How Often Do You Need to Get a Typhoid Vaccine?

How often you need a typhoid vaccine depends on which of the three available types you receive. The injectable polysaccharide vaccine calls for a booster every two years if you remain at risk. The oral live vaccine requires revaccination every five years. And the newer conjugate vaccines, now rolling out in many countries, appear to hold up for at least five years on a single dose, though researchers are still working out whether a booster will eventually be needed. The schedules are different because the vaccines work differently, and understanding those differences helps you figure out what actually applies to your situation.

Three Vaccines, Three Schedules

There are currently three categories of licensed typhoid vaccine, and each one comes with its own timing.

Oral live vaccine (Ty21a): Sold under the brand name Vivotif, this is a series of four capsules taken every other day over a week. If you continue traveling to or living in areas where typhoid is common, you take the full course again every five years.
Injectable polysaccharide vaccine (Vi-PS): A single shot that uses a piece of the bacterium’s sugar coating. If ongoing risk continues, you get a booster shot every two years.
Typhoid conjugate vaccine (TCV): A single injection that links the same sugar coating to a protein carrier, producing a stronger immune response. The World Health Organization recommended TCVs for routine use in 2018, and several countries have since added them to childhood immunization programs.¹ Current evidence suggests protection lasts at least five years, with the question of boosters still under active study.

The oral and polysaccharide vaccines have been in use since the late 1980s and early 1990s, replacing older whole-cell injections that caused considerably more side effects.² The conjugate vaccines are the newest addition and are changing the conversation about booster timing.

How Well Each Vaccine Protects You

No typhoid vaccine is a guarantee. A large meta-analysis pooling data from trials in typhoid-endemic countries found that the oral vaccine (Ty21a) reduced typhoid cases by about 45 percent, while the polysaccharide shot (Vi-PS) reduced them by about 58 percent.³ Those numbers may sound modest, but they represent protection in settings with heavy ongoing exposure. For a traveler visiting an endemic area for a few weeks, the practical benefit is higher because exposure is more limited.

The conjugate vaccines perform substantially better. The same meta-analysis found that a single dose of TCV was about 83 percent effective at two years post-vaccination, pooled across four trials involving over 100,000 participants.³ A phase 2b trial comparing Vi-TT (a specific conjugate) head-to-head with Vi-PS found that every single participant in the conjugate group developed a strong antibody response, versus about 89 percent in the polysaccharide group, with the conjugate producing antibody levels roughly four times higher.⁴

A study of U.S. travelers estimated that typhoid vaccination within the previous five years was about 80 percent effective at preventing confirmed typhoid fever.⁵ That real-world figure is encouraging, but it also highlights a gap: only a small fraction of travelers who developed typhoid had actually been vaccinated, suggesting that many people either skip the vaccine entirely or let their boosters lapse.

Why the Polysaccharide Vaccine Needs More Frequent Boosters

The polysaccharide vaccine (Vi-PS) works by exposing your immune system to the Vi sugar coating of the typhoid bacterium. Your body produces antibodies against it, but because the sugar alone does not engage the deeper arm of your immune system that builds long-term memory, antibody levels drop off relatively quickly. The original trial that established the Vi-PS vaccine’s usefulness found roughly 60 percent protection over 21 months of follow-up after a single injection.⁶ Protection at three years sits around 55 percent and is considered reliable for at least three years, after which it fades enough that public health guidelines recommend revaccination every two years for people who remain at risk.⁷

The oral vaccine (Ty21a) fares somewhat better on durability, with protection estimated to last at least five to seven years.⁷ Because it is a live, weakened bacterium taken by mouth, it stimulates a broader immune response in the gut, which seems to produce somewhat longer-lasting protection even though its overall efficacy is slightly lower.

How Long Do Conjugate Vaccines Last

This is the question researchers are most actively trying to answer. Conjugate vaccines link the Vi sugar to a protein, and that combination recruits your immune system’s memory cells far more effectively than the sugar alone.⁸ The result is higher antibody levels that persist longer.

A follow-up study of the conjugate vaccine Typbar-TCV tracked children for seven years after their primary vaccination. In children who received a booster around age two, antibody levels stayed well above baseline through the full seven years, with over 70 percent still showing strong seroconversion at that point. Even unboosted children maintained detectable antibody rises, though the gap between boosted and unboosted groups widened over time. The study’s authors suggested that a booster around five years after the initial dose, timed to coincide with school entry, could be a practical strategy to extend protection.⁹

A 2025 expert review echoed this, noting that while conjugate vaccines are effective, immunity appears to wane after five years, particularly in children vaccinated before age two. The authors argued that the current single-dose schedule may need revision, with options including either raising the age of the first dose or adding a booster at school entry.¹⁰ For travelers and adults, the practical takeaway is that a conjugate vaccine likely holds up for at least five years and possibly longer, but firm booster recommendations for adults have not yet been standardized globally.

Who Needs a Typhoid Vaccine in the First Place

Typhoid fever is caused by the bacterium Salmonella Typhi and spreads through contaminated food and water. It remains most common in parts of South Asia, Southeast Asia, and sub-Saharan Africa, where clean water infrastructure and sanitation are limited.¹¹ Bangladesh, India, and Pakistan consistently report the highest burden.

