title: Prevalence and titers of yellow fever virus neutralizing antibodies in previously vaccinated adults.
abstract: The World Health Organization (WHO) recommends one single dose of the Yellow Fever (YF) vaccine based on studies of antibody persistency in healthy adults. We assessed the prevalence and titers of YF virus neutralizing antibodies in previously vaccinated persons aged  60 years, in comparison to younger adults. We also evaluated the correlation between antibody titers and the time since vaccination among participants who received one vaccine dose, and the seropositivity among participants vaccinated prior to or within the past 10 years.
  previously vaccinated healthy persons aged  18 years were included. YF virus neutralizing antibody titers were determined by means of the 50% Plaque Reduction Neutralization Test.
  46 persons aged  60 years and 48 persons aged 18 to 59 years were enrolled. There was no significant difference in the prevalence of YF virus neutralizing antibodies between the two groups (p = 0.263). However, titers were significantly lower in the elderly (p = 0.022). There was no correlation between YF virus neutralizing antibody titers and the time since vaccination. There was no significant difference in seropositivity among participants vaccinated prior to or within the past 10 years.
  the clinical relevance of the observed difference in YF virus neutralizing antibody titers between the two groups is not clear.
authors.affiliation: Universidade de São Paulo, Faculdade de Medicina, Departamento de Moléstias Infecciosas e Parasitárias, São Paulo, SP, Brazil.
authors.forename: Karina Takesaki
authors.initials: KT
authors.lastname: Miyaji
authors.affiliation: Universidade de São Paulo, Faculdade de Medicina, Departamento de Moléstias Infecciosas e Parasitárias, São Paulo, SP, Brazil.
authors.forename: Vivian Iida
authors.initials: VI
authors.lastname: Avelino-Silva
authors.affiliation: Fundação Oswaldo Cruz, Laboratório de Tecnologia Virológica Bio-Manguinhos, Rio de Janeiro, RJ, Brazil.
authors.forename: Marisol
authors.initials: M
authors.lastname: Simões
authors.affiliation: Fundação Oswaldo Cruz, Laboratório de Tecnologia Virológica Bio-Manguinhos, Rio de Janeiro, RJ, Brazil.
authors.forename: Marcos da Silva
authors.initials: MD
authors.lastname: Freire
authors.affiliation: Instituto Butantan, Hospital Vital Brazil, São Paulo, SP, Brazil.
authors.forename: Carlos Roberto de
authors.initials: CR
authors.lastname: Medeiros
authors.affiliation: Universidade de São Paulo, Faculdade de Medicina, Departamento de Medicina Preventiva, São Paulo, SP, Brazil.
authors.forename: Patrícia Emilia
authors.initials: PE
authors.lastname: Braga
authors.affiliation: Universidade de São Paulo, Faculdade de Medicina, Divisão de Imunologia Clínica e Alergia, São Paulo, SP, Brazil.
authors.forename: Maria Angélica Acalá
authors.initials: MA
authors.lastname: Neves
authors.affiliation: Universidade de São Paulo, Faculdade de Medicina, Departamento de Moléstias Infecciosas e Parasitárias, São Paulo, SP, Brazil.
authors.forename: Marta Heloisa
authors.initials: MH
authors.lastname: Lopes
authors.affiliation: Universidade de São Paulo, Faculdade de Medicina, Divisão de Imunologia Clínica e Alergia, São Paulo, SP, Brazil.
authors.forename: Esper Georges
authors.initials: EG
authors.lastname: Kallas
authors.affiliation: Universidade de São Paulo, Faculdade de Medicina, Departamento de Moléstias Infecciosas e Parasitárias, São Paulo, SP, Brazil.
authors.forename: Ana Marli Christovam
authors.initials: AM
authors.lastname: Sartori
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D057134:Antibodies, Neutralizing / Q000097:blood*; D000914:Antibodies, Viral / Q000097:blood*; D001938:Brazil; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000097:blood; D008297:Male; D008875:Middle Aged; D015004:Yellow Fever / Q000276:immunology / Q000517:prevention & control*; D022341:Yellow Fever Vaccine / Q000276:immunology*; D015005:Yellow fever virus / Q000276:immunology*; D055815:Young Adult
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D007075:Immunoglobulin M; D022341:Yellow Fever Vaccine