Typhim Vi

Indications

Typhoid polysaccharide (Vi) vaccine is used to protect adults and children aged 2 years and over against typhoid fever, a serious infection caused by Salmonella Typhi that spreads through contaminated food and water. It is recommended for people living in or travelling to areas where typhoid is common, and for laboratory workers who handle the bacteria.

How It Works

The vaccine contains a purified sugar (Vi polysaccharide) from the outer coat of the typhoid bacterium. It cannot cause typhoid. It trains the immune system to make antibodies against this coat, so if the person is later exposed, the body can fight the infection. Protection develops about 2 to 3 weeks after vaccination and is partial, so food and water hygiene are still important.

Dosage and Administration

The vaccine is given by a doctor, nurse or trained vaccinator as a single injection into a muscle (usually the upper arm), ideally at least 2 weeks before possible exposure. A repeat dose is usually advised every 3 years for people who remain at risk, following the schedule set by the doctor. It is not recommended for children under 2 years, as they do not respond well.

Interactions

It can be given at the same visit as other vaccines, such as hepatitis A, using different injection sites. Medicines that weaken the immune system (such as high-dose steroids or cancer treatment) may reduce the response.

Contraindications

• Severe allergic reaction to a previous dose or to any vaccine ingredient.
• Vaccination should be delayed during a high fever or acute illness; a mild cold is not a reason to delay.

Side Effects

Pain, redness, swelling or hardness at the injection site are common and settle in a day or two. Mild fever, headache, tiredness, muscle aches and nausea may occur. Severe allergic reactions are very rare.

Get urgent medical help for swelling of the face or throat, difficulty breathing, widespread rash or feeling faint after vaccination.

Pregnancy and Lactation

Data in pregnancy are limited; the vaccine is given only if the risk of typhoid is high and the doctor advises it. It may be given during breastfeeding when needed.

Precautions and Warnings

Vaccinated people should be observed for about 15 minutes. Use with care in people with bleeding disorders because of the injection into muscle. The vaccine does not protect against paratyphoid or other causes of food poisoning, so continue safe food and water practices.

Overdose

Overdose is unlikely as it is a single measured dose given by health staff. An extra dose may cause more injection-site soreness.

Therapeutic Class

Vaccine, bacterial polysaccharide (typhoid Vi).

Storage

Store in a refrigerator at 2 to 8°C, do not freeze, protect from light. Keep out of the reach of children.