Vaccination is recommended for travelers heading to endemic regions, people visiting friends and relatives in those areas, and laboratory workers who handle the bacterium. If you are a tourist spending two weeks in Southeast Asia, you probably need one dose of whichever vaccine is available to you before departure (ideally at least two weeks ahead). If you are an aid worker or expatriate living in an endemic region for years, the booster schedule described above applies and is worth tracking carefully.

The people at highest risk of letting their boosters slip are long-term residents and repeat travelers who got vaccinated once, years ago, and assumed they were covered indefinitely. They are not.

Having Had Typhoid Does Not Mean You Are Protected

A common assumption is that surviving typhoid fever leaves you immune. The evidence suggests otherwise. A study in Kolkata tracked residents over several years and found that people who had already had a confirmed episode of typhoid were not protected against getting it again. In fact, those with a documented first episode were roughly twice as likely to have a subsequent typhoid visit compared to people who had never been diagnosed, after adjusting for other risk factors.¹² The reasons are not entirely clear but may involve ongoing exposure in endemic settings and the bacterium’s ability to evade natural immune memory. Regardless, a past infection is not a substitute for vaccination.

Drug-Resistant Typhoid Makes Vaccination More Urgent

One of the strongest arguments for staying current on typhoid vaccination is the rise of drug-resistant strains. Extensively drug-resistant (XDR) typhoid, which resists all but one or two oral antibiotics, emerged in Pakistan in 2016 and has been spreading. Pakistan became the first country to introduce TCV into its national immunization program partly in response to this crisis, and early data from that setting showed the conjugate vaccine was 97 percent effective against XDR strains.¹³ Zimbabwe followed with its own TCV rollout after a large drug-resistant outbreak.

Multi-drug resistant strains are also a growing concern across Africa, prompting calls for faster adoption of conjugate vaccines on the continent.¹⁴ For travelers, the implication is straightforward: if you catch a resistant strain, treatment is harder and more expensive. Prevention through vaccination becomes more valuable as treatment options narrow.

Combined Vaccines for Travelers

If you are headed somewhere with typhoid risk, there is a good chance hepatitis A is also a concern, since both diseases spread through contaminated food and water. Combined vaccines that deliver typhoid polysaccharide and hepatitis A in a single injection exist and have been tested in clinical trials. One trial found that a combined vaccine (Vivaxim) produced strong antibody responses to both components in adults already primed with hepatitis A vaccine.¹⁵ Another comparison found that different combined formulations varied in how quickly and strongly they triggered antibodies, but both achieved protective levels for the two diseases.¹⁶

If you are visiting a travel clinic and need both vaccines anyway, a combination product saves you a needle. Keep in mind that the typhoid component of these combination vaccines is the polysaccharide type, so the two-year booster schedule still applies for the typhoid portion. The hepatitis A component follows its own schedule, typically requiring a booster six to twelve months after the initial dose for long-lasting protection.

Storage Challenges and What They Mean for Potency

Typhoid vaccines, like most vaccines, are designed to be stored in a cold chain, typically between 2 and 8 degrees Celsius. This matters more than you might think, because many of the places with the highest typhoid burden also have the least reliable refrigeration infrastructure. If a vaccine loses potency during shipping or storage, its protection drops even if the schedule is followed correctly.

Research into heat stability has been encouraging on this front. A stabilized version of the oral Ty21a vaccine formulated with specific protective compounds showed no loss of potency after 12 weeks stored at standard refrigerator and room temperature, and retained useful potency even at body temperature for the same period.¹⁷ For the conjugate vaccine Typbar-TCV, extended stability testing showed that the vaccine’s structure held up well even at elevated temperatures for prolonged periods, supporting the possibility of short-term use outside the cold chain during mass vaccination campaigns.¹⁸

For a traveler getting vaccinated at a clinic in a high-income country, cold chain integrity is rarely a personal worry. But if you are receiving a vaccine during a mass campaign in a rural area, the improved heat stability of newer formulations is a meaningful reassurance that the dose you receive will actually work as expected, and that sticking to the recommended booster interval makes sense rather than guessing you need to come back sooner.

Practical Booster Timing for Repeat Travelers

If you travel to endemic areas regularly, the simplest approach is to anchor your booster schedule to the type of vaccine you received. For the injectable polysaccharide, mark your calendar for two years. For the oral vaccine, five years. If you received a conjugate vaccine, five years is a reasonable working interval based on current data, though you should check for updated guidance from your country’s health authority, since recommendations for TCV boosters in travelers are still evolving.

One thing to avoid is assuming that food and water precautions alone will protect you without vaccination. They help, but typhoid transmission in endemic areas can be subtle. Contaminated water used to wash vegetables, ice made from untreated sources, or street food prepared by an asymptomatic carrier can all transmit the bacterium. Vaccination is a layer of protection that works even when your precautions fail. And because no typhoid vaccine is 100 percent effective, careful hygiene practices remain worthwhile even when your vaccination is current.

If you are unsure whether your last typhoid vaccine is still within its window, a travel clinic can advise you. In most cases, revaccination is straightforward and carries minimal side effects. There is no penalty for getting a booster slightly early if your next trip falls a few months before your scheduled interval is up.