The Role of Vitamin D in Female Reproductive Tract Immunity

Inclusion Criteria: * Serum 25(OH)D ≤ 25ng/mL (62 nmol/L) * In good health, as evidenced by history and procedures at screening visits without any clinically significant systemic disease. * Not at risk of an STI, meaning: In a monogamous heterosexual or same sex relationship with a partner who is not known to be HIV positive and has no known risks for STIs, or Sexually abstinent * Willing and able to comply with study procedures * 21 to 50 years of age * Not at risk for pregnancy, meaning: Protected from pregnancy due to surgical sterilization of participant and or her sexual partner, Consistent condom use, In a same sex relationship or, Abstinent from sexual activity and planning to remain abstinent for the duration of the study * Regular menstrual cycles (every 21 - 35 days) for the past two cycles, per participant report * Willing to use sunscreen of SPF15 or higher when exposed to the sun for at least 15 minutes, and to avoid use of non-study Vitamin D, calcium, and multivitamin supplementation. Exclusion Criteria: * A clinically significant history of an abnormal Pap test (by written report) in the past year that has not been evaluated and/or treated, if indicated, according to standard guidelines * Surgery or biopsy of the vagina or cervix within 14 days * Current STI or lower genital tract infection including HIV-1, Chlamydia trachomatis (CT), Trichomonas vaginalis (TV), Neisseria Gonorrhoeae (NG), Hepatitis B, yeast vaginitis or bacterial vaginosis (BV) (by Nugent score of 7 - 10); this does not include asymptomatic HSV or human papilloma virus (HPV) * Current presence of vulvar, anal and/or vaginal genital warts * Current tobacco use of any amount * Body Mass Index (BMI) of ≥ 35 kg/m2 * History of sensitivity/allergy to any component of the study product, topical anesthetic, or allergy to silver nitrate and/or Monsel's solution * Known bleeding disorder that could lead to prolonged or continuous bleeding with biopsy, or taking anticoagulant drugs * Grade 2 or higher laboratory abnormality, per the August 2009 update of the DAIDS Table for Grading the Severity of Adverse Events * Systemic use in the last two weeks or anticipated use during the study of any of the following: corticosteroids, non-steroidal anti-inflammatory drugs (NSAIDs), antibiotics, anticoagulants or other drugs known to prolong bleeding and/or clotting, antifungals, antivirals (e.g., acyclovir or valacyclovir) or antiretrovirals (e.g., Viread). Note: Participants should avoid NSAIDS except for treatment of dysmenorrhea during menses. Participants may use acetaminophen on an as-needed but not daily basis during the study. * Known risk factors for hypercalcemia (e.g. malignancy or granulomatous disease) or malabsorption syndromes (e.g. celiac disease, radiation enteritis, active inflammatory bowel disease). * Other conditions that, in the opinion of the investigator, would constitute contraindications to participation in the study or would compromise the ability to comply with study protocols, such as any major chronic illness including but not limited to cancer, serious autoimmune disease, metabolic disorders or a major psychiatric disorder (e.g., schizophrenia) * Current participation in any other drug or device study, or any study which, in the opinion of the investigator, would jeopardize interpretation of results of this study * Use of depot medroxyprogesterone acetate (DMPA) in last six months * Use of any other hormonal contraceptive method (oral, transdermal, transvaginal, implant, or intrauterine device) without 2 subsequent, normal menses since stopping hormonal contraceptives * Current use of copper IUD * Currently pregnant or pregnancy within the past 3 months * Currently breastfeeding or having breastfed an infant in the last two months