How do vaccines help in preventing typhoid?
Typhoid, a bacterial infection caused by Salmonella typhi, remains a major public health concern in India. Typhoid can lead to a high fever, weakness, and abdominal pain, and in some severe cases, it can even be life-threatening. While antibiotics have been traditionally used to treat the infection, the rise of antimicrobial resistance (AMR) has made treatment more challenging. Improvements in sanitation and hygiene can go a long way as preventive healthcare but vaccination remains the most effective way to protect yourself from the disease.
What are the types of typhoid vaccines available?
In India, two types of typhoid vaccines are available:
- Vi Capsular Polysaccharide (Vi-PS) vaccine
- Typhoid Conjugate Vaccine (TCV)
Vi Capsular Polysaccharide (Vi-PS) Vaccine
The Vi-PS vaccine contains a purified antigenic fraction of S. Typhi’s virulence factor. Administered in a single dose, this vaccine provides around 61% protection in the first year, though efficacy declines over time, requiring re-vaccination every three years. It is recommended for children only over the age of 2 years and cannot be administered to infants since it will not lead to an effective immune response.
Typhoid Conjugate Vaccine (TCV)
To overcome the limitations of the Vi-PS vaccine, Vi-polysaccharide antigens have been conjugated to carrier proteins, enhancing immunogenicity. These typhoid conjugate vaccines (TCVs) can be administered to children as young as six months old and adults up to the age of 65 years and offer longer-lasting immunity.
TCVs are recommended by the WHO for children aged 6 months and 23 months in endemic countries like India. The Indian Academy of Pediatrics recommends routine immunisation schedules from 6 months onwards and coadministration with measles-containing vaccines (like MR or MMR) from 9 months of age. If not given earlier, TCV can be given till the age of 65 years.
Why is vaccination important?
While improved sanitation and hygiene play a role in typhoid prevention, it takes a long time for their implementation. Typhoid fever vaccines are essential due to the associated morbidity and mortality, especially in the current increasing prevalence of antimicrobial resistance.
Antimicrobial resistance (AMR)
Typhoid is becoming increasingly harder to treat because the bacteria are no longer responding to commonly used antibiotics. In recent years, even stronger strains called extensively drug-resistant (XDR) typhoid have emerged, making powerful antibiotics ineffective. This leaves azithromycin as one of the last oral drug treatment options. However, cases of typhoid resistant to azithromycin have already been reported in South Asia, raising fears that typhoid could soon become untreatable without using higher injectable antimicrobials.
Can typhoid vaccines fight antimicrobial resistance?
One of the best ways to tackle antimicrobial resistance is by preventing typhoid in the first place. The WHO recommends typhoid conjugate vaccines (TCVs) as an effective solution to reduce AMR. By reducing the number of typhoid cases, these vaccines help decrease the use of antibiotics, which in turn slows down the development of drug-resistant strains. Widespread vaccination as a public health strategy can also prevent large outbreaks, protect communities, and improve overall public health.
Conclusion
With typhoid still posing a significant health threat in India, preventive measures like vaccination remain one of the most effective ways to curb infection and the spread of antimicrobial resistance. While improvements in sanitation and hygiene are crucial, they may not be enough to fully eliminate the risk. Typhoid conjugate vaccines (TCVs), recommended by both the WHO and the Indian Academy of Pediatrics, offer long-lasting protection and can be administered to infants. By ensuring higher vaccination coverage, we can reduce the burden of typhoid, minimise antibiotic use and help prevent the emergence of drug-resistant strains.
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Disclaimer: A public awareness initiative by Bharat Biotech International Limited. This information is for general awareness only and does not constitute medical advice. The doctors, medical facilities and graphics shown are for illustrative purposes only. For any medical advice or any question or concern you may have regarding your condition, consult your doctor.