ETD

Archivio digitale delle tesi discusse presso l'Università di Pisa

Tesi etd-03222007-164121


Tipo di tesi
Tesi di laurea specialistica
Autore
Del Fava, Emanuele
Indirizzo email
e.delfava@gmail.com
URN
etd-03222007-164121
Titolo
Modelling forces of infection for mumps, rubella and parvovirus: a statistical perspective
Dipartimento
ECONOMIA
Corso di studi
STATISTICA PER L'ECONOMIA E PER L'AZIENDA
Relatori
Relatore Prof. Manfredi, Pietro
Parole chiave
  • fractional polynomials
  • generalized linear models
  • nonlinear least squares models
  • confidence intervals for a binomial proportion
  • force of infection
  • seroprevalence
  • serological survey
Data inizio appello
26/04/2007
Consultabilità
Completa
Riassunto
The force of infection is a fundamental epidemiological parameter of infectious diseases. For many infectious diseases it is assumed that the force of infection is age-dependant. Although the force of infection can be estimated directly from a follow up study, it is much more common to have cross-sectional seroprevalence data from which the seroprevalence and the force of infection can be estimated. Here we propose to model the seroprevalence with three different parametric models: a nonlinear least squares model proposed by Farrington (1990); a logistic model, estimated using the generalized linear models; two fractional polynomial models of different order. We illustrate the methods on three seroprevalence samples, taken by the literature, regarding the following infectious diseases: mumps, rubella and parvovirus. Besides, in order to determine the optimal sample size for a serological survey, we show the serious problems of the standard confidence interval for a binomial proportion and we introduce some alternative confidence intervals proposed by the literature.
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