Typhoid and Leptospirosis Prophylaxis
Introduction to Prophylaxis
- The Centers for Disease Control and Prevention recommends typhoid vaccination for travelers to endemic areas, laboratory workers, and household contacts of documented typhoid carriers, with two widely available vaccines offering 50-80% protection: the oral live-attenuated Ty21a vaccine and the injectable Vi polysaccharide vaccine 1, 2
Typhoid Prophylaxis
- The American College of Physicians recommends vaccination for adults and children ≥6 years, with the oral Ty21a vaccine administered as one enteric-coated capsule taken on alternate days for a total of four capsules, and the injectable Vi polysaccharide vaccine administered as a single 0.5 mL dose for adults and children ≥10 years 3
- The Centers for Disease Control and Prevention recommends revaccination with the entire four-dose series every 5 years for the oral Ty21a vaccine, and every 2-3 years under conditions of continued or repeated exposure for the injectable Vi polysaccharide vaccine 1, 3
- The World Health Organization notes that vaccination is not a substitute for careful food and water selection, as vaccines are not 100% effective and protection can be overwhelmed by large bacterial inocula 3, 4
Leptospirosis Prophylaxis
- The Centers for Disease Control and Prevention recommends primary prevention measures, including avoiding exposure to contaminated water and soil, using protective clothing and footwear, and controlling rodent populations in residential and occupational settings 2, 3
- The National Institute for Occupational Safety and Health recommends antibiotic chemoprophylaxis with doxycycline 200 mg orally once weekly for high-risk exposures, though this is based on limited evidence and is not routinely recommended for travelers 3
- The World Health Organization notes that prophylaxis does not replace the need for prompt medical evaluation if symptoms develop after potential exposure, and the decision to use antibiotic prophylaxis must weigh the risk of exposure against potential adverse effects and the development of antibiotic resistance 4