Update on CVD 103-HgR single-dose, live oral cholera vaccine.

INTRODUCTION Cholera remains endemic in >50 countries, putting millions at risk, especially young children for whom killed vaccines offer limited protection. An oral, live attenuated vaccine - CVD 103-HgR (Vaxchora vaccine) - was licensed by the US FDA in 2016 for adults aged 18-64 years traveling to endemic regions, based on clinical trials in human volunteers showing the vaccine was well-tolerated and conferred 90% efficacy within 10 days. AREAS COVERED The evidence base for Vaxchora vaccine has expanded with additional clinical trial data, in older adults (aged 46-64 years) and children (aged 2-17 years), demonstrating that the vaccine is well-tolerated and produces a cross-strain vibriocidal antibody response and seroconversion rates associated with protection from cholera diarrhea. Over 68,000 doses have been administered in the USA, with no new safety signals. The dose volume has been reduced in children to improve acceptability, and cold chain requirements are less stringent, at +2°C─+8°C. The vaccine has recently been licensed in the USA for children aged 2-17 years, in Europe for individuals aged ≥2 years, and for home administration in Europe. EXPERT OPINION Next steps include a Phase 4 study in infants (6-23 months). Additional information is needed regarding duration of immunity, the need for and timing of revaccination, and efficacy data from lower-middle-income countries.