Worldwide, cervical cancer affects 500 000 women and causes
275 000 deaths annually. Persistent infection with one of 13
oncogenic types of human papillomavirus (HPV) is now known to
be the cause of both squamous and adenocervical carcinomas
of the cervix. The Pap test involves the examination of exfoliated
cells from the cervix and has been shown to be an effective way of
detecting the precursors of squamous cell carcinoma. In Australia,
commencing in 2007, a free quadrivalent HPV vaccine was offered to
all females aged 12–26 years.
This article looks at why a substantial number of young women who
have been vaccinated with the HPV vaccine will still have Pap test
Prophylactic efficacy of the two HPV vaccines against specific HPV
types is almost 100%. This knowledge has created an expectation
of the demise of both cervical cancer and Pap test abnormalities.
Efficacy of the vaccine is dependent upon the recipient not having
been infected with that HPV type. It is likely that most of the
women aged 18–26 years who have had the HPV vaccine were
already sexually active and therefore exposed to one or more HPV
types. We can still expect to see a substantial number of young
vaccinated women with Pap test abnormalities, due to both HPV
exposure before vaccination and to the many HPV types not covered
by the vaccine. A noticeable reduction in cancers and Pap test
abnormalities will not be seen for some years.
Worldwide, cervical cancer affects 500 000 women and causes 275 000 deaths annually.1 There are two major types of cervical cancer: squamous cell carcinoma (SCC) and adenocarcinoma. Squamous cell carcinoma arises at the transformation zone of the cervix; adenocarcinoma arises higher (and often deeper) in the canal. Persistent infection with one of at least 13 oncogenic HP V types is now known to be the cause of both squamous and adenocervical carcinomas.2
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