Marcos da Silva Freire

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Chimeric yellow fever (YF)-dengue type 2 (Den 2) viruses were constructed by replacing the premembrane (prM) and envelope (E) genes of YF 17D virus with those from Den 2 virus strains of south-east Asian genotype. Whereas viable chimeric viruses were successfully recovered when the YF 17D C gene and the Den 2 prM gene were fused at the signalase cleavage(More)
The yellow fever (YF) 17D virus is one of the most successful vaccines developed to data. Its use has been estimated to be over 400 million doses with an excellent record of safety. In the past 3 years, yellow fever vaccination was intensified in Brazil in response to higher risk of urban outbreaks of the disease. Two fatal adverse events temporally(More)
Dengue is one of the most important arboviral diseases in humans, and although efforts over the last decades have dealt with the development of a vaccine, this vaccine is not available yet. In order to evaluate the potential of a DNA vaccine based on the non-structural 1 (NS1) protein against dengue virus (DENV), we constructed the pcTPANS1 plasmid which(More)
Age-related seroprevalence studies that have been conducted in Brazil have indicated a transition from a high to a medium endemicity of hepatitis A virus (HAV) infection in the population. However, most of these studies have focused on urban populations that experience lower incidence rates of HAV infection. In the current study, the prevalence of anti-HAV(More)
Among the flaviviruses, dengue, with its four serotypes, has spread throughout the tropics. The most advanced vaccines developed so far include live attenuated viruses, which have been tested in humans but none has been licensed. Preclinical testing of dengue vaccine candidates is performed initially in mice and in nonhuman primates. In the latter the main(More)
To evaluate the genetic stability of the CAM-70 measles vaccine strain we have performed 10 serial passages of the seed lot virus FMS-7 in chicken embryo fibroblasts primary cultures (CEF) under production conditions. The nucleotide sequences of the seed lot virus, the virus from a vaccine vial (third passage) and from the 10th passage were determined and(More)
OBJECTIVE To compare the reactogenicity of three yellow fever (YF) vaccines from WHO-17D and Brazilian 17DD substrains (different seed-lots) and placebo. METHODS The study involved 1,087 adults eligible for YF vaccine in Rio de Janeiro, Brazil. Vaccines produced by Bio-Manguinhos, Fiocruz (Rio de Janeiro, Brazil) were administered ("day 0") following(More)
OBJECTIVE To compare the immunogenicity of three yellow fever vaccines from WHO-17D and Brazilian 17DD substrains (different seed-lots). METHODS An equivalence trial was carried out involving 1,087 adults in Rio de Janeiro. Vaccines produced by Bio-Manguinhos, Fiocruz (Rio de Janeiro, Brazil) were administered following standardized procedures adapted to(More)
In this work, the propagation of the 17DD yellow fever virus in Vero cells grown on Cytodex-1 microcarriers was evaluated. After verifying that upon infection the virus adsorption step could be performed under continuous agitation, experiments were carried out in spinners and sparged lab-scale stirred-tank bioreactor to evaluate the use of a commercial(More)
This work studied the replication sites of hepatitis A virus (HAV) in cynomolgus monkeys (Macaca fascicularis) after intravenous inoculation. The cynomolgus monkeys were inoculated with the Brazilian hepatitis A virus strain (HAF-203). Monkeys were euthanized on days 15, 30, 45 and 60 postinoculation (pi). Liver samples, submandibular salivary gland,(More)