Prevalence and genotype distribution of human papillomavirus infection among 4161 women in Shandong Province

Objective To investigate the prevalence and genotype distribution of human papillomavirus (HPV) infection among female outpatients in Shandong Province. Methods Cervical swabs of 4161 females from 171 local community hospitals and health stations from March 2014 to June 2015 were referred to Jinan KingMed Diagnostics and tested by a HPV genotyping chip, which can detect 21 HPV types using flow-through hybridization. The prevalence and genotype distribution in six age groups (101 cases in ≤20 age group, 953 cases in 21-30 age group, 1368 cases in 31-40 age group, 1262 cases in 41-50 age group, 330 cases in 51-60 age group and 56 cases in >61 age group) were documented and analyzed. Results A total of 1325 cases were HPV-positive and the positive rate was 31.8%. The positive rates of high-risk HPV (hrHPV) and low-risk HPV (lrHPV) were 27.3% and 10.4% respectively. Both the prevalence of hrHPV (46.5%) and lrHPV (45.5%) was highest in ≤20-year age group, and gradually declined as age increased. The hrHPV-positive rate slightly increased in 50~60-year age group (26.1%). Similar age-specific prevalence was observed in multiple HPV infection(double or more subtype, the age-specific constituent rates were 63.9%, 44.1%, 32.8%, 32.6%, 27.7% and 26.7%, respectively), pure lrHPV infection(the age-specific constituent rates were 24.2%, 16.9%, 13.0%, 12.2%, 8.5% and 20.0%, respectively), hrHPV and lrHPV mixed infections(the age-specific constituent rates were 50.0%, 25.9%, 14.1%, 11.0%, 12.8% and 6.7%, respectively). In contrast, the percentages of single HPV(the age-specific constituent rates were 37.1%, 55.9%, 67.2%, 67.4%, 72.3% and 73.4%, respectively)and pure hrHPV infections(the age-specific constituent rates were 25.8%, 57.2%, 72.9%, 76.8%, 78.7% and 73.3%, respectively)showed an upward trend as age increased. All 21 HPV genotypes were detected (ranging from 0.1% to 18.3%). HPV16 (13.6%), HPV52 (11.1%), HPV58 (7.7%), HPV53 (6.9%) and HPV51 (4.7%) were the most common hrHPV genotypes. HPV6 (6.8%), HPV11 (5.5%) and HPV81 (5.4%) were the most common lrHPV genotypes. HPV16 was more common in single infection than in multiple infection (18.3% vs 10.7%), while HPV53 and HPV33 showed opposite distributions that they were more common in multiple infection than in single infection (4.9% vs 8.1% and 2.3% vs 4.0% respectively). The proportion of hrHPV and lrHPV mixed infection increased when the number of HPV subtype in the infection increased in these cases. 35.9% hrHPV and lrHPV mixed infections were detected in 287 two subtype infection cases, 61.6% hrHPV and lrHPV mixed infections were detected in 125 three subtype infection cases and 78.7% hrHPV and lrHPV mixed infections were detected in 80 four or more subtype infection cases. Conclusions The prevalence and genotype distribution of HPV infection are influenced by ages, number of HPV subtypes that co-infect the patients and infection modalities in Shandong Province. The characteristics of HPV infection among these female outpatients can serve as valuable reference to guide cervical cancer screening and HPV vaccination programs. Key words: Human papillomavirus; Genotyping; Cervical cancer