The typhoid vaccine plays a crucial role in protecting individuals from the bacterial infection known as typhoid fever. There are two primary types of typhoid vaccines: the oral typhoid vaccine and the injectable typhoid vaccine. In this blog post, we will explore the duration of protection provided by each vaccine and discuss the factors that can influence their effectiveness over time.
Table: Duration of typhoid vaccine before needing to get it again
When to take it
Inactivated typhoid vaccine
Oral (4 pills taken every other day for 1 week)
Start taking it 2 weeks before travel
Every 2 years
Live typhoid vaccine
At least 2 weeks before travel
Every 5 years
Oral Typhoid Vaccine
The oral typhoid vaccine, also known as the Ty21a vaccine, is administered through an oral capsule. It is a live attenuated vaccine that stimulates the immune system to develop protection against Salmonella Typhi, the bacteria that cause typhoid fever.
Duration of Protection: The oral typhoid vaccine provides protection for several years. Studies have shown that it can provide immunity for at least three years after completing the recommended dosing schedule. However, research suggests that the immunity may last even longer, with some individuals retaining protection for up to five to seven years or more.
Booster Doses: As the protection offered by the oral typhoid vaccine can gradually decline over time, booster doses may be required to maintain immunity. The need for boosters can vary depending on factors such as individual risk factors, travel plans to typhoid-endemic regions, and the duration since the initial vaccination series. Consulting with a healthcare professional can help determine the need for booster doses based on specific circumstances.
Injectable Typhoid Vaccine
The injectable typhoid vaccine, also known as the Vi polysaccharide vaccine or the Vi conjugate vaccine, is administered as an injection. It contains a purified component of the Salmonella Typhi bacteria and stimulates the immune system to develop protection against typhoid.
Duration of Protection: The injectable typhoid vaccine offers protection for a significant period. Studies indicate that the Vi polysaccharide vaccine provides immunity for approximately two to three years after the initial vaccination. The newer Vi conjugate vaccine has shown extended duration of protection, with studies suggesting immunity for up to five years or more.
Booster Doses: Similar to the oral typhoid vaccine, booster doses may be necessary for the injectable typhoid vaccine to maintain long-term immunity. The need for booster doses depends on individual risk factors, travel plans, and the duration since the initial vaccination. Healthcare professionals can provide guidance on when and if booster doses are recommended.
Both the oral and injectable typhoid vaccines are effective in providing protection against typhoid fever. While the exact duration of immunity can vary among individuals, the injectable vaccine typically offers protection for several years, while the oral vaccine can provide immunity for a similar duration or longer. It is important to note that the efficacy of these vaccines does gradually decline over time, and booster doses may be required, especially for individuals with ongoing exposure to typhoid or those planning to travel to typhoid-endemic regions.
Consulting with a travel health professional is crucial to determine the appropriate vaccination schedule and the need for booster doses based on individual circumstances. By staying informed and maintaining up-to-date vaccination, individuals can safeguard themselves against typhoid and contribute to the overall reduction of this preventable disease.