Prevalence and distribution of high-risk human papillomavirus in Greece

As knowledge of regional human papillomavirus (HPV) type distribution is essential for the optimization of prevention strategies, this study was carried out to explore the prevalence and type distribution of high-risk HPV in a screening population across Greece. Cervical samples were collected by local physicians and nurses in hospitals and health centers across the country from 4139 women attending for cervical cancer screening. High-risk HPV-DNA was detected by using Hybrid Capture-2 (HC2) and positive samples with adequate cellular content were further typed by restriction fragment length polymorphism-polymerase chain reaction. Almost six percent (5.9%) of women tested positive in HC2. The most common type was HPV16 (1.4% in the whole sample and 32.4% of the typed samples), followed by HPV53 (0.6 and 14.0%, respectively), HPV31 (0.6 and 12.9%, respectively), HPV35 (0.5 and 12.3%, respectively), HPV51 (0.4 and 7.8%, respectively), HPV18 (0.3 and 7.3%, respectively) and 22 more types. Almost 15% of the typed samples showed a coinfection with two HPV types and 2.1% with three types. There was a bimodal distribution by age, with the highest peak in women 20-29 years old and a lower peak in women 50-59 years old. Apart from the types originally included in HC2 cocktail, PCR analysis identified 15 more types (HPV6, HPV11, HPV34, HPV37, HPV38, HPV42, HPV53, HPV54, HPV55, HPV61, HPV62, HPV66, HPV73, HPV82, HPV83). Eleven percent of HC2-positive results arose from single-type infections with HPV53 (10%) and HPV66 (1%), which are potentially high-risk types. In conclusion, HPV16 is the most common type in the largest Greek screening sample used to date and, together with its related types, accounts for more than half of high-risk HPV infections. Approximately 10% of positive HC2 results arise from HPV53, which is not normally detected by the test, but may be clinically significant.