Can the HPV vaccine protect those with a weak immune system?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

* INCLUSION CRITERIA: 1. Aged 18 to 70 years. 2. Able to provide informed consent. 3. Female study participants who engage in sexual activities that can result in pregnancy must agree to use one of the contraceptive methods listed below at every potentially reproductive sexual encounter, beginning at the baseline visit and continuing until 3 months after discontinuation of the study agent. Acceptable methods are as follows: * Male or female condom with spermicide. * Hormonal (e.g., consistent use of oral contraceptive pill daily or other hormonal method such as contraceptive implant or injection). Hormonal methods must be started 1 month prior to receiving the first dose of study agent. * Diaphragm or cervical cap. * Intrauterine device (IUD). 4\. Must meet criteria for 1 of the 2 study groups, as follows: * Patients with ICL must have: * documented ICL, defined as CD4 cell count \< 300 cells/microL in at least 2 different measurements 6 weeks apart, at any point in the past; and * CD4 cell count \< 300 cells/microL (within 90 days prior to day 0, outside labs will be accepted). * If patient has documented ICL as defined in i. and is currently enrolled in NIH ICL natural history protocol (EPIC 09-I-0102) a CD4 cell count \< 300 cells/ L (within 18 months of day 0) is sufficient for enrollment. * Healthy volunteers must have: * CD4 cell count of greater than or equal to 450 cells/MicroL (within 90 days prior to day 0, outside labs will be accepted). EXCLUSION CRITERIA: 1. Prior receipt of GARDASIL 9 (Receipt of 2-valent and 4-valent versions of vaccine is not exclusionary). 2. Pregnancy or breastfeeding. 3. History of hypersensitivity, including severe reactions to yeast or other component of the vaccine or to a previous vaccination with another GARDASIL vaccine. 4. HIV infection or any other recognized congenital or acquired immunodeficiency (i.e., SCID IL-2/JAK3/ADA, MAGT1, MHC1 deficiency, DOCK8, etc). 5. Current moderate or severe acute illness (i.e., febrile illness, seizure, myocardial infarction, cerebrovascular accident, pulmonary embolism) that in the opinion of the PI, would make the subject unsuitable for the study. 6. Serum creatinine \> 1.5 times upper limit of normal, platelets \< 100,0000/mm3, hemoglobin \< 9 g/dL, or AST/ALT \> 2 times upper limit of normal, immunoglobulin G level \< 450 mg/liter. 7. Current use of systemic glucocorticosteroids or immunomodulants, other than corticosteroid nasal spray or inhaler and topical steroids, which are not exclusionary. 8. Any cancer diagnosis or autoimmune condition requiring systemic chemotherapy or immunomodulant affecting antibody responses (i.e., rituximab, ibrutinib etc.), intravenous or subcutaneous immunoglobulin supplementation, radiation therapy, or immunomodulatory treatment within the previous 6 months (presence of precancerous lesions is not exclusionary 9. Receipt of an investigational vaccine within 2 weeks of day 0. 10. Receipt of ACIP recommended immunizations within 1 week of day 0. 11. Any condition that, in the opinion of the investigator, contraindicates participation in this study.