Safety and Acceptability of Tenofovir 1% Gel in Adolescent Females

Inclusion Criteria: * Age 15 through 17 years, inclusive, as per site policy * General good health (by volunteer history and per investigator discretion) without any clinically significant systemic disease (including, but not limited to significant liver disease/hepatitis, gastrointestinal disease, kidney disease, thyroid disease, osteoporosis or bone disease, and diabetes) * Able to communicate in spoken and written English * Willing to following instructions regarding vaginal activity and vaginal products as follows: 1. Willing to abstain from all vaginal activity, including intercourse, for 48 hours prior to Visit 2 and 48 hours prior to Visit 7 2. Willing to abstain from the use of vaginal products other than the study product including spermicides, lubricants, and douches for the duration of study participation. Note: Tampons may be used for menses, but pads should be used for any other intermenstrual spotting or bleeding. * Assessment of onset and progression of puberty as measured by Tanner Stage 4 or 5 * History of consensual penile-vaginal intercourse (at least one episode in participant's lifetime) * Negative urine pregnancy test * Use of an effective method of contraception for at least the past 30 days (per participant report) and intended use for the duration of study participation. Effective methods include: 1. Hormonal methods (excluding contraceptive ring) 2. Intrauterine contraception (IUC) Note: An IUC must be in place for at least 15 days prior to enrollment * Willing to give voluntary assent, and comply with study procedures as required by the protocol assent and willing for parent/guardian to provide written informed consent for participation as per Institutional Review Board (IRB) requirements. Emancipated minors may give their own informed consent. Exclusion Criteria: * Known adverse reaction to study products (ever) or latex, per participant report * Non-therapeutic injection drug use in the last 12 calendar months * Post-exposure prophylaxis (PEP) for HIV-1 exposure within the last 6 calendar months * Currently pregnant or within 30 days from the last pregnancy outcome. Note: If recently pregnant must have had at least two spontaneous menses since pregnancy outcome. * History of gynecological procedures (including genital piercing) on the external genitalia, vagina or cervix within the last 14 days * Intention to become pregnant in the next 6 months * Currently breastfeeding or having breastfed an infant in the last two months, or planning to breastfeed during the course of the study * Positive for HIV * Grade 2 or higher as per the Division of AIDS (DAIDS) Table for Grading Adult and Pediatric Adverse Events, Version 1.0, December 2004 (Clarification dated August 2009) of the following: 1. Alanine transaminase (ALT), aspartate aminotransferase (AST) 2. Creatinine 3. Hemoglobin 4. Platelet count 5. Hepatitis B surface antigen (HBsAg) Note: Otherwise eligible participants with an exclusionary test result(s) listed above may be re-tested a maximum of one time and if a non-exclusionary result is documented within the 30 days of providing informed consent, they may be enrolled. * Clinically apparent Grade 2 or higher pelvic examination finding (observed by study staff) per the Female Genital Grading Table for Use in Microbicide Studies (Addendum 1 to the DAIDS Table for Grading Adult and Pediatric Adverse Events, Version 1.0, December 2004 (Clarification dated August 2009) Note: 1) Cervical bleeding associated with speculum insertion and/or specimen collection judged to be within the range of normal according to the clinical judgment of the Principal Investigator/designee is considered expected non-menstrual bleeding and is not exclusionary. 2) Otherwise eligible participants with exclusionary pelvic examination findings may be enrolled /randomized if improvement of findings to a non-exclusionary grade or to resolution can be documented within 30 days of providing informed consent for Screening. * Current pelvic inflammatory disease (PID) or sexually transmitted infection requiring treatment per current Centers for Disease Control and Prevention (CDC) guidelines (e.g., Trichomonas vaginalis, Neisseria gonorrhea (GC), Chlamydia trachomatis (CT), or active herpes outbreak) * Symptomatic vulvovaginal candidiasis, symptomatic bacterial vaginosis (BV) or urinary tract infection (UTI) Note: Otherwise eligible participants with symptomatic vulvovaginal candidiasis, BV or UTI prior to genital sampling at Visit 2 will be offered treatment and may be continue in the study after completing treatment and all symptoms and findings have resolved. * Systemic use in the last two weeks or anticipated use during the study of any of the following: corticosteroids, antibiotics, antifungals, antivirals (e.g., acyclovir or valacyclovir) or antiretrovirals (e.g., Viread®, Atripla®, Emtriva®, Complera®, Stribild®). Note: Participants should avoid non-steroidal anti-inflammatory drugs (NSAIDs) except for treatment of dysmenorrhea during menses. Participants may use Tylenol® on an as-needed but not daily basis during the study. * Participation in any other investigational trial (device, drug, or vaginal trial) within the last 30 days or planned participation in any other investigational trial during the study * Any other condition that, in the opinion of the Principal Investigator (PI) or designee, would preclude informed consent, make study participation unsafe, complicate interpretation of study outcome data, or otherwise interfere with achieving the study objectives