AUTHOR=Campi-Azevedo Ana Carolina , Reis Laise Rodrigues , Peruhype-Magalhães Vanessa , Coelho-dos-Reis Jordana Grazziela , Antonelli Lis Ribeiro , Fonseca Cristina Toscano , Costa-Pereira Christiane , Souza-Fagundes Elaine Maria , Costa-Rocha Ismael Artur da , Mambrini Juliana Vaz de Melo , Lemos Jandira Aparecida Campos , Ribeiro José Geraldo Leite , Caldas Iramaya Rodrigues , Camacho Luiz Antônio Bastos , Maia Maria de Lourdes de Sousa , de Noronha Tatiana Guimarães , de Lima Sheila Maria Barbosa , Simões Marisol , Freire Marcos da Silva , Martins Reinaldo de Menezes , Homma Akira , Tauil Pedro Luiz , Vasconcelos Pedro Fernando Costa , Romano Alessandro Pecego Martins , Domingues Carla Magda , Teixeira-Carvalho Andréa , Martins-Filho Olindo Assis TITLE=Short-Lived Immunity After 17DD Yellow Fever Single Dose Indicates That Booster Vaccination May Be Required to Guarantee Protective Immunity in Children JOURNAL=Frontiers in Immunology VOLUME=10 YEAR=2019 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2019.02192 DOI=10.3389/fimmu.2019.02192 ISSN=1664-3224 ABSTRACT=

The Yellow Fever (YF) vaccination is recommended for people living in endemic areas and represents the most effective strategy to reduce the risk of infection. Previous studies have warned that booster regimens should be considered to guarantee the long-term persistence of 17DD-YF-specific memory components in adults living in areas with YF-virus circulation. Considering the lower seroconversion rates observed in children (9–12 months of age) as compared to adults, this study was designed in order to access the duration of immunity in single-dose vaccinated children in a 10-years cross-sectional time-span. The levels of neutralizing antibodies (PRNT) and the phenotypic/functional memory status of T and B-cells were measured at a baseline, 30–45 days, 1, 2, 4, 7, and 10 years following primary vaccination. The results revealed that a single dose induced 85% of seropositivity at 30–45 days and a progressive time-dependent decrease was observed as early as 2 years and declines toward critical values (below 60%) at time-spans of ≥4-years. Moreover, short-lived YF-specific cellular immunity, mediated by memory T and B-cells was also observed after 4-years. Predicted probability and resultant memory analysis emphasize that correlates of protection (PRNT; effector memory CD8+ T-cells; non-classical memory B-cells) wane to critical values within ≥4-years after primary vaccination. Together, these results clearly demonstrate the decline of 17DD-YF-specific memory response along time in children primarily vaccinated at 9–12 months of age and support the need of booster regimen to guarantee the long-term persistence of memory components for children living in areas with high risk of YF transmission.