Typhoid vaccine (Patient information)

# Vaccine
Two typhoid vaccines are currently available in the United States: an oral live, attenuated vaccine (Vivotif Berna vaccine, manufactured from the Ty21a strain of S. Typhi by the Swiss Serum and Vaccine Institute) and a Vi capsular polysaccharide vaccine (ViCPS) (Typhim Vi, manufactured by sanofi pasteur) for intramuscular use. Both vaccines protect 50%-80% of recipients. The intramuscular heat-phenol-inactivated vaccine (manufactured by Wyeth-Ayerst) was discontinued in 2000. Combined hepatitis A/typhoid fever vaccines are not licensed in the United States, but may be available in other countries. The time required for primary vaccination differs for the two vaccines, as do the lower age limits.
Primary vaccination with oral Ty21a vaccine consists of four capsules, one taken every other day. The capsules should be kept refrigerated (not frozen), and all four doses must be taken to achieve maximum efficacy. Each capsule should be taken with cool liquid no warmer than 37 C (98.6 F), approximately 1 hour before a meal. This regimen should be completed 1 week before potential exposure. The vaccine manufacturer recommends that Ty21a not be administered to infants or children younger than 6 years of age.
Primary vaccination with ViCPS consists of one 0.5-mL (25-g) dose administered intramuscularly. One dose of this vac-cine should be given at least 2 weeks before expected exposure. The manufacturer does not recommend the vaccine for infants and children younger than 2 years of age.

## Adverse Reactions
Information on adverse reactions is presented in Table 4-22. Information is not available on the safety of these vaccines in pregnancy; it is prudent on theoretical grounds to avoid vaccinating pregnant women. Live, attenuated Ty21a vaccine should not be given to immunocompromised travelers, including those infected with HIV. The intramuscular vaccine presents a theoretically safer alternative for this group. The only contraindication to vaccination with ViCPS vaccine is a history of severe local or systemic reactions after a previous dose. Neither of the available vaccines should be given to persons with an acute febrile illness.

## Precautions and Contraindications
Theoretical concerns have been raised about the immunogenicity of live, attenuated Ty21a vaccine in persons concurrently receiving antibiotics, immune globulin, or viral vaccines. The growth of the live Ty21a strain is inhibited in vitro by various antibacterial agents. Vaccination with Ty21a should be delayed for >24 hours after the administration of any antibacterial agent. Available data do not suggest that simultaneous administration of oral polio or yellow fever vaccine decreases the immunogenicity of Ty21a. If typhoid vaccination is warranted, it should not be delayed because of administration of viral vaccines. Simultaneous administration of Ty21a and immune globulin does not appear to pose a problem.

# What You Need to Know?

# 1. What is typhoid?
Typhoid (typhoid fever) is a serious disease.  It is caused by bacteria called Salmonella Typhi.
Typhoid causes a high fever, weakness, stomach pains, headache, loss of appetite, and sometimes a rash.  If it is not treated, it can kill up to 30% of people who get it.
Some people who get typhoid become carriers, who can spread the disease to others.
Generally, people get typhoid from contaminated food or water.  Typhoid is not common in the U.S., and most U.S. citizens who get the disease get it while traveling.  Typhoid strikes about 21 million people a year around the world and kills about 200,000.
Typhoid vaccine can prevent typhoid.

# 2. Typhoid vaccines
There are two vaccines to prevent typhoid.  One is an inactivated (killed) vaccine gotten as a shot, and the other is live, attenuated (weakened) vaccine which is taken orally (by mouth).

# 3. Who should get typhoid vaccine and when?
Routine typhoid vaccination is not recommended in the United States, but typhoid vaccine is recommended for:
- Travelers to parts of the world where typhoid is common. (NOTE: typhoid vaccine is not 100% effective and is not a substitute for being careful about what you eat or drink.)
- People in close contact with a typhoid carrier.
- Laboratory workers who work with Salmonella Typhi bacteria.

## Inactivated Typhoid Vaccine (Shot)
- Should not be given to children younger than 2 years of age.
- One dose provides protection.  It should be given at least 2 weeks before travel to allow the vaccine time to work.
- A booster dose is needed every 2 years for people who remain at risk.

## Live Typhoid Vaccine (Oral)
- Should not be given to children younger than 6 years of age.
- Four doses, given 2 days apart, are needed for protection. The last dose should be given at least 1 week before travel to allow the vaccine time to work.
- A booster dose is needed every 5 years for people who remain at risk.
Either vaccine may be given at the same time as other vaccines.

# 4. Some people should not get typhoid vaccine or should wait.

## Inactivated Typhoid Vaccine (Shot)
- Anyone who has had a severe reaction to a previous dose of this vaccine should not get another dose.

## Live Typhoid Vaccine (Oral)
- Anyone who has had a severe reaction to a previous dose of this vaccine should not get 		another dose.
- Anyone whose immune system is weakened should not get this vaccine.  They should get the inactivated typhoid vaccine instead.  These people include anyone who:
- Has HIV/AIDS or another disease that affects the immune system.
- Is being treated with drugs that affect the immune system, such as steroids, for 2 weeks or longer.
- Has any kind of cancer.
- Is taking cancer treatment with x-rays or drugs.
- Oral typhoid vaccine should not be given within 24 hours of certain antibiotics.
Ask your doctor or nurse for more information.

# 5. What are the risks from typhoid vaccine?
A vaccine, like any medicine, could possibly cause serious problems, such as severe allergic reactions.  The risk of a vaccine causing serious harm, or death, is extremely small. Serious problems from either of the two typhoid vaccines are very rare.

## Inactivated Typhoid Vaccine (Shot)

### Mild Reactions
- Fever (up to about 1 person per 100).
- Headache (up to about 3 people per 100).
- Redness or swelling at the site of the injection (up to 7 people per 100).

## Live Typhoid Vaccine (Oral)

### Mild Reactions
- Fever or headache (up to about 5 people per 100).
- Abdominal discomfort, nausea, vomiting, or rash 	(rare).

# 6. What if there is a moderate or severe reaction?

## What should I look for?
- Any unusual condition, such as a high fever or behavior changes. Signs of a serious allergic reaction can include difficulty breathing, hoarseness or wheezing, hives, paleness, weakness, a fast heart beat or dizziness.

## What should I do?
- Call a doctor, or get the person to a doctor right away.
- Tell your doctor what happened, the date and time it happened, and when the vaccination was given.
- Ask your doctor, nurse, or health department to report the reaction by filing a Vaccine Adverse Event Reporting System (VAERS) form.
- Or you can file a report through the VAERS web site at www.vaers.org, or by calling 1-800-822-7967.

# 7. How can I learn more?
- Ask your doctor or nurse. They can give you the vaccine package insert or suggest other sources of information.
- Call your local or state health department.
- Contact the Centers for Disease Control and Prevention (CDC):
- Call 1-800-232-2522 (English)
- Call 1-800-232-0233 (Espanol)
- Visit CDCs typhoid website at 

# Sources
- Department of Health and Human Services Centers for Disease Control and Prevention
National Immunization Program