Typhoid Vaccine: What is It, Types, When to Be Taken & Side Effects

Introduction

Typhoid fever is a serious (and potentially life-threatening) illness caused by the bacterium Salmonella Typhi that spreads primarily through contaminated food and water. Once inside the body, the bacteria rapidly multiply in the intestinal lymphoid tissue known as Peyer’s patches, and eventually enter the bloodstream, leading to infection (bacteraemia)^1,2.  

With increasing urbanisation, poor sanitation, and the growing threat of antibiotic-resistant strains, the global risk of typhoid is rising, especially in communities lacking clean water and proper hygiene^1,2. 

Given the public health threat posed by typhoid fever, vaccination plays a crucial role in prevention. This article explores the typhoid vaccine, what it is, the types available, when it should be administered, and its possible side effects, helping you make informed decisions about protection against this preventable disease. 

What is the Typhoid Vaccine?

The typhoid vaccine is a preventive vaccine that provides immunity against the Salmonella Typhi bacterium, which is responsible for causing typhoid fever^2,3.  

The vaccine consists of either weakened live bacteria or inactive (killed) bacteria (alone or attached to a carrier protein). When the body is exposed to the bacteria or its antigens, it helps in developing long-lasting protection by stimulating the immune system to recognise and fight the bacteria if exposed in the future. While the vaccine does not treat active infection, it plays a critical role in preventing illness and reducing its spread³. 

It is important to note that while the vaccine lowers the chances of getting sick, it doesn’t fully stop the bacteria from spreading (especially in people who carry it for a long time). So, while it helps reduce transmission, it doesn’t completely prevent it. 

Types of Typhoid Vaccines

There are three main types of typhoid vaccines: 

1. Typhoid Conjugate Vaccines

• Contains a Vi polysaccharide (a component of Salmonella Typhi) linked to a carrier protein (like tetanus toxoid)³. 
• Usually given as a single intramuscular injection⁶. 
• Does not contain live bacteria. 
• Provides stronger and long-lasting immune response 
• Increasingly used in routine immunisation programs in endemic countries. 

2. Injectable Typhoid Vaccine (Inactivated, Vi Polysaccharide Vaccine)

• Contains purified Vi antigen from Salmonella Typhi⁵. 
• Given as a single intramuscular injection with need of subsequent booster doses. 
• Does not contain live bacteria, making it suitable for most individuals, including those with weakened immune systems. 
• While this vaccine is inactivated and safe, it is less immunogenic and does not induce long-term immune memory. 

3. Oral Typhoid Vaccine (Live Attenuated, Ty21a Vaccine)

• Contains a weakened strain of Salmonella Typhi⁵. 
• Taken as capsules by mouth over several days⁵. 
• Not suitable for children <6years, people with compromised immune systems or certain medical conditions⁵. 

Why is the Typhoid Vaccine Important?

As of 2019, an estimated 9 million people contract typhoid each year, and approximately 110,000 die from the infection¹. The disease disproportionately affects low- and middle-income countries, where access to clean water, proper sanitation, and healthcare may be limited². 

Vaccination plays a key role in reducing the risk of infection and preventing its transmission, which is especially crucial in areas with frequent outbreaks, improper sanitation, and rising antibiotic resistance. Moreover, by stimulating the body’s immune system to recognise and fight Salmonella Typhi, the vaccine lowers the chances of severe illness, complications, and death. It also helps protect vulnerable populations, making it an essential tool in the global fight against typhoid fever³. 

Who Should Get the Typhoid Vaccine?

The typhoid fever vaccine is recommended for individuals who are at a higher risk of exposure. These groups include: 

• Travelers to Endemic Areas: People visiting countries where typhoid fever is common (particularly parts of South Asia, Africa, and Latin America) should get vaccinated 1 to 2 weeks before travel².  
• People Handling the Bacteria: Professionals who work in labs and may handle Salmonella Typhi bacteria as part of their research or diagnostic work are advised to receive the vaccine as a safety measure. 
• People Living in or Near Outbreak Zones: Individuals residing in communities where typhoid outbreaks have occurred, or where sanitation and water supply are poor, may also be advised to get vaccinated to help control the spread of the disease^1,3. 

Who Should Not Get the Vaccine?

While the typhoid fever vaccine is generally safe and effective, it may not be suitable for everyone. Individuals who should avoid or delay vaccination include: 

• People with Severe Allergic Reactions: Anyone who has had a severe allergic reaction (anaphylaxis) to a previous typhoid vaccine dose or any of its components should not receive it³. 
• Young Children: Age recommendations in young children may vary depending on the specific vaccine used. The oral typhoid vaccine is typically not recommended for children under 6 years of age, while the injectable vaccine is usually avoided in children under 2 years. The typhoid conjugate vaccine is however safe to be given from 6 months of age and is suitable for routine childhood immunization³. 
• Immunocompromised Individuals: People with weakened immune systems (such as those undergoing chemotherapy or taking immunosuppressive medications) should consult their doctor before taking the live oral vaccine. It is usually not recommended in these cases due to the risk of infection, especially the live oral typhoid vaccine^3,4.  
• People with Certain Medical Conditions: Individuals with acute illness, gastrointestinal issues (for oral vaccine), or fever should postpone vaccination until they recover^3,5. 

