Duration of Immunity After Two Doses of Vaccine Against Yellow Fever in Adults

Data Collection Volunteers will be invited to participate by bringing card (s ) vaccination or copy ( s ) of record ( s ) in which it appears ( m) ( s ) dose ( s) received yellow fever vaccine ( s ) and ( s ) their ( s ) date ( s ) . Individuals who agree to participate in the study and signed an Informed Consent Form will be forwarded to interview and application of Inclusion Questionnaire , which will identify possible eligible for the study and classify them according to the time of vaccination. Then a medical review of the history of vaccination with the date or the age in which they occurred , the cities and the period in which he lived and the relevant pathological history , hospitalizations and treatment for chronic diseases will be taken , then proceeding to blood collection.

Upon completion of the subject's participation in the research study , registration must be done at the closing to participate in the study .A group of volunteers previously vaccinated with a dose of yellow fever vaccine and booster having the indicated activity in the areas in which the vaccine is recommended that , constitute a group of 110 patients with different to the search approach, in which a pickup is performed Whole blood for analysis of cellular immune 30-45 days after revaccination.

The clinical forms of the study will be prepared and processed in " TELEform " program , which will enable the digitization and preparation of database.

Sample Size Whereas 98% seropositivity and presence of cellular response after 30 days of revaccination as reference, 110 volunteers will be needed in each group to detect minute differences of 10 percentage points with 80% power and a significance level of 5%.

A total of 440 volunteers with 110 distributed in each group. Samples of 110 individuals will estimate proportions of seropositive up to 50% with precision of 9 percentage points for each side.