VoICE : Search Immunization Evidence
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.
Malnourished children are at greater risk of death from potentially vaccine-preventable diseases than children with no significant signs of malnourishment.
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.
A study of children under 5 years of age in Dhaka Bangladesh found that severely malnourished children were at a significantly increased risk (nearly 8x) of death from diarrhea than those who were not severely malnourished.
Sustaining immunization activities and preventing VPD (vaccine preventable disease) outbreaks during conflict can be achieved through preemptive preparedness measures and concerted programmatic and financial support from governments and partners.
During the conflict in Yemen, efforts spearheaded by WHO, with coordination among partners and effective use of resources, especially GAVI, resulted in continued high pentavalent vaccine coverage decreasing only 3% from 2010 to 2015. Yemen also remained polio-free through 2015 and smoothly introduced two new vaccines (MR and IPV).
During the humanitarian crisis in the Syrian Arab Republic, the constant support from WHO, UNICEF and local NGOs resulted in immunizations against VPDs reaching over 90% of children.
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).
In a study modeling the economic impact of immunization in 41 low- and middle-income countries, the authors estimate that 24 million cases of medical impoverishment would be averted through the use of vaccines administered from 2016-2030. The largest proportion of poverty cases averted would occur in the poorest 40% of these populations, demonstrating showing that vaccination can provide financial risk protection to the most economically vulnerable.
The interruption of disease outbreaks through vaccination can yield a significant return on investment.
Considering both the direct and indirect costs, researchers in the Netherlands estimated that the preventative immunization of Dutch healthcare workers (HCW) against pertussis (to reduce exposure and transmission contributing to outbreaks) results in a return on investment of 4 Euros to every 1 euro invested. This projection assumes an outbreak of pertussis once every 10 years.
The greatest cost savings to be had by introducing new vaccines and increasing immunization coverage would occur in countries and regions with high disease burden and/or large populations
In a modeled analysis of the economic impact of vaccine use in the world’s 72 poorest countries, for countries included in the analyses from the African region, scaling up coverage of the Rotavirus (RVV) vaccine to 90% was projected to result in more than $900 million in treatment costs averted.
Immunizing populations during complex humanitarian emergencies can help protect populations who are especially vulnerable to malnutrition and its effects.
Malnutrition is a leading contributor to morbidity and mortality during humanitarian emergencies and a cyclical relationship exists between malnutrition and infectious diseases. Universal immunization programs have been shown to improve the height and weight measurement markers associated with malnutrition.
An analysis of the impact of rotavirus vaccine in 25 gavi 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 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.
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.
A study of measles vaccine in Bangladesh found that children from the poorest quintile were more than twice as likely to die as those from the least quintile in the absence of measles vaccination. The difference in mortality between unvaccinated and vaccinated was statistically significant (p<0.10) and robust across alternative measures of socioeconomic status.
Undernutrition is a significant risk factor for disease and death in young children, making vaccines especially critical for malnourished children
An analysis of undernutrition and mortality in young children found that among the principal causes of death, 60.7% of deaths as a result of diarrhea, 52.3% of deaths as a result of pneumonia, 44.8% of deaths as a result of measles, and 57.3% of deaths as a result of malaria are attributable to undernutrition.
Vaccination programs such as those for Rotavirus have shown a significant short-term return on investment.
In a UK cost-effectiveness analysis, which takes into account herd effect, the budget impact analysis demonstrated that the introduction of a rotavirus vaccine (RVV) program could pay back between 58-96% of the cost outlay for the program within the first 4 years.
In an economic evaluation of vaccination against rotavirus conducted in Italy, it was shown that as early as the second year after rotavirus vaccine introduction, the vaccine cost would be more than offset by savings from prevention of disease cases and hospitalizations.
The indirect benefit of immunization to unvaccinated individuals (herd immunity) increases the cost-effectiveness of vaccines.
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.
This study based on active surveillance in the US before and after introduction of PCV estimated 38,000 cases of invasive pneumococcal disease were averted in the first 5 years of vaccine use, at an estimated cost of US$112,000 per life year saved. However, after inclusion of 71,000 cases of disease that were prevented through herd effects, researchers estimate a cost of US$7,500 per life year saved.