In this paper we examine several definitions of vaccine efficacy (VE) that we found in the literature, for diseases that express themselves in outbreaks, that is, when the force of infection grows in time, reaches a maximum and then vanishes. The fact that the disease occurs in outbreaks results in several problems that we analyse. We propose a mathematical model that allows the calculation of VE for several scenarios.
View Article and Find Full Text PDFObjectives: To estimate the incidence of dengue infection across geographically distinct areas of Brazil.
Methods: This prospective, household-based, cohort study enrolled participants in five areas and followed them up for up to 4 years (2014-2018). Dengue seroprevalence was assessed at each scheduled visit.
We described pertussis epidemiological trends in Brazil between 2010 and 2015. We also assessed tetanus, diphtheria and acellular pertussis (Tdap) vaccine coverage among pregnant women from 2014, the year of the introduction of Tdap maternal immunization recommendation in Brazil, to 2016. Epidemiological data for incidence, prevalence, hospitalization, mortality, and maternal vaccination coverage were calculated based on the Brazilian public surveillance databases.
View Article and Find Full Text PDFBackground: Few population-based studies of infectious etiologies of fever-rash illnesses have been conducted. This study reports on enhanced febrile-rash illness surveillance in Campinas, Brazil, a setting of low measles and rubella virus transmission.
Methods: Cases of febrile-rash illnesses in individuals aged <40 years that occurred during the period 1 May 2003-30 May 2004 were reported.
Objective: To evaluate and validate the information concerning measles and rubella from the Brazilian National Disease Notification System (BNDNS) (Sistema Nacional de Informação de Agravos de Notificação, or SINAN) for Campinas, a large city in the state of São Paulo, Brazil, using as a reference the data from a control system, the Syndromic Surveillance System for Fever and Exanthem (SSSFE) (Sistema de Vigilância Sindrômica de Febre e Exantema, or VigiFEx), which operated from May 2003 through June 2004.
Method: In our study we compared: (1) annual data from BNDNS for the years 1999 through 2003 and (2) data from BNDNS and data from SSSFE for the period of June 2003 through May 2004. We analyzed the rate of completion for key fields (record number, date of notification, and city of notification) as well as for name of disease, date of first symptoms, name of patient, birth date and age, sex, city of residence, date of investigation, immunization history, presence of exanthem, date at start of exanthem, presence of fever, suspected cases among pregnant women, signs and symptoms, date of collection of first sample, results with the sample, virus isolation, final classification, criteria for confirmation/exclusion of cases, diagnosis of excluded patients, development of the case, and date of closure.