Gilead Sciences has received US FDA approval for Yeztugo, its bi-annual HIV prevention injection, which has shown 96 per cent effectiveness in trials. Here's how it works, and what it costs.

Approval of first twice-yearly HIV pre-exposure prophylaxis was based on results from the Phase III PURPOSE 1 and PURPOSE 2 trials, which show that ≥99.9% of patients treated with Yeztugo remained HIV-negative.