Yellow Fever Vaccine Seroconversion in Travelers

Kay, Allison; Chen, Lin H.; Sisti, Maggie; Monath, Thomas P.

doi:10.4269/ajtmh.2011.11-0363

Cited by 10 publications

(11 citation statements)

References 12 publications

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“…As can be seen, the difference of values in Figures 1 and 2 occurs not only between simulated and experimental data, but also in the results of distinct studies, see, [41][42] and among individuals in the same study. This is an implicit characteristic of biological experiments.…”

Section: Computational Resultsmentioning

confidence: 78%

Mathematical modeling based on ordinary differential equations: A promising approach to vaccinology

Bonin

Fernandes

Santos

et al. 2016

Human Vaccines & Immunotherapeutics

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New contributions that aim to accelerate the development or to improve the efficacy and safety of vaccines arise from many different areas of research and technology. One of these areas is computational science, which traditionally participates in the initial steps, such as the pre-screening of active substances that have the potential to become a vaccine antigen. In this work, we present another promising way to use computational science in vaccinology: mathematical and computational models of important cell and protein dynamics of the immune system. A system of Ordinary Differential Equations represents different immune system populations, such as B cells and T cells, antigen presenting cells and antibodies. In this way, it is possible to simulate, in silico, the immune response to vaccines under development or under study. Distinct scenarios can be simulated by varying parameters of the mathematical model.As a proof of concept, we developed a model of the immune response to vaccination against the yellow fever. Our simulations have shown consistent results when compared with experimental data available in the literature. The model is generic enough to represent the action of other diseases or vaccines in the human immune system, such as dengue and Zika virus. KEYWORDS computational science; computational modeling; computational immunology; computational vaccinology; immune system; ordinary differential equations; yellow fever

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Section: Computational Resultsmentioning

confidence: 78%

Mathematical modeling based on ordinary differential equations: A promising approach to vaccinology

Bonin

Fernandes

Santos

et al. 2016

Human Vaccines & Immunotherapeutics

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“…Probably, this was due to multiple exposures and/or vaccinations. No indicative data were confirmed, because no consensus was found in the literature regarding the higher titers shown by Caucasians than by Blacks and Hispanics, as well as by men than by women 20,[22][23][24] . In a Brazilian study, a lower seroconversion rate was observed on antibody levels after vaccination against yellow fever in 12-month-old children who simultaneously received the triple viral vaccine than in those who received the 30-day interval vaccination.…”

Section: Discussionmentioning

confidence: 79%

“…There is no consensus on the titration conferring immunity. However, the values used as positive, i.e., values more than 10 are well accepted in the literature 10,11,19,21,22 .…”

Section: Discussionmentioning

confidence: 99%

Serologic assessment of yellow fever immunity in the rural population of a yellow fever-endemic area in Central Brazil

Machado

Vasconcelos

Silva

et al. 2013

Rev. Soc. Bras. Med. Trop.

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Introduction:The yellow fever epidemic that occurred in 1972/73 in Central Brazil surprised the majority of the population unprotected. A clinical-epidemiological survey conducted at that time in the rural area of 19 municipalities found that the highest (13.8%) number of disease cases were present in the municipality of Luziânia, State of Goiás. Methods: Thirty-eight years later, a new seroepidemiological survey was conducted with the aim of assessing the degree of immune protection of the rural population of Luziânia, following the continuous attempts of public health services to obtain vaccination coverage in the region. A total of 383 volunteers, aged between 5 and 89 years and with predominant rural labor activities (75.5%), were interviewed. The presence of antibodies against the yellow fever was also investigated in these individuals, by using plaque reduction neutralization test, and correlated to information regarding residency, occupation, epidemiological data and immunity against the yellow fever virus. Results: We found a high (97.6%) frequency of protective titers (>1:10) of neutralizing antibodies against the yellow fever virus; the frequency of titers of 1:640 or higher was 23.2%, indicating wide immune protection against the disease in the study population. The presence of protective immunity was correlated to increasing age. Conclusions: This study reinforces the importance of surveys to address the immune state of a population at risk for yellow fever infection and to the surveillance of actions to control the disease in endemic areas.