How is the Vaccine Given

The administration and preparation for all the typhoid fever vaccine types differ in certain aspects: 

1. Typhoid Conjugate Vaccine

• Method: Given as a single intramuscular injection³. 
• Preparation: No special preparation is needed⁶. 

2. Injectable Typhoid Vaccine

• Method: Given as a single injection in the upper arm (intramuscular)⁵. 
• Preparation: No special preparation is needed⁵. 

3. Oral Typhoid Vaccine

• Method: Taken as four capsules on alternate days (one capsule every other day over a week such as days 1, 3, 5 and 7)⁵. 
• Instructions: 
  • Take on an empty stomach (1 hour before a meal). 
  • Swallow the capsule whole with cold or lukewarm water (not hot). 

When and How Often to Get the Typhoid Shot

The typhoid vaccine schedule and frequency depend on the type of vaccine administered^3,5,6: 

1. Typhoid Conjugate Vaccine

• Age Group: 6 months and older^3,5. 
• Timing: Usually, single typhoid vaccine dose; recommended to be taken at least 2 to 3 weeks before potential exposure (e.g., travel)^5,6. 
• Booster: Currently, no routine booster is recommended, but guidelines may vary by country. However, for some types (like PedaTyph) a booster dose is recommended after 24 to 30 months⁶. 

2. Injectable Typhoid Vaccine

• Age Group: 2 years and older^3,5.
• Timing: At least 2 weeks before potential exposure^3,5. 
• Booster: Recommended every 2 years if continued risk of exposure exists, as it does not induce immune memory^3,5.

3. Oral Typhoid Vaccine

• Age Group: 6 years and older^3,5. 
• Timing: A 4-dose typhoid vaccine schedule, with one capsule taken on days 1, 3, 5, and 7. The last typhoid vaccine dose should be completed at least 1 week before exposure^3,5.  
• Booster: Every 5 years for those at ongoing risk³. 

Effectiveness and Safety of the Typhoid Vaccine

Typhoid vaccines are generally effective and safe in preventing typhoid fever. They offer moderate protection, with an efficacy ranging from 50% to 85%, depending on the type of vaccine used⁷.  

While they are not 100% protective, they significantly reduce the risk of infection, especially when combined with good hygiene and safe food and water practices. 

• Typhoid Conjugate Vaccine: Around 81 to 84% efficacy⁸ 
• Vi Polysaccharide Vaccine: Around 55 to 65% efficacy^9,10 
• Oral Ty21a Vaccine: Around 53 to 67% efficacy^11,12 

Vaccine protection may decline over time, particularly for the Vi polysaccharide and Ty21a vaccines, which may require booster doses for continued protection.  

Possible Side Effects of Typhoid Vaccines

Most side effects of typhoid fever vaccines are mild and temporary. Common side effects include⁵: 

• For injectable vaccines: 
• Pain, redness, or swelling at the injection site 
• Low-grade fever 
• For oral vaccines: 
• Headache or tiredness 
• Diarrhoea 
• Nausea 
• Vomiting 
• Abdominal discomfort 

Note: Allergic reactions like rash, itching, and swelling may rarely occur in all types of vaccines. 

When to See a Doctor

It’s important to seek medical advice at certain points related to typhoid vaccination and potential infection: 

• Before Travel: Consult a doctor at least 3 to 4 weeks (depending on the vaccine type as discussed above) before travelling to regions where typhoid is common⁵. This allows enough time to receive the appropriate vaccine and ensure protection. 
• After Vaccination: While side effects from typhoid vaccines are usually mild, you should see a doctor if you experience⁵: 
  • Severe allergic reaction (difficulty breathing, swelling, rash) 
  • High fever  
  • Persistent gastrointestinal issues (especially after oral vaccine) 
• If Symptoms Appear Despite Vaccination: No vaccine offers 100% protection. If you develop symptoms like prolonged high fever, abdominal pain, fatigue, headache, constipation or diarrhoea, especially after travel to an endemic area, consult a doctor immediately².  

Note: Antibiotic-resistant typhoid is a growing concern, especially in South Asia, so prompt diagnosis and blood culture testing are crucial to ensure the right treatment¹³. 

Conclusion

Typhoid vaccination is a simple yet powerful tool in preventing a potentially serious and life-threatening illness. It offers protection against Salmonella Typhi, the bacterium responsible for typhoid fever, which continues to affect millions of people globally each year. 

