Clinical trial to evaluate the safety, reactogenicity and immunogenicity of the vax-TyVi vaccine in volunteers between 18 and 20 years of age.

INTERVENTION: The volunteers were randomly distributed in three groups. They were immunized with the candidate vaccine ‐ vax‐TyVi ‐, or the control vaccines Typhim‐Vi and vax‐TET. A single dose of 0,5 mL by intramuscular route was used. The study vaccine ‐ vax‐TyVi ‐ was developed by Finlay Institute and has 25 ug of purified Salmonella Typhi Vi polysaccharide, without adjuvant, and with a similar composition to other Vi polysaccharide vaccines. Typhoid‐Paratyphoid Vaccines Vax‐TyVi, Typhim‐Vi, Vax‐TET CONDITION: typhoid fever PRIMARY OUTCOME: Objectives: To evaluate safety, reactogenicity and immunogenicity of the typhoid vaccine ‐ vax‐TyVi ‐ in young male and female adults between 18 to 20 years of age, and demonstrating that the immune response elicited by vax‐TyVi is not lower than that induced by the control vaccine Typhim‐Vi. Endpoints: Safety and reactogenicity: 1‐Occurrence of any grade 3 expected symptoms within 7 days following vaccination. 2‐Occurrence of expected local symptoms taking place within 7 days after vaccination. 3‐Occurrence of expected general symptoms taking place within 7 days after vaccination. 4‐Nature, incidence, intensity and relationship to vaccination of unexpected serious adverse events within 30 days after vaccination. 5‐Nature, incidence, intensity and relationship to vaccination of unexpected non‐serious adverse events within 30 days after vaccination. 6‐Incidence of clinically relevant out‐of‐range tests for routine hematology (red blood cells, hemoglobin, hematocrit, leukocytes, differential blood count, platelets), routine microscopic urine examination (red blood cells, leukocytes, epithelial cells), serum creatinine and liver enzymes (aspartate aminotransferase ‐ AST or SGOT, alanine aminotransferase ‐ ALT or SGPT), immediately before and 7 days after vaccination. These laboratory tests were carried out in 33 randomly selected subjects. Immunogenicity: 1‐Anti‐Vi antibody levels were detected by ELISA prior and 21 days after vaccination in all groups. Seroconversion was defined as 2‐fold increase of anti‐Vi antibody titers over pre‐immunization levels. SECONDARY OUTCOME: Not Applicable INCLUSION CRITERIA: 1‐A male or female between, and including, 18 and 20 years of age at the time of the vaccination. 2‐Free from obvious health problems as established by medical history and clinical examination before entering into the study. 3‐Written informed consent obtained from the parents or guardians.