Introduction to Typhoid Conjugate Vaccines (TCV)
One of the first Typhoid Conjugate Vaccines prequalified by the WHO in 2017 was Typbar TCV by Bharat Biotech, manufactured since 2013.
Global Adoption and India's Role
- Bangladesh has recently introduced TCV as the eighth country globally, targeting nearly 50 million children aged 9 months to 15 years.
- India is a major vaccine supplier for this initiative but has not included TCV in its routine immunization schedule.
Challenges of Typhoid in Bangladesh
Expert Insights: High burden of typhoid, difficulties in diagnosis, and irrational treatments contribute to drug resistance, according to Zakiur Rahman from Brahmanbaria Medical College.
Transmission and Impact of Typhoid
- Caused by Salmonella typhi, transmitted through contaminated food and water.
- Children are heavily affected, leading to loss of schooling and activity days.
- WHO estimates indicate 9-12 million infections and over 100,000 deaths annually, with India, Bangladesh, and Pakistan as hotspots.
Situation in India
The SEFI study (2017-2020) revealed a high incidence of typhoid in urban areas, with geostatistical modeling estimating 4.5 million cases and 8,930 deaths annually in India.
Complications and Diagnosis
- Typhoid mimics diseases like dengue and malaria, complicating diagnosis.
- Blood culture is the recommended diagnostic test but not widely available.
- WIDAL test is unreliable and misused.
Drug Resistance and Treatment
- Resistance to antibiotics like azithromycin and ceftriaxone is increasing.
- Threat of extensively drug-resistant (XDR) strains from Pakistan affecting India.
Water and Sanitation Issues
Despite initiatives like the Swachh Bharat Mission, safe water supply remains limited, with only 6% of urban households having access to safe water.
Recommendations for Typhoid Vaccine Introduction
- Vaccination should be combined with WASH measures, better diagnostics, and prescription regulation.
- WHO strongly recommends TCV for its effectiveness and cost-efficiency.
Vaccine Development and Trials in India
India hosts TCVs by Bharat Biotech, Serum Institute, and Zydus Lifesciences. Field trials in Navi Mumbai support its efficacy.
Universal Immunisation Programme (UIP) Inclusion
- High private sector cost of TCV necessitates inclusion in UIP for health equity.
- The National Technical Advisory Group on Immunisation (NTAGI) has been considering this since 2016.
- A strategic partnership with GAVI is in place but actions on TCV are pending.
Conclusion
With a high burden of typhoid and available vaccine expertise, India needs to include TCV in its routine immunization program to prevent typhoid effectively.