Typhoid vaccine is used to prevent typhoid fever. Typhoid fever is caused by the bacterium Salmonella typhi (S. typhi). Typhoid is spread by contaminated water and food. The typhoid vaccine contains a small amount of the typhoid bacteria, enough to stimulate your body to create its own defenses but not enough to cause serious illness. It takes about 2 weeks after injection for the vaccine to begin protecting against typhoid fever.

The typhoid vaccine is recommended for adults and children at least 2 years of age who will be travelling to areas where there is a risk of exposure to S. typhi. In particular, people who will be exposed to potentially contaminated food and water for longer periods of time (more than 4 weeks) should consider receiving this vaccination. It is also recommended for travellers who have reduced or no gastric (stomach) acid secretion, those who live with or have regular contact with someone known to carry S. typhi, and laboratory workers who routinely handle specimens that contain or are believed to contain S. typhi.

The vaccine reduces but does not eliminate the chances of a person getting typhoid fever. Travelers should take all necessary precautions to avoid potentially contaminated sources of food or water. Such precautions include drinking bottled or boiled water and washing hands before eating.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are being given this medication, speak to your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to use this medication if their doctor has not prescribed it.

For adults and children 2 years of age and older, one dose is injected into the outer muscle of the upper arm or the thigh. A qualified health professional will inject the vaccine.

The typhoid vaccine should be given at least 14 days before entering the typhoid risk area for greatest protection from typhoid infection.

A repeat vaccination ("booster") is recommended every 3 years if you repeatedly travel to areas where you are exposed to S. typhi.

The typhoid vaccine may be given at the same time as some other vaccinations as long as they are injected into different areas of the body.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

Store this medication in the refrigerator, do not freeze, protect it from light, and keep it out of the reach of children.

Each 0.5 mL dose of clear, colourless liquid for intramuscular injection contains Salmonella typhi (TY2 strain) Vi polysaccharide 25 µg. Nonmedicinal ingredients: sodium chloride, disodium phosphate dihydrate, sodium dihydrogen phosphate dehydrate, phenol, and water for injection.

Do not take this medication if you:

• are allergic to typhoid vaccine or any ingredients of the medication
• have a fever or severe illness at the time of vaccination

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• diarrhea
• fever
• general body ache or discomfort
• headache
• muscle ache
• nausea
• soreness, pain, redness, or swelling at the injection site

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Seek immediate medical attention if any of the following occur:

• signs of a serious allergic reaction (such as abdominal cramps, difficulty breathing, nausea and vomiting, swelling of the face and throat)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Allergic reactions: Rarely, this vaccine may cause severe allergic reactions. If you notice the signs of a severe allergic reaction (hives; trouble breathing or swallowing; or swelling of the lips, face, throat, or tongue) get medical attention immediately.

Bleeding problems: If you have blood clotting problems or are currently taking blood thinners (oral anticoagulants), notify your doctor before your injection.

Immunocompromised people: Typhoid vaccine may not be as effective for people with a compromised immune system (e.g., people with AIDS, people receiving chemotherapy, or people taking any medication that suppresses the immune system). People with any of these conditions should discuss with their doctor how this medication may affect their medical condition, how their medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Infection and fever: Delay receiving the typhoid vaccine if you have an infection or fever, unless, in the opinion of your doctor, the benefits of receiving the vaccine while you are ill outweigh the risks.

Protection against typhoid: Not all people who take the vaccine will be fully protected against typhoid. This is especially true for those who receive the vaccine less than 2 weeks before arriving in the areas with typhoid exposure risk.

Pregnancy: The effects of this medication on an unborn baby are not known. This medication should not be used during pregnancy unless the benefits outweigh the risks. If you are or may be pregnant, discuss the risks and benefits of using this vaccine with your doctor.

Breast feeding: It is not known if typhoid vaccine passes into breast milk. If you are breast-feeding and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children under 2 years of age.

There may be an interaction between typhoid vaccine and any of the following:

• antineoplastic or chemotherapy medications
• corticosteroids (e.g., dexamethasone, prednisone)
• immunosuppressants (e.g., azathioprine, cyclosporine, dupilumab, fingolimod, hydroxychloroquine, leflunomide, ocrelizumab, tacrolimus)
• other live vaccines

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.