What to Know About Typhoid Vaccines

Typhoid vaccines are used in children and adults to prevent typhoid fever. Also simply referred to as typhoid, this infectious disease is caused by Salmonella typhi bacteria. It is commonly associated with poor hygiene and public sanitation.

Neither Typhim Vi nor Vivotif, the two typhoid vaccines, are considered routine immunizations for people in the United States. This is because the disease is relatively rare in America.

However, vaccination is recommended for anyone visiting parts of the world where typhoid is endemic, as well as select other individuals. Travelers to these places account for most of the approximate 5,700 cases of typhoid diagnosed in the U.S. each year.

This article provides you with what you need to know about typhoid vaccination, including who should consider it, when to get it, possible side effects, and more.

Uses

Typhoid can lead to high fever, diarrhea, vomiting, pneumonia, encephalitis (inflammation of the brain), and, in some cases, death.

Typhoid vaccines work to protect you from this by stimulating the production of immune cells called antibodies. These cells "recognize" S. typhi if it enters the body and prevent it from establishing an infection.

Typhoid vaccines are only indicated for use in specific populations, namely:

• Travelers to areas where a recognized risk of exposure to typhoid exists
• People who live with or have intimate contact with someone who is a documented S. typhi carrier
• Workers in microbiology labs who handle S. typhi samples

As typhoid vaccines do not fully protect you from this infection, you will still need to take standard precautions to avoid S. typhi at your destination. This includes avoiding untreated drinking water, avoiding raw fruits and vegetables, and washing your hands frequently.

Travel Destinations of Concern

Typhoid vaccination is not required for all international travel but is recommended for those traveling to areas where there is a recognized risk of S. typhi exposure. This includes parts of:

• Africa
• Asia
• Central America
• South America

When planning a trip overseas, check the vaccination requirements and travel advisories for your destination on the CDC traveler's health website.

Typhoid Vaccine Options

Typhim Vi is an inactivated vaccine made with killed S. typhi bacterium. It is delivered by injection.

Vivotif is a live attenuated vaccine made with weakened S. typhi. It is taken orally (by mouth).

Note, though, that Vivotif may not be available to you—at least for now. Its manufacturer temporarily stopped manufacturing this vaccine in December 2020 due to low demand caused by the COVID-19 pandemic.

Neither of the two vaccines is inherently "better" than the other in terms of efficacy. Both offer only partial protection against typhoid fever. But there are some differences that may make one better or more appealing to you than another.

Before Use

If you have a fever or an acute gastrointestinal issue, be sure to postpone Vivotif. This is because it can be difficult to distinguish symptoms you're experiencing because you are sick from side effects of the vaccine. The live vaccine can be used after the illness resolves.

Neither animal nor human studies have not been conducted to assess the safety of Typhim Vi or Vivotif during pregnancy. With that said, the vaccines are classified as Pregnancy Category C drugs, meaning that the benefits of the vaccines may outweigh the potential risks.

Speak with your doctor if you are pregnant, breastfeeding, or planning to get pregnant to make a fully informed choice about typhoid vaccination.

Who Should Not Get a Typhoid Vaccine

There are certain people in whom typhoid vaccines may cause harm and need to be avoided.

Typhim Vi and Vivotif are both contraindicated for use in people who have a history of a severe allergy to any components of the vaccines.

In immunocompromised people, the weakened viruses used in live vaccines have the potential to revert and cause the very diseases they are meant to prevent. This includes people with HIV, organ transplant recipients, people undergoing chemotherapy, and children with primary immunodeficiency (PID).

As a live vaccine, Vivotif may conceivably pose these health risks, although this has not been specifically established. Nevertheless, and as a precaution, Vivotif is not used in people with immunodeficiency.

Dosage

Typhim Vi comes as either as a single-use prefilled syringe or a multi-dose vial.

Vivotif comes as a blister pack of pink-and-white capsules.

The recommended dosage of typhoid vaccines varies by the vaccine type and age.

Revaccination is recommended for international travelers who frequent endemic regions.

• Typhim Vi: Revaccination is recommended every two years.
• Vivotif: Revaccination may only be needed every five years.

How to Take and Store

Typhim Vi is administered by a healthcare professional. The injection is given either to the deltoid muscle of the shoulder or the upper part of the outer thigh (anterolateral thigh).

Vivotif is prescribed and taken at home. It should be taken with a cold or lukewarm drink one hour before eating. Failing to follow these dietary instructions can undermine Vivotif's effectiveness.

Vivotif capsules should not be stored at room temperature. Refrigerate them at temperatures between 35.6 to 46.4 degrees F. Do not freeze the vaccine.

Side Effects

Side effects can occur with both Typhim Vi and Vivotif, although most tend to be mild and resolve on their without treatment.

Side effects are a bit more common with Typhim Vi, affecting as many as one in six users.

The following are the most common side effects for each vaccine with data on the percentage of recipients affected by them:

Severe reactions—including the potentially life-threatening whole-body allergy known as anaphylaxis—are rare with typhoid vaccines.

A 2019 review of studies in the Journal of Allergy and Clinical Immunology reported no cases of anaphylaxis out of 164,483 doses of typhoid vaccine administered.

Interactions

Certain drugs and treatments can interact with Typhim and Vivotif. These include immunosuppressants that blunt the overall immune response and may temper the production of defensive antibodies.

Such drugs include:

• Biologic drugs like Humira (adalimumab) and Xeljanz (tofacitinib)
• Chemotherapy drugs
• Cyclosporine
• High-dose corticosteroids
• Methotrexate
• Radiation therapy

Vivotif can also interact with anti-malaria drugs like Aralen (chloroquine) and Larium (mefloquine), both of which can impair the effectiveness of the vaccine. The interaction appears to be mild, but inform your doctor if you are taking or planning to take anti-malaria drugs before starting Vivotif.