Zyvac Tcv-PFS Vaccine is an active immunizing agent. It is given to prevent typhoid fever caused by certain bacteria called S. Typhi. It is usually administered at least 2 weeks prior to expected exposure to S. Typhi. Zyvac Tcv-PFS Vaccine - Purified Vi Polysaccharide Typhoid Vaccine (25mcg) - Zydus Cadila - Pilcare - Exporter from India to Oman