IPM Take
Typhoid vaccination is no longer just an infectious-disease intervention. WHO is increasingly treating it as part of the antimicrobial-resistance strategy.
That changes the political calculation. Governments assessing whether they can afford typhoid conjugate vaccine must also account for what happens when resistant Salmonella Typhi infections become harder and more expensive to treat.
Executive Summary
WHO issued a new position paper on typhoid vaccines on 18 August, replacing its 2018 guidance and focusing primarily on typhoid conjugate vaccines.
WHO now recommends TCV for routine immunisation in typhoid-endemic countries and prioritises its use where incidence is high or very high, case-fatality rates are high, or the burden of antimicrobial-resistant S. Typhi is substantial. In very-high-incidence settings, countries should consider a booster at around five years of age for children who received their first dose between nine and 24 months.
Why it matters
- Health ministries: Vaccine decisions should now explicitly include local antimicrobial-resistance patterns, not only case incidence.
- Immunisation programmes: New booster options require countries to think beyond infant schedules and consider schools or community outreach.
- Payers and policymakers: The economic value of vaccination includes prevented disease, prevented antibiotic use and potentially slower emergence of resistance.
Typhoid has long sat awkwardly between two policy worlds. One treats it as a vaccine-preventable infection concentrated in places with poor water and sanitation. The other treats resistant Salmonella Typhi as part of the accelerating global antimicrobial-resistance crisis. WHO’s new vaccine position paper brings those two worlds much closer together.
The updated guidance replaces the 2018 position paper and makes typhoid conjugate vaccines the clear centre of routine prevention policy. WHO recommends TCV use in endemic countries and particularly prioritises introduction where incidence is high, case-fatality is substantial or antimicrobial-resistant typhoid represents a significant burden.
That third criterion matters. Vaccination is increasingly being recognised not simply as protection against infection but as a way to reduce reliance on antibiotics in the first place. Prevent a resistant typhoid infection and a patient avoids needing treatment for that infection. Prevent a febrile illness and there may also be fewer opportunities for unnecessary antibiotic prescribing. At population level, that means vaccination can potentially reduce the selection pressure that helps resistance spread.
The guidance also becomes more nuanced about timing. In high and very-high-incidence settings, WHO recommends first vaccination between nine and 24 months of age. Medium-incidence countries may still introduce TCV, particularly where mortality or antimicrobial resistance is high, but can consider later administration depending on epidemiology and programme feasibility.
Perhaps the most consequential change is the treatment of booster doses. Countries with very high typhoid incidence should consider a booster at around five years for children vaccinated during infancy. High-incidence settings may also consider one where evidence suggests protection is waning. WHO stops short of imposing a universal booster schedule, recognising that the epidemiology and implementation capacity vary significantly between countries.
That flexibility is sensible, but it places greater demands on surveillance. A government cannot tailor vaccination intelligently if it does not know its true typhoid incidence, the age groups most affected, circulating resistance patterns or whether vaccine protection is declining. WHO itself acknowledges that systematic surveillance remains limited in many endemic settings.
The policy therefore creates an important paradox. The countries with the greatest potential benefit from a more sophisticated typhoid strategy are often those with the least complete data needed to design it.
Financing compounds the challenge. WHO’s evidence review found that concerns around affordability, competing immunisation priorities and epidemiological evidence were more influential in national decision-making than cold-chain limitations or public acceptance. In other words, the barrier is increasingly not whether TCV works. It is whether governments can fit another effective intervention into already crowded and underfinanced vaccination programmes.
The new WHO paper provides a stronger technical case for doing so. The remaining question is whether budgets will move as quickly as the evidence.
