Abraham S, Juel HB, Bang P, et al. - Researchers conducted phase 1, first-in-human, double-blind, parallel, randomized, placebo-controlled trial investigating the safety and immunogenicity of a novel chlamydia vaccine in humans in a prime-boost immunization schedule; the vaccine is based on a recombinant protein subunit (CTH522). At Hammersmith Hospital in London, UK, randomization of 35 healthy women aged 19–45 years (3:3:1) to three groups was done: CTH522 adjuvanted with CAF01 liposomes (CTH522:CAF01), CTH522 adjuvanted with aluminium hydroxide (CTH522:AH), or placebo (saline). Outcomes suggest safety with well-tolerability of CTH522 adjuvanted with either CAF01 or aluminium hydroxide. Although both vaccines were identified as immunogenic, further clinical development is recommended for CTH522:CAF01 in view of its better immunogenicity profile.