Women who have been vaccinated against the human papillomavirus (HPV) are neglecting their 2-yearly Pap smears at higher rates than unvaccinated women, jeopardizing benefits of the vaccine, according to research published in the Medical Journal of Australia.
Associate Professor Marion Saville, from the Victorian Cytology Service, and her coauthors found that participation in cervical screening during the period 2010-2011 was significantly lower in 25 - 29-year-old vaccinated women compared with their unvaccinated peers (45.2% v 58.7%).
Over the same period, only 37.6% of vaccinated women aged 20 - 24 years were screened compared with 47.7% of unvaccinated women of the same age, the researchers also found.
The three-dose quadrivalent vaccine used in the national HPV vaccination program protects against the two HPV types which cause 70% - 80% of cervical cancer, but it does not provide universal protection, nor does it protect women who acquired HPV before vaccination, making continued screening critical. Despite the fact that most young women know that Pap tests are still needed after vaccination, "our study suggests that this knowledge has not translated into action", A/Prof Saville and her coauthors wrote.
"Whether vaccinated or not, it is important that all Australian women participate in cervical screening, especially once they turn 25", said A/Prof Saville
"In the meantime, efforts to increase participation in screening by vaccinated women are needed." In an editorial in the same issue of the MJA, Dr Annabelle Farnsworth, from Douglass Hanly Moir Pathology, wrote that this trend is concerning given recent evidence from England.
"[In] 2003, the age of commencement of cervical screening in England was raised from 21 years to 25 years", Dr Farnsworth wrote. "This change was based on modelling data and was considered to be safe.
"Subsequently, there has been ... a significant increase in cervical cancer in the 25 - 29-year age group.
"The proposed explanation for the increase in cervical cancer was an increase in HPV infections.
"In April this year, the Medical Services Advisory Committee announced recommendations to significantly alter cervical screening in Australia. The recommendations include: replacing cytological testing for primary screening with HPV testing ... [and] increasing the age of commencement to 25 years ...
"It is hoped that in a vaccinated population, raising the age for commencing cervical screening to 25 years will not have the same consequences as in England", she wrote.