Typhoid Vaccine

What is Typhoid fever?

Typhoid fever, also called enteric fever, is an infection caused by the Salmonella Typhi bacteria. It is most common in parts of Southeast Asia, the Eastern Mediterranean, Africa, and the Caribbean. Another similar condition, paratyphoid fever, is caused by Salmonella Paratyphi, which often produces milder symptoms.

The bacteria is spread mainly through the faecal–oral route, with the common sources of infection including:

• Contaminated food or water
• Flies carrying the bacteria
• Contact with contaminated surfaces or utensils
• Poor hygiene or handwashing practices

While typhoid fever can be treated with antibiotics, prevention through vaccination and good hygiene remains the best protection.

What are the symptoms of Typhoid fever?

Some of the symptoms of the disease may include:

• Abdominal pain
• Fever and chills
• Diarrhoea or constipation
• Headaches
• Loss of appetite
• Muscle aches
• Nausea and vomiting
• Rash (known as “rose spots”)

How does the Typhoid Vaccine work?

The typhoid vaccine is designed to train the immune system to recognise and fight off infections caused by Salmonella Typhi. It contains a harmless, non-infectious part of the bacteria, the Vi polysaccharide antigen, which cannot cause illness but stimulates the body to develop immunity against future infections.

When you receive the typhoid vaccine, the antigen in the vaccine triggers an immune response. The body produces specific antibodies that target S. Typhi, allowing the immune system to quickly recognise and neutralise the bacteria if you are exposed in the future. This process helps prevent severe illness and reduces the risk of complications, even if infection still occurs.

In Singapore, there is one main typhoid vaccine available:

• Typhim Vi (Polysaccharide Vaccine) — contains the purified Vi polysaccharide antigen from S. Typhi. It is suitable for adults and children aged 2 years and older and is given as a single injection at least 2 weeks before potential exposure.

The Typhim Vi vaccine mimics the protective effect of natural exposure without causing illness, allowing the body to build strong, lasting immunity while avoiding the risks of actual typhoid fever.

Protection is strongest in the first 2 to 3 years after vaccination, which is why booster doses are recommended if you remain at risk.

What are the benefits of the Typhoid Vaccine?

Typhoid vaccination is the most effective way to protect against typhoid fever caused by Salmonella Typhi. It significantly reduces the risk of severe illness, complications, and the spread of infection in high-risk settings.

Some of the key benefits of getting vaccinated are:

• Prevents severe illness — lowers the risk of developing high fever, abdominal pain, and prolonged weakness associated with typhoid fever.
• Reduces hospital admissions — vaccinated individuals are far less likely to require hospitalisation for complications.
• Prevents serious complications — protects against life-threatening issues such as gastrointestinal bleeding, intestinal perforation, encephalopathy, hepatitis, and kidney failure.
• Provides early protection — recommended before travel to typhoid-endemic regions or for those in close contact with carriers.
• Reduces the spread of infection — helps limit transmission in communities and households.
• Safe and well-tolerated — extensively tested and recommended by global and national health authorities.
• Long-lasting immunity — protection typically lasts up to three years, with booster doses available if ongoing exposure risk remains.

Why is it important to get the Typhoid Vaccine?

Vaccination is particularly important if you:

• Are travelling to typhoid-endemic regions
• Live with or have close contact with a known typhoid carrier
• Work in microbiology laboratories handling S. Typhi

Who should get the Typhoid Vaccine?

Vaccination provides strong protection for those at higher risk of exposure to S. Typhi. It is most recommended for:

• Travellers to endemic regions — including parts of Southeast Asia, Africa, and the Caribbean.
• People living with or in close contact with a carrier — reduces the risk of contracting the infection at home.
• Laboratory workers — especially those handling S. Typhi in microbiology labs.

A booster dose is also advised every three years if you remain at risk. Even after vaccination, you should continue practising safe food and water habits, as the vaccine is not 100% effective.

Who should not get the Typhoid Vaccine?

While the typhoid vaccine is safe and effective for most adults and children aged two years and older, there are certain situations where it may not be suitable. You should consult a doctor before vaccination if you:

Should not receive the vaccine:

• Have had a severe allergic reaction (anaphylaxis) to a previous typhoid vaccine or any of its components
• Are immunocompromised due to a medical condition or treatment
• Have an acute illness or high fever (vaccination should be postponed)
• Are pregnant or breastfeeding, unless advised by a doctor

May need to delay vaccination:

• Are currently unwell with moderate or severe illness
• Have temporary immune suppression, such as during certain medical treatments

What are the possible side effects?

Most side effects are mild and temporary, including:

• Pain, redness, or swelling at the injection site
• Mild fever

Rarely, severe allergic reactions may occur, with symptoms such as:

• Swelling of the face, lips, or tongue
• Difficulty breathing or chest tightness
• Generalised rash or hives

These reactions require immediate medical attention, as they may signal anaphylaxis.

How do I know if I am a typhoid carrier?

A typhoid carrier has S. Typhi in their body but does not show symptoms, yet can still spread the bacteria to others. Carriers shed the bacteria in their faeces, sometimes for over a year. As such, diagnosis is made through stool testing.

About 5% of infected people become chronic carriers. The vaccine is not used for treatment and is not recommended for those currently infected.

What to expect from receiving the Typhoid Vaccine?

Knowing what to expect before, during, and after vaccination can help you prepare and ensure a smooth experience.

Before vaccination

Our doctor will perform a quick health check to confirm the vaccine is safe and appropriate. This includes:

• Review of medical history and allergies
• Check for fever or acute illness
• Assessment of immune status and current treatments
• Discussion about pregnancy or breastfeeding
• For travellers, schedule vaccination at least 2 weeks before departure

During vaccination

The process is quick and straightforward, with minimal discomfort. It entails the following:

• Given as a single injection, usually into the upper arm
• Mild stinging or pressure at the injection site
• Brief explanation from our doctor
• Short observation period (15 to 30 minutes) to monitor rare immediate reactions

After vaccination

Most people resume normal activities right away. Although mild and temporary side effects may occur, they typically resolve within 1 to 2 days. During this time, it is best to use a cool compress and keep the arm mobile to reduce soreness.

Meanwhile, do seek urgent medical attention for:

• Difficulty breathing
• Swelling of face, lips, or tongue
• Widespread rash or hives
• Persistent high fever

It is important to continue to practice safe food and water habits post-vaccination, as no vaccine provides complete protection.

Summary

Typhoid fever can cause serious illness and disrupt travel plans, with complications including hepatitis, kidney failure, and intestinal perforation. The typhoid vaccine is a safe and effective way to reduce your risk.

At Phoenix Medical Group, we offer the Typhim Vi typhoid vaccine for adults and children from 2 years old. If you are travelling to an at-risk area or living with a known carrier, protect yourself and your loved ones by booking your vaccination today.

Frequently Asked Questions (FAQs)