Bilcke J, et al. - Given the recommendation by WHO in 2017 for the programmatic use of typhoid Vi-conjugate vaccine (TCV) in endemic settings, and Gavi, The Vaccine Alliance, has pledged support for vaccine introduction in these countries, researchers performed country-level health economic evaluations to inform decision-making. Following four strategies were compared in this modeling study: no vaccination, routine immunization at 9 months, and routine immunization at 9 months with catch-up campaigns to either age 5 years or 15 years. Either no vaccination or TCV immunization including a catch-up campaign was identified as the optimal strategy. Considering a willingness-to-pay (WTP) value of at least US$200 per disability-adjusted life-year (DALY) averted, or considering a WTP value of at least 25% of each country's gross domestic product (GDP) per capita per DALY averted, at a vaccine price of $1·50 per dose (but excluding Gavi's contribution according to each country's transition phase), they identified routine vaccination with a catch-up campaign to 15 years of age as optimal in 38 countries. In 48 countries, in addition, this vaccination strategy was assuming a WTP of at least $500 per DALY averted; in 51, it was identified optimal assuming WTP values of at least $1000; it was identified optimal in 47 countries assuming a WTP value of at least 50% of GDP per capita per DALY averted, and in 49 assuming a minimum of 100%. Countries with 300 or more typhoid cases per 100,000 person-years are likely to display cost-efficacy of vaccination. The optimal strategy was most influenced by the uncertainty about the probability of hospital admission (and typhoid incidence and mortality). Based on these findings, they recommend countries to build their own WTP threshold and consider routine TCV introduction, including a catch-up campaign when vaccination is optimal on the basis of this threshold.