Trials of lenacapavir, a drug developed by Gilead Sciences, show the twice-a-year shot is almost 100% effective at preventing HIV infection.Ihsaan Haffejee / AFP via Getty ImagesGilead's lenacapavir shows near 100% efficacy in preventing HIV with twice-yearly shots, reports The Telegraph.Some Latin American countries face barriers to accessing lenacapavir despite running crucial trials.Beyond price, supply is constrained as Gilead works to scale…