Vaccine Interference: Yellow Fever and Cholera Vaccines

Certain vaccines, when administered close together in time, can blunt each other's immune response instead of each producing an independent, adequate response. This phenomenon of vaccine interference is classically described between the Yellow Fever vaccine and the (older, whole-cell) Cholera vaccine.

Why Cholera Vaccine Interferes

• Public health/preventive medicine texts (e.g., Park's Textbook of PSM) note that if the Cholera vaccine is given within 3 weeks before or after the Yellow Fever vaccine, it can reduce the antibody response to the Yellow Fever vaccine.
• Because of this documented interference, international health regulations traditionally recommended spacing these two vaccines at least 3 weeks apart whenever both were required (e.g., for travelers to endemic regions).

Why the Other Options Are Incorrect

• Typhoid vaccine: No significant interference with the Yellow Fever vaccine is described; typhoid vaccination can be co-administered or spaced normally without loss of efficacy for either vaccine.
• Tetanus toxoid: A toxoid (inactivated toxin) vaccine that does not compete immunologically with the live attenuated Yellow Fever vaccine; no interference interval is required.
• Measles vaccine: Although also a live attenuated vaccine, measles vaccine is not classically cited as interfering with Yellow Fever vaccine; in practice, live vaccines like measles and yellow fever can be given together or spaced by the standard 4-week live-vaccine rule, but the specific "3-week interference" teaching point pertains to cholera vaccine, not measles.

Conclusion

Among the given options, the vaccine specifically known to interfere with the Yellow Fever vaccine if administered within 3 weeks is the Cholera vaccine, making Option 1 the correct answer.