Typhoid Conjugate Vaccine: A Preventable Crisis in India

Recently, Bangladesh became the eighth country globally to introduce the Typhoid Conjugate Vaccine (TCV).
Target Population: Nearly 50 million children aged 9 months to 15 years will receive the vaccine as part of a campaign.
Integration: Post-campaign, TCV will be included in the routine immunisation programme.
Significance for India: India produces this vaccine and carries half the global burden of typhoid, yet it is not yet part of the country’s routine childhood vaccination schedule.

Definition: TCV is a vaccine that provides immunity against typhoid fever, caused by Salmonella Typhi.
Dosage: Administered as a single-dose injection, stimulating antibody production.
Efficacy: Effective in infants and young children, unlike older vaccines with age restrictions.
Regional Status: Nepal, Pakistan, and Bangladesh have already started vaccination programs.
India’s Scenario:
- Typbar TCV by Bharat Biotech (manufactured since 2013) was WHO prequalified in 2017.
- India supplies vaccines regionally but has not introduced it in UIP.

Causative Agent: Salmonella Typhi.
Transmission:
- Human-to-human, via faecal or urinary contamination of food and water.
- Vectors like flies can spread it.
- Survives in milk, ice, and food without taste change.
- Asymptomatic carriers can shed bacteria for months to years.
Symptoms & Effects:
- Fever lasting several weeks
- Severe complications: intestinal perforation, which can be fatal
- Children disproportionately affected, leading to loss of schooling and activity
Global Burden:
- 9–12 million cases annually
- Over 100,000 deaths, concentrated in India, Bangladesh, Pakistan
- Controlled in countries with better sanitation, diagnostics, surveillance, and travel vaccination

Childhood Incidence:
- SEFI study (2017–2020): 10 urban and rural sites
- Incidence: 576–1,173 cases per 100,000 child-years
- Higher in poorer urban areas than rural areas
Migration Risk: Extensive labor migration spreads the pathogen between urban and rural areas.
Mortality:
- Estimated 4.5 million cases annually with 8,930 deaths
- India contributes to half the global burden
Future Projections:
- Without intervention: 46 million cases and 89,300 deaths annually
- Affects all age groups in urban areas and young adults in rural areas

Diagnostic Gaps:
- Symptoms mimic dengue, malaria, COVID-19, scrub typhus
- Blood culture is recommended but limited in availability
- Over-reliance on Widal test, which is unreliable
- Lack of antimicrobial susceptibility testing
Antibiotic Resistance:
- Resistance rising since 1950s
- Current treatment: azithromycin and ceftriaxone
- Resistance emerging to both drugs (2021–2024)
- XDR strains in Pakistan pose imminent threat
- Rising resistance increases treatment cost and limits options
Sub-optimal Sanitation:
- Despite Swachh Bharat Mission and Jal Jeevan Mission, water quality remains poor
- Only 6% of urban households have safe water; rural coverage worse
- Environmental surveillance limited and inadequate

Vaccine Introduction:
- WHO recommended TCV in 2018, especially for children in endemic regions
- Private sector cost: ~₹2,000, limiting access
- Inclusion in UIP is essential for health equity
Complementary Measures:
- Strengthen environmental and disease surveillance
- Improve WASH (Water, Sanitation, Hygiene) measures
- Enhance diagnostics and resistance mapping
- Regulate prescriptions
- Conduct post-vaccination efficacy studies
Vaccine Support:
- Cost-effective: Single dose, protection for 3–10 years
- Safe: Co-administered with routine vaccines from 6 months
- Field Trials: Navi Mumbai (2018): 1 lakh doses, cost USD 1.87 per dose
- Produced by Serum Institute of India and Zydus Lifesciences
Policy & International Support:
- NTAGI repeatedly discussed typhoid vaccination since 2016
- GAVI partnership (2023): $250 million to support TCV in UIP
- Implementation remains delayed

The delay in India is concerning as neighbors like Bangladesh, Nepal, and Pakistan have acted decisively.
Typhoid remains a preventable yet deadly disease, disproportionately affecting children and vulnerable populations.
With proven vaccine technology, cost-effective production, and international backing, India has the tools and opportunity to eliminate typhoid.
Action is overdue: Integrating TCV into the routine immunisation programme can save countless lives and prevent economic and social losses.