[372] Impact of HPV Vaccination on HPV Genotypes and Follow-Up Biopsy Results of Women >30 with Normal Pap Test Results.

Roberto G Gamez, Arbaz Samad, Linjun Xie, Samy Amirouche, Evin H Gulbahce, Stefan E Pambuccian. University of Minnesota, Minneapolis

Background: Gardasil®, a trivalent HPV vaccine that confers protection against infections with HPV6,11,16 and 18 has been used since its FDA approval in June 2006. Despite the fact that it has been approved for use in females aged 9-26, it has also been sporadically used in women over 27.
Women >30 are frequently cotested with Pap tests (PT) and HPV tests, a strategy that minimizes the likelihood of missing significant cervical squamous precursor lesions (CIN2/3), but results in the detection of very few additional CIN2/3 lesions in women with PT interpreted as normal (NILM) in high-quality cytology laboratories.
The aim of this study was to determine the potential impact of HPV vaccination on the HPV genotypes and follow-up CIN2/3 biopsies of women with normal PT.
Design: All liquid-based (Surepath) PT interpreted as NILM from women >30 that had concomitant HPV genotyping performed from 01/01/2001 to 06/30/2009 were identified. HPV testing was performed by a "home-brew" PCR-based method using MY01/11 primers.The study period was divided into a "pre-vaccine" period (P1)(1/1/01 to 6/30/06) and a "post-vaccine" period (P2)(7/1/06-6/30/09) and differences in the frequency of all HPV types identified, high-risk (hr)-HPV types identified and HPV6, 11, 16 and 18 as well as in the follow-up rate of CIN2/3 detected within 6 months of the PT were determined using χ2.
Results: 9498 women >30 with normal PT results had HPV genotyping performed during the study period, 2312 (mean age of 45.14±11.53) in P1 and 7186 women (mean age 44.9±10.7) in P2.

 Total NumberAny HPV Typehr-HPV TypeHPV6HPV11HPV16HPV18
"Pre-vaccine" period2312163 (7.1%)64 (2.7%)10 (0.4%)2 (0.1%)38 (1.6%)4 (0.2%)
"Post-vaccine" period7186533 (7.4%)138 (1.9%)24 (0.3%)6 (0.1%)64 (0.9%)12 (0.2%)
p value .5.01.5.6.0031


There was a significant decline in all hr-HPV types and in the HPV16 rate and combined rate of all HPV types targeted by the vaccine (6/11/16/18)(P<0.001) in the P2.
275 women were biopsied, of which only 9 received a diagnosis of CIN2/3., 6 (0.26%) in P1 and 3 (0.04%) in P2 (p=0.0087).
Conclusions: We observed a significant decline in the rate of hr-HPV types and HPV16 and the combined rates of HPV6/11/16/18 in women with normal PT results in the post-vaccine period. This was associated with a decline in the already low CIN2/3 rate in these women. Since women >30 are not included in the intended HPV vaccination target population, these declines may represent a "herd effect".
Category: Cytopathology

Tuesday, March 1, 2011 2:00 PM

Platform Session: Section D, Tuesday Afternoon

 

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