Vaccines are especially important for travellers to high-risk regions, individuals living in or near outbreak areas, and those working in environments where exposure is more likely. While no vaccine provides complete immunity, typhoid vaccines significantly reduce the risk of infection and severe complications. 

By getting vaccinated, you not only protect yourself but also help limit the spread of disease within communities, making typhoid prevention a shared responsibility and a vital part of public health. 

Also Read: Home Remedies For Typhoid!

Frequently Asked Questions (FAQs)

References

1. World Health Organization. Typhoid [Internet]. WHO; 2019 [cited 2025 Jun 17]. Available from: https://www.who.int/news-room/fact-sheets/detail/typhoid 
2. Bhandari J, Thada PK, Hashmi MF, et al. Typhoid Fever [Internet]. StatPearls Publishing; 2025 Jan; [updated 2024 Apr 19; cited 2025 Jun 17]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK557513/ 
3. Van Camp RO, Shorman M. Typhoid Vaccine [Internet]. StatPearls Publishing; 2025 Jan; [updated 2024 Jul 1; cited 2025 Jun 17]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK470571/ 
4. Tanrıöver MD, Akar S, Türkçapar N, Karadağ Ö, Ertenli İ, Kiraz S. Vaccination recommendations for adult patients with rheumatic diseases. Eur J Rheumatol. 2016 Mar;3(1):29-35. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC5042271/ 
5. Centers for Disease Control and Prevention. Typhoid Vaccine: What You Need to Know [Internet]. CDC; 2019 Oct 30 [cited 2025 Jun 17]. Available from: https://www.cdc.gov/vaccines/hcp/current-vis/typhoid.html 
6. Gloeck NR, Leong T, Iwu-Jaja CJ, Katoto PDM, Kredo T, Wiysonge CS. Typhoid conjugate vaccines for preventing typhoid fever (enteric fever). Cochrane Database Syst Rev. 2023 Jun 14;2023(6):CD015746. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC10266125/ 
7. Pickering LK, Orenstein WO. Active Immunization. In: Long SS, editor. Principles and Practice of Pediatric Infectious Disease [Internet]. 3rd ed. Philadelphia: W.B. Saunders; 2008. p. 48–71. Available from: https://www.sciencedirect.com/science/article/pii/B9780702034688500134 
8. Patel PD, Patel P, Liang Y, Meiring JE, Misiri T, Mwakiseghile F, Tracy JK, Masesa C, Msuku H, Banda D, Mbewe M, Henrion M, Adetunji F, Simiyu K, Rotrosen E, Birkhold M, Nampota N, Nyirenda OM, Kotloff K, Gmeiner M, Dube Q, Kawalazira G, Laurens MB, Heyderman RS, Gordon MA, Neuzil KM; TyVAC Malawi Team. Safety and Efficacy of a Typhoid Conjugate Vaccine in Malawian Children. N Engl J Med. 2021 Sep 16;385(12):1104-1115. Available from: https://pubmed.ncbi.nlm.nih.gov/34525285/ 
9. Klugman KP, Koornhof HJ, Robbins JB, Le Cam NN. Immunogenicity, efficacy and serological correlate of protection of Salmonella typhi Vi capsular polysaccharide vaccine three years after immunization. Vaccine. 1996 Apr;14(5):435-8. Available from: https://pubmed.ncbi.nlm.nih.gov/8735556/ 
10. Klugman KP, Gilbertson IT, Koornhof HJ, Robbins JB, Schneerson R, Schulz D, Cadoz M, Armand J. Protective activity of Vi capsular polysaccharide vaccine against typhoid fever. Lancet. 1987 Nov 21;2(8569):1165-9. Available from: https://pubmed.ncbi.nlm.nih.gov/2890805/ 
11. Simanjuntak CH, Paleologo FP, Punjabi NH, Darmowigoto R, Soeprawoto, Totosudirjo H, Haryanto P, Suprijanto E, Witham ND, Hoffman SL. Oral immunisation against typhoid fever in Indonesia with Ty21a vaccine. Lancet. 1991 Oct 26;338(8774):1055-9. Available from: https://pubmed.ncbi.nlm.nih.gov/1681365/ 
12. Levine MM, Ferreccio C, Black RE, Germanier R. Large-scale field trial of Ty21a live oral typhoid vaccine in enteric-coated capsule formulation. Lancet. 1987 May 9;1(8541):1049-52. Available from: https://pubmed.ncbi.nlm.nih.gov/2883393/ 
13. Parry CM, Ribeiro I, Walia K, Rupali P, Baker S, Basnyat B. Multidrug resistant enteric fever in South Asia: unmet medical needs and opportunities. BMJ. 2019 Jan 22;364:k5322. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC6340381/ 

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