Epidemiological evaluation of human papillomavirus genotypes and their associations in multiple infections.

The aim of this study was to determine the frequency of multiple type human papillomavirus (HPV) infections, and whether any types are involved in multiple HPV-type infections (mHPV) more or less frequently than expected. From January 2012 to February 2018, 2848 cervico-vaginal swabs were analysed in the UOC Microbiology and Virology of Policlinico of Bari, Italy. HPV DNA detection was performed using initially nested-polymerase chain reaction (PCR) and subsequently multiplex real-time PCR assay. 1357/2848 samples (47.65%) were HPV DNA positive and 694/1357 (51.14%) showed mHPVs. The median number of mHPVs was 2 (interquartile range: 2-3). HPV-types more frequently detected were 42 (9.97%), 16 (8.92%), 53 (7.23%) and 31 (7.16%). Each detected HPV-type was involved in mHPVs in more than 50% of cases. Statistical analysis showed significant associations for all HPV-types except for 33, 43, 51, 58 and 82 HPV-types. The major number of significant pairwise associations were detected for the types 42 and 70. Only positive associations were detected. Further data are necessary to evaluate the clinical impact of the single combinations.