On Mar. 28, 2007, the FDA announced that GlaxoSmithKline (King of Prussia, Pennsylvania) received approval for an alternate schedule for Twinrixﾮ, a combined hepatitis A and hepatitis B vaccine. Twinrix was first licensed by FDA in 2001 on a 3-dose schedule (0, 1, and 6 months) for vaccination of persons aged >18 years. Using the newly licensed, alternate 4-dose schedule, Twinrix doses can be administered at 0, 7, and 21–30 days, followed by a dose at 12 months.