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

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.