Immune Response Elicited by Concomitant Administration of Oral Typhoid Fever (Vivotif®) and Cholera (Dukoral®) Vaccines

The goal of this clinical trial is to explore the coadministration of oral typhoid fever (Vivotif®) and cholera (Dukoral®) vaccines in healthy volunteers aged 18-65 years. The main question it aims to answer is: • Does coadministration impact the immune responses to Vivotif® and Dukoral® vaccines Participants will: * receive either oral typhoid fever (Vivotif®) or oral cholera (Dukoral®) vaccines or both simultaneously * give blood samples for immunogenicity analyses * participate in adverse event follow up Researchers will compare those receiving only one of the vaccines to those receiving both simultaneously to see if coadministration has an impact on antigen-specific responses measured with: * ELISPOT (plasmablast responses specific to Salmonella typhi, Vibrio Cholerae and Enterotoxigenic Escherichia coli) * ELISA (antibodies in lymphocyte supernatants (ALS) and serum antibodies specific to vaccine antigens)