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“…Schwartz et al, identified high rates of cross-reactivity in the anti-DENV Panbio IgG ELISA when the patients were previously vaccinated against YF and JE, overestimating past DENV exposure when using this assay (16). Antibody cross-reactivity may depend on the time frame of vaccination in the context of testing for anti-DENV IgG (17).…”

Section: Discussionmentioning

confidence: 99%

Optimization of the Cutoff Value for a Commercial Anti-Dengue Virus IgG Immunoassay

Marrero-Santos¹,

Beltrán²,

Carrión-Lebrón³

et al. 2013

Clin. Vaccine Immunol.

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A commercial anti-dengue virus (anti-DENV) indirect IgG enzyme-linked immunosorbent assay (ELISA) for serological diagnosis was evaluated for its utility in determining previous DENV exposure in U.S. travelers. The Boston Area Travel Medicine Network clinics used Focus Diagnostics anti-DENV IgG ELISA to measure anti-DENV IgG antibodies in 591 pretravel specimens from U.S. residents who had traveled to countries where dengue is endemic. When using the manufacturer's index cutoff value for this ELISA, false-positive results were observed that overestimated the perceived past DENV exposure in U.S. travelers. Validation of 121 of these anti-DENV IgG results by plaque reduction neutralization test (PRNT) was used for receiver operating characteristic (ROC) curve optimization of the index cutoff value from 1 to 3.0, improving the specificity of the anti-DENV IgG ELISA from 24% to 95.7%. Additionally, previous vaccination with yellow fever virus contributed to 52.8% of the false-positive rate in the anti-DENV IgG ELISA results. Optimization of the cutoff value of the anti-DENV IgG ELISA provided better interpretation and confidence in the results and eliminated the need for confirmation by PRNT. The travel history of U.S. travelers was also useful for categorizing these travelers into groups for analysis of previous DENV exposure. Dengue is a major, global health problem, with an estimated 2.5 billion people at risk of contracting the disease and over 50 million infections annually (1). Dengue virus (family Flaviviridae, genus Flavivirus) is mosquito-borne with four antigenically distinct serotypes (DENV-1 to -4). There is sufficient antigenic homology among the four DENV serotypes and within the genus Flavivirus to create cross-reactivity in many immunoassays. This cross-reactivity is a diagnostic challenge when testing samples in regions where multiple DENV serotypes circulate and other flaviviruses cocirculate. Hence, immunoassays, such as the IgM enzyme-linked immunosorbent assay (ELISA) and the IgG ELISA, often require testing using a second method, such as a plaque reduction neutralization test (PRNT), to confirm the specificity of the antibody response (2).Anti-DENV IgG ELISAs are used to measure prevalence of previous infection by DENV and for conducting vaccine studies. The Boston Area Travel Medicine Network (BATMN) clinics used commercial anti-DENV IgG ELISAs to determine exposure to DENV in U.S. travelers; dengue is the leading cause of acute febrile illness in U.S. travelers returning from countries where DENV is endemic, as observed by GeoSentinal clinics (3). Among these patients, the Focus Diagnostics anti-DENV IgG ELISA had low specificity (24%) and high sensitivity (100%), as determined by the PRNT confirmatory test. Further evaluation of the cutoff value of the anti-DENV IgG ELISA was conducted in an attempt to increase the specificity of the test. MATERIALS AND METHODSStudy. Travelers were enrolled from five travel clinics from the BATMN group in Boston, MA, from August 2008 through June 2009. Appro...

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Yellow Fever Vaccine Seroconversion in Travelers

Cited by 10 publications

References 12 publications

Mathematical modeling based on ordinary differential equations: A promising approach to vaccinology

Mathematical modeling based on ordinary differential equations: A promising approach to vaccinology

Serologic assessment of yellow fever immunity in the rural population of a yellow fever-endemic area in Central Brazil

Optimization of the Cutoff Value for a Commercial Anti-Dengue Virus IgG Immunoassay

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