Immunity Period After One Dose of Yellow Fever Vaccine in Adults and Children (Paraiba Study)

The study main objective is to assess the immune status of children and adults who have never vaccinated, they will receive the first dose of 17DD yellow fever vaccine provided by the study and will be monitored for 10 years. Depending on the results of the analyzed of the data, the period of monitoring may be extended.

This is a Phase IV study cohort, uncontrolled, composed of two segments: children and healthy adults. It will be included 2756 children and 2005 adults, evaluated initially in six different times (before vaccination, 30-45 days, 1 year, 4 years, 7 years and 10 years after vaccination). The Paraiba state was selected for the study because in this region there are no yellow fever virus dissemination and therefore no NIP recommendation for people's routine vaccination. However, the NIP indicate yellow fever vaccination for individuals who are moving to areas with virus circulation. The study will take place in six (6) Basic Health Units of three (3) municipalities (2 units per municipality) in the state of Paraíba. The selected municipalities are: Alhandra, Caaporã and Conde. The study target population consisted of healthy children and adults of both sexes. Children must be between 9 months and 4 years,11months and 29 days; adults between 18 and 50 years. It will be eligible for the study, people who have never received the yellow fever vaccine checked in vaccine design and history and who agree to participate. Not be included participants with any contraindication to vaccination against yellow fever and individuals who previously moved to risk areas for extended periods.