidence rate of severe pneumonia in the vaccine group compared to the control group was 43% lower in South Africa, 31% lower in Nepal, but not significantly different in Mali.

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Key Concept

Key Evidence: The expertise and assets gained through efforts to eradicate polio at least partially explain the improvement between 2013 and 2015 in vaccination coverage of DPT3 in six out of ten “focus” countries of the Polio Eradication Endgame strategic plan. This includes substantial increases in vaccination rates in India, Nigeria, and Ethiopia, which, combined, reduced the number of children not fully vaccinated with DPT by 2 million in 2 years.

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Key Concept

Key Evidence: The Government of Nigeria used the Incident Management System (IMS) to establish a national Emergency Operations Center (EOC) as part of a new national emergency plan for the global polio eradication initiative. The use of IMS through the EOC changed the operational tempo, accountability measures, and programmatic success of the polio program. This existing infrastructure was in place and leveraged to contain the outbreak of Ebola.

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Key Concept

Key Evidence: In Rwanda, HPV vaccine introduction through a new school-based delivery program provided the opportunity to offer additional health services to all school-children (girls and boys), including health promotion sessions, de-worming and opportunities for voluntary, free circumcision.

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Key Concept

Key Evidence: The Government of Nigeria used the Incident Management System (IMS) to establish a national Emergency Operations Center (EOC) as part of a new national emergency plan for the global polio eradication initiative. The use of IMS through the EOC changed the operational tempo, accountability measures, and programmatic success of the polio program. This existing infrastructure was in place and leveraged to contain the outbreak of Ebola.

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Key Concept

Key Evidence: In Rwanda, HPV vaccine introduction through a new school-based delivery program provided the opportunity to offer additional health services to all school-children (girls and boys), including health promotion sessions, de-worming and opportunities for voluntary, free circumcision.

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Key Concept

Key Evidence: Two years after rotavirus vaccine introduction in Rwanda, the country saw nearly 400 fewer hospital admissions for diarrhea among young children at 24 district hospitals.

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Key Evidence: A study in four hospitals in Botswana found that over a two-year period following the introduction of rotavirus vaccine, hospitalizations from all causes of diarrhea fell by one-third in infants (0-11 months old), and by nearly one-quarter in all children under five years of age. Ninety percent of infants 4-11 months old in the study population received at least one dose of the vaccine, and 75% received both doses during this period. The vaccine’s impact was most apparent during the rotavirus season when the average number of hospitalizations from diarrhea fell 43% among infants and by one-third among all children under five.

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Key Concept

Key Evidence: Wealth and mother’s education are significant predictors of vaccination rates in both urban and rural settings.  However, low paternal education, lack of antenatal care, and home births were significantly associated with low vaccination rates only in rural settings. This suggests the need for tailored vaccine programs.

From the VoICE editors: This study compared the significance of risk factors for low vaccination rates in rural versus urban settings in Tanzania. 

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