A 2009 clinical trial of response dose of the yellow fever vaccine (17DD) produced by the Instituto de Tecnologia em Imunobiológicos (Bio-Manguinhos/Fiocruz) was carried out to analyze the application of doses to their patients, in decreasing order.
The results showed that the vaccine can be used in doses much lower than the one normally used, and displayed satisfactory results regarding immunity 10 months after the first vaccination.
This piece of information is crucial so that the recommendation of ordinary use of fractional doses can be implemented on children and adults, and is of great interest for the World Health Organization (WHO).
Taking this into account, the current project aims to verify whether the duration of the immunity induced by lower doses is long lasting, as there are no previous studies with fractional doses evaluating the immunological profile after vaccination. This would provide new information that may help with the use of fractional doses in adults.