Booster dose after 10 years is recommended following 17DD-YF primary vaccination

Abstract

A single vaccination of Yellow Fever vaccines is believed to confer life-long protection. In this study, results of vaccinees who received a single dose of 17DD-YF immunization followed over 10 y challenge this premise. YF-neutralizing antibodies, subsets of memory T and B cells as well as cytokine-producing lymphocytes were evaluated in groups of adults before (NVday0) and after (PVday30-45, PVyear1-4, PVyear5-9, PVyear10-11, PVyear12-13) 17DD-YF primary vaccination. YF-neutralizing antibodies decrease significantly from PVyear1-4 to PVyear12-13 as compared to PVday30-45, and the seropositivity rates (PRNT≥2.9Log10mIU/mL) become critical (lower than 90%) beyond PVyear5-9. YF-specific memory phenotypes (effector T-cells and classical B-cells) significantly increase at PVday30-45 as compared to naïve baseline. Moreover, these phenotypes tend to decrease at PVyear10-11 as compared to PVday30-45. Decreasing levels of TNF-α+ and IFN-γ+ produced by CD4+ and CD8+ T-cells along with increasing levels of IL-10+CD4+T-cells were characteristic of anti-YF response over time. Systems biology profiling represented by hierarchic networks revealed that while the naïve baseline is characterized by independent micro-nets, primary vaccinees displayed an imbricate network with essential role of central and effector CD8+ memory T-cell responses. Any putative limitations of this cross-sectional study will certainly be answered by the ongoing longitudinal population-based investigation. Overall, our data support the current Brazilian national immunization policy guidelines that recommend one booster dose 10 y after primary 17DD-YF vaccination.

Recent sylvatic yellow fever virus transmission in Brazil: the news from an old disease

“…A single dose of the YF vaccine is recommended for lifelong protection [39,40], however, this is still an issue of debate. Studies have demonstrated a significant decreasing or even the complete absence of neutralizing antibody titers, effector memory CD4 + and CD8 + T-cells and classical memory B-cells ten years after primary YF vaccination [41][42][43].…”

Urgent call for action: avoiding spread and re-urbanisation of yellow fever in Brazil

“…Due to the sudden increase in demand and limited vaccine supply, the decision by the Ministry of Health to administer only one dose of the vaccine, as recommended by the World Health Organization, was provisionally endorsable. Nevertheless, booster doses are necessary to ensure longer protection for all YFV vaccines ( CGSYF 2014 , Campi-Azevedo et al 2016 ). Therefore, the emergency decision to administer only one dose of the vaccine recently taken by the Brazilian Ministry of Health should be re-evaluated as soon as the current sanitary situation normalises and new information on duration of immunity is available.…”

Single shot of 17D vaccine may not confer life-long protection against yellow fever

“…At least two recent studies in Brazil showed that the level of neutralising antibodies decreases dramatically in adults and children eight and four years after primary vaccination, respectively ( Caldas et al 2014 , Campi-Azevedo et al 2016 ). In addition, between 1980 and 2017, 29 cases of severe and frequently fatal sylvatic YF cases were reported in people previously vaccinated in Brazil, not including cases in the most recent epidemic ( PAHO 2016 ).…”