HPV genotype prevalence in Australian women undergoing routine cervical screening by cytology status prior to implementation of an HPV vaccination program

Abstract

Background: Data on the prevalence of cervical HPV genotypes in Australia by age and by grade of cytological abnormality are sparse.

Objective: Measure prevalence of HPV genotypes among 2620 Australian women by age and cytology status.

Study design: Women presenting for routine Pap smear screening were recruited from diverse regions, including a significant sample of Indigenous women. DNA extracts prepared from Thinprep specimens were HPV genotyped by Roche LINEAR ARRAY HPV.

Results: HPV prevalence and genotype distribution were stratified by age (mean 32.6y) and Pap smear result (cytology normal in 86.7%). Overall HPV prevalence was 38.7% with high-risk HPV prevalence of 26.5%. Prevalence of HPV (66.3% in women<21y to 15.3% in women>40y), multiple HPV infection (45.5% in <21y to 5.8% in >40y) and vaccine-targeted genotypes (HPV 6/11/16/18) (34.1% in <21y to 2.4% in >40y) declined significantly with age. The six most common genotypes were: HPV 16 (8.3%), 51 (5.1%), 53 (4.7%), 62 (4.3%), 89 (3.9%) and 52 (3.8%). HR-HPV prevalence increased from 21.1% in women with normal cytology to 80.9% in those with cytologically predicted high-grade abnormalities (HGAs) (p<0.001). The most common genotypes in women with HGAs were HPV 16 (51.1%), 18 (14.9%), 52 (12.8%), 31 (10.6%), and 33 (10.6%): all HR-types.

Conclusion: Pre-vaccination cross-sectional prevalence of HR-HPV infection was high in this sample of Australian women attending for screening. HPV 16 was the commonest high-risk type detected at all ages and cytological grades.

Keywords: CIN; Cervical Cancer; Cervical cytology; Genotype; Human papillomavirus; Linear array.