Directionality of genital human papillomavirus infection transmission within heterosexual couples: a systematic review and meta-analysis.

BACKGROUND Limited evidence indicates greater female-to-male (F-M) transmission of genital infection with human papillomavirus (HPV) relative to male-to-female (M-F). We verified the hypothesis of a differential transmission rate in couple-based studies by conducting a systematic review and meta-analysis. METHODS We searched MEDLINE, EMBASE, Scopus, and Cochrane Library databases for studies published until December 2019. We calculated pooled estimates of F-M and M-F transmission rates and their rate differences per 100 person-months, with 95% confidence intervals (CI), using a random-effects model. We counted occurrences of directionality preponderance for each HPV type. RESULTS We identified 7 eligible studies published between 2008 and 2019, providing data for 752 couples. Pooled estimates for F-M and M-F transmission rates were 3.01 (CI:1.19-7.64; I2=97%) and 1.60 (CI:0.86-2.98; I2=89%), respectively. The overall rate difference was 0.61 (CI:-0.27-1.49; I2=75%). Three studies provided rates by sex and HPV genotype. Two favored a preponderance of F-M (F-M>M-F for 16 HPV genotypes vs M-F>F-M for 11; F-M>M-F for 29 genotypes vs M-F>F-M for 6), and one favored M-F (F-M>M-F for 6 genotypes vs M-F>F-M for 14) transmission. CONCLUSION There was slight evidence for a differential transmission rate favoring higher F-M than M-F transmission with substantial statistical heterogeneity across studies.