Doctoral Thesis
DOI
https://doi.org/10.11606/T.6.2020.tde-27032020-094749
Document
Author
Full name
Luiz Fernando Costa Nascimento
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2001
Supervisor
Committee
Almeida, Margarida Maria Mattos Brito de
Burattini, Marcelo Nascimento
Coutinho, Francisco Antonio Bezerra
Santos, Maria de Fátima de Castro Lacaz
Title in Portuguese
Estimativa do aparecimento de casos novos de tuberculose de acordo com a perda de eficácia da BCG ao longo do tempo: o papel da heterogeneidade e da revacinação
Keywords in Portuguese
BCG
Modelagem Matemática
Revacinação
Tuberculose
Abstract in Portuguese
Title in English
Estimation of new cases of tuberculosis in according with the loss of BCG eficacy along the time: the role of revaccination and heterogenety
Keywords in English
BCG
Mathematical Modelling
Revaccination
Tuberculosis
Abstract in English
Objective: To estimate the effects in incidence of the tuberculosis, in dynamical cohort followed for 30 years, we applied a mathematical model There were considered the possibilities of revaccination with BCG at 7 years or 12 years old and the efficay was assumed to be 15%, 50% or 80%. Methods: It was developed a mathematical model for computational simulation by the use of Fortran 90 language. It consisted of a dynamical cohort with 2000 newborns each year and the BCG vaccination occured at birth. The vaccinal efficacy was assumed to be 15%, 50% or 80%. The mathematical model had 6 compartiments and the transfer between they was modelled by a non linear, first order ordinary differential equations system. They did not consider the exogenous infection, endogenous rectivation nor AIDS interaction besides treatment, diagnosis and disregard. Nine file records were created by combination of the 3 vaccinal situations and the 3 efficacy possibilities. Results: With only one vaccination at birth, the computational simulations showed better results when the vaccinal efficacy was 80%; the annual incidence at the end of the cohort was between 125 cases/100000 persons and 173 cases/100000 persons; with a revaccination at 7 year old age the incidence changed between 66,2 cases/100000 persons and 99,7 cases/100000 persons. The better results were observed with a revaccination at 12 year old age when the incidence fell to 25 cases/100000 persons. The causes responsible for the fall were the enhanced immune activities of memory Th1 lymphocytes which are very important to kill the intracellular parasites. Conclusions: The mathematical modelling had demonstrated to be an important tool to estimate the effects of intervention measures in public health. So, when the parameter are changed better results can be obtained. The revaccination at 12 years old age has a better results and it has a minimal social operational and financial costs when compared with treatment of the diseased men and theirs communicants.