Towards quality and order in human papillomavirus research.

The International Human Papillomavirus (HPV) Reference Center supports quality and order in HPV research and diagnostics. Notably, the center assigns HPV type numbers to novel HPV types, maintains a reference clone repository, and issues international proficiency panels for HPV genotyping. The established HPV types, currently up to HPV225, belong to 5 different genera: alpha (65 types), beta (54 types), gamma (98 types), mu (3 types) and nu (1 type). Since 2014, 23 novel types have been established, 82.6% of which belong to the gamma genus. Reference clones have been provided to 44 different research laboratories and the global proficiency program for HPV genotyping has seen an increasing participation (currently 146 laboratories) and complete proficiency has increased over time (from 26% to 59% of datasets). In summary, an increasing complexity of the HPVs requires international efforts to support a recognized quality and order among HPV types.