title: Persistence of Rabies Virus-Neutralizing Antibodies after Vaccination of Rural Population following Vampire Bat Rabies Outbreak in Brazil.
abstract: BACKGROUND
  Animal control measures in Latin America have decreased the incidence of urban human rabies transmitted by dogs and cats; currently most cases of human rabies are transmitted by bats. In 2004-2005, rabies outbreaks in populations living in rural Brazil prompted widespread vaccination of exposed and at-risk populations. More than 3,500 inhabitants of Augusto Correa (Pará State) received either post-exposure (PEP) or pre-exposure (PrEP) prophylaxis. This study evaluated the persistence of rabies virus-neutralizing antibodies (RVNA) annually for 4 years post-vaccination. The aim was to evaluate the impact of rabies PrEP and PEP in a population at risk living in a rural setting to help improve management of vampire bat exposure and provide additional data on the need for booster vaccination against rabies.
  
  
  RESULTS
  This prospective study was conducted in 2007 through 2009 in a population previously vaccinated in 2005; study participants were followed-up annually. An RVNA titer >0.5 International Units (IU)/mL was chosen as the threshold of seroconversion. Participants with titers ≤0.5 IU/mL or Equivalent Units (EU)/mL at enrollment or at subsequent annual visits received booster doses of purified Vero cell rabies vaccine (PVRV). Adherence of the participants from this Amazonian community to the study protocol was excellent, with 428 of the 509 (84%) who attended the first interview in 2007 returning for the final visit in 2009. The long-term RVNA persistence was good, with 85-88.0% of the non-boosted participants evaluated at each yearly follow-up visit remaining seroconverted. Similar RVNA persistence profiles were observed in participants originally given PEP or PrEP in 2005, and the GMT of the study population remained >1 IU/mL 4 years after vaccination. At the end of the study, 51 subjects (11.9% of the interviewed population) had received at least one dose of booster since their vaccination in 2005.
  
  
  CONCLUSIONS
  This study and the events preceding it underscore the need for the health authorities in rabies enzootic countries to decide on the best strategies and timing for the introduction of routine rabies PrEP vaccination in affected areas.
authors.affiliation: Universidade Federal do Pará e Instituto Evandro Chagas, Belém-Pará, Brasil.
authors.forename: Rita
authors.initials: R
authors.lastname: Medeiros
authors.affiliation: Sanofi Pasteur, France.
authors.forename: Viviane
authors.initials: V
authors.lastname: Jusot
authors.affiliation: Sanofi Pasteur, France.
authors.forename: Guy
authors.initials: G
authors.lastname: Houillon
authors.affiliation: Sanofi Pasteur, France.
authors.forename: Anvar
authors.initials: A
authors.lastname: Rasuli
authors.affiliation: Centro de Controle de Zoonoses, Sao-Paulo, Brasil.
authors.forename: Luzia
authors.initials: L
authors.lastname: Martorelli
authors.affiliation: Centro de Controle de Zoonoses, Sao-Paulo, Brasil.
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Kataoka
authors.affiliation: Institut Pasteur, Paris, France.
authors.forename: Mohamed Ben
authors.initials: MB
authors.lastname: Mechlia
authors.affiliation: Institut Pasteur, Paris, France.
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Le Guern
authors.affiliation: Universidade Federal do Pará e Instituto Evandro Chagas, Belém-Pará, Brasil.
authors.forename: Liliam
authors.initials: L
authors.lastname: Rodrigues
authors.affiliation: Universidade Federal do Pará e Instituto Evandro Chagas, Belém-Pará, Brasil.
authors.forename: Rhomero
authors.initials: R
authors.lastname: Assef
authors.affiliation: Universidade Federal do Pará e Instituto Evandro Chagas, Belém-Pará, Brasil.
authors.forename: Alvino
authors.initials: A
authors.lastname: Maestri
authors.affiliation: Secretaria de Saude do Estado do Pará, Brasil.
authors.forename: Reynaldo
authors.initials: R
authors.lastname: Lima
authors.affiliation: Institut Pasteur, Paris, France.
authors.forename: Yolande
authors.initials: Y
authors.lastname: Rotivel
authors.affiliation: Sanofi Pasteur, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Bosch-Castells
authors.affiliation: Institut Pasteur, Paris, France.|Secretaria de Saude do Estado do Pará, Brasil.|Institut Pasteur de Guinée, Gamal Abdel Nasser University, Conakry, Guinea.
authors.forename: Noël
authors.initials: N
authors.lastname: Tordo