Table 2.

Characteristics of included studies.

Study	Country	Sample size	Participants	Intervention	Comparator	Outcomes assessed
Denny 201328	South Africa	120	HIV-positive women aged 18 − 25 years from single center in Khayelitsha, Cape Town	60 vaccinated with bivalent HPV vaccine at 0, 1, and 6 months.	60 vaccinated with placebo at 0, 1, 6 months	Anti-HPV-16 and 18 antibodies were measured by ELISA. Adverse events were graded on a scale of 0 (absent) to 3 (preventing normal activities)
Hidalgo-Tenorio 201731	Spain	129	HIV-positive Men having sex with men (MSM) from Spain	66 vaccinated with quadrivalent HPV vaccine (0.5ml). delivered at day 1, 2 and 6 months	63 vaccinated with placebo (0.5ml). delivered at day 1, 2 and 6 months	Anti-HPV-6, 11, 16, 18 antibodies were measured using ELISA. Adverse events were graded on a scale of 1–4
Levin 201034	USA	126	HIV positive children aged 7–12 years, with a CD4% ≥15	96 vaccinated with quadrivalent HPV vaccine (0.5ml) at 0, 8, 24 weeks.	30 vaccinated with placebo (0.5ml) at 0, 8, and 24 weeks	Anti-HPV 6,11,16,18 antibodies were measured using a competitive Luminex immunoassay. Adverse events were graded (≥1 for injection reactions; ≥2 for all others). That occurred within 14 days of each vaccination were grouped into 5 defined toxicity categories.
Toft 20144	Denmark	92	HIV-positive adults who attended outpatient clinic of Aarhus University Hospital,	46 vaccinated with quadrivalent HPV vaccine at 0, 1.5, and 6 months	46 vaccinated with bivalent HPV vaccine at 0, 1.5, and 6 months	Anti-HPV-16 and 18 antibodies were measured using pseudovirion-based neutralization assay. Adverse events were graded according to the common toxicity criteria version 2.0
Wilkin 201839	USA & Brazil	575	HIV-infected adults aged ≥27 years from 24 sites in the U.S. and Brazil	288 vaccinated with quadrivalent HPV vaccine at 1, 8, and 24 weeks	287 vaccinated with placebo at 1, 8, and 24 weeks.	Anti-HPV-6, 11, 16, and 18 antibodies were measured using competitive Luminex-based immunoassay Adverse events were graded using Division of AIDS Table for Grading the Severity of Adult Adverse Events Version 1.0 Adverse events were solicited during clinical assessments and graded using Division of AIDS Table for Grading the Severity of Adult Adverse Events Version 1.0