 This study will last 24 weeks, with an additional 10 weeks of follow-up for participants with chronic hepatitis B virus HBV infection. Participants will be randomly assigned to one of four arms. Arm A participants will insert a vaginal tenofovir 1 gel two hours prior to vaginal intercourse for a maximum of two daily applications. Arm B participants will insert a vaginal placebo gel two hours prior to vaginal intercourse for a maximum of two daily applications. Arm C participants will insert a vaginal tenofovir 1 gel once daily at bedtime or during the longest period of daily rest. Arm D participants will insert a vaginal placebo gel once daily at bedtime or during the longest period of daily rest. 