Browsing by Subject "Immunization"

Now showing 1 - 3 of 3
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    Cost-Effectiveness Analysis of Hepatitis A Vaccination in Contrasting Economic Environments
    (2018-12) Ghildayal, Nidhi
    Hepatitis A is one of the most common vaccine-preventable diseases. The virus is one of the greatest causes of foodborne infection, with epidemics often rapidly spreading through food and water sources. In its most severe cases, the disease can result in the need for a liver transplant or death. Complications can include recurring symptoms over several months. Most commonly, the disease causes a great amount of lost productivity and medical costs (WHO, 2010). In today’s rapidly changing world, many economies are developing quickly and countries are experiencing higher levels of sanitation, resulting in an epidemiological shift of the hepatitis A virus in many locations. The epidemiological shift occurs when children avoid being infected with the disease until a later age due to cleaner water sources, food, and hygiene practices in their environment; but if and when they are infected at this later age, the disease is much more severe and lost productivity costs are higher (Lopez et al, 2007). A hepatitis A vaccine exists, yet remains underutilized throughout much of the world (WHO, 2010). The vast number of hepatitis A cases, as well as the looming potential severity of an increasing average age of infection in many regions, creates a need for an evaluation of current hepatitis A vaccination strategies to ensure that those that are being implemented are most beneficial to society. Hepatitis A vaccination recommendations are often outdated or nonexistent. Several developed nations have vaccination strategies that target high-risk groups or children who live in areas with high incidence rates of the disease (Armstrong et al, 2007), but often fail to routinely reevaluate vaccination strategies once universal vaccination policies have been put in place (Plotkin et al, 2013). This is despite the cyclical nature of hepatitis A, which generally has a large increase in incidence every ten years, followed by a decrease to a rate lower than the previous baseline incidence (Fiore, 2004). With very few exceptions, developing countries generally have no recommendations and sparse resources dedicated to research on the disease (Quezada et al, 2008). In order to determine the strategies that will currently be most beneficial in terms of quality-adjusted life years (QALYs) and cost, I have created a model and conducted a cost-effectiveness analysis to investigate vaccination recommendation strategies in a More Economically Developed Country (MEDC), commonly known as a “developed” area, the United States, and a Less Economically Developed Country (LEDC), commonly known as a “developing” area, or in this case, the state of Rio de Janeiro, Brazil. In 2009, and currently, these two areas had different vaccination strategies for hepatitis A. The model ran two different scenarios – in the USA, I modeled the universal vaccination policy and what it would look like if it was taken away, and in Rio de Janeiro, I modeled no vaccination, as well as what it would look like if a universal vaccination policy was implemented. I have also conducted an analysis to show, if this epidemiological shift of the disease continues in these regions, what type of future burden hepatitis A may have in a hypothetical rapidly-developing country.
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    Enhancing the efficacy of a nicotine vaccine
    (2013-03) Cornish, Katherine E.
    Tobacco addiction is the leading cause of preventable death worldwide. Many people continue to smoke cigarettes despite clear detrimental health effects. Available smoking cessation therapies are only partially effective, making new treatment approaches necessary to increase smoking cessation rates. Immunization against nicotine features a different mechanism of action than currently available medications. As a pharmacokinetic antagonist, immunization against nicotine alters distribution, metabolism, and clearance of nicotine to attenuate nicotine-induced behavior in animal models. Nicotine vaccines in clinical trials show efficacy but are limited by the modest and highly variable nicotine-specific antibody (NicAb) concentrations produced. This thesis focuses on ways to improve efficacy of a nicotine vaccine by combining it with additional forms of immunotherapy. The first aim of this thesis examined the effects of supplementing vaccination against nicotine with individualized doses of Nic311, a nicotine-specific monoclonal antibody. Compared to either immunotherapy alone, combining active and passive immunization produced greater alterations in nicotine pharmacokinetics and nicotine-induced behavior using a locomotor activity model. Only small doses of Nic311 were necessary to supplement vaccine-generated NicAb concentrations to a previously effective threshold. This decreased cost and use of typically expensive monoclonal antibodies, potentially increasing viability of this approach in a clinical setting. The second aim of this thesis examined the effects of concurrent administration of two immunologically distinct nicotine immunogens in a bivalent vaccine over a range of vaccine formulations and immunization conditions. Immunogens were co-administered in a bivalent vaccine without compromising immunogenicity of either immunogen when delivered subcutaneously in alum, but not when delivered intraperitoneally in Freund's adjuvant. When combined in alum, immune responses elicited by the two immunogens were largely independent of one another. This suggests that subjects who responded poorly to one immunogen may have responded better to the second, immunologically distinct immunogen in the bivalent vaccine. These results indicate that the bivalent vaccine strategy is a feasible way to increase antibody concentrations above what can be achieved using one immunogen alone, but integrity of the response is highly dependent on vaccine formulation and administration conditions.
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    Examining the Variation in Child Vaccination Status by Maternal Vaccination and Birthing Place
    (2015-06) Fuchs, Erika
    Outbreaks of vaccine-preventable illnesses have occurred in recent years in pockets of children who are not up-to-date on their vaccinations, particularly among those whose parents have chosen to delay or refuse vaccinations for their children. It is essential to identify the at-risk children and the characteristics of parents who choose to delay or refuse vaccinations for their children. Numerous studies have focused on the beliefs and attitudes of parents regarding childhood vaccination, but few have focused on the association of other preventive health behaviors with childhood vaccination. Clustering of these behaviors is an important question in social epidemiology and could help in understanding underlying belief systems that influence health behaviors. Mothers who refuse influenza vaccinations during pregnancy report similar attitudes and beliefs to those who refuse vaccinations for their children, yet few studies have investigated relationships between child vaccination and other health behaviors. Additionally, mothers who choose to deliver their babies in out-of-hospital settings, a small, but growing, population in Minnesota, also report similar attitudes and beliefs, though this research is in its infancy. The objective of this study was to examine the variation in infant vaccination by maternal vaccination in pregnancy and maternal attitudes and beliefs using data from the Minnesota Pregnancy Risk Assessment Monitoring System and the Minnesota Immunization Information Connection. An exploratory study of the relationship between out-of-hospital birth and vaccination is also included. If relationships exist between these factors, there may be an opportunity for targeted vaccination interventions in subgroups of pregnant women or new mothers.