HPV Vaccination Programs, Part one: Understanding the Virus

By Ellen Bown, Contributing Author from the UK

Are HPV Vaccines Necessary?

The Human papillomavirus (HPV) was first discovered in the 1950’s however, it wasn’t until the 1970’s that some individual strains were first identified[1]. Today we now recognize there are over a 100 different strains of HPV.  Each type has been given a different number so it can be identified. They can affect the skin and the moist membranes that line parts of the body, including:

          • The lining of the mouth and throat
          • The vulva
          • The cervix
          • The vagina
          • The anus

More than 15 of these strains can increase the risk of developing cervical cancer, in particular types 16, 18, 31, 33 and 45. This said, HPV’s alone are not sufficient for the development of cervical cancer. Other agents such as oral contraception, smoking, drinking, low immunity caused by HIV or Aids and unhealthy lifestyles have to be present for infections to develop into pre-cancerous lesions.[2] Most often HPV is transmitted through sexual contact, but not in all cases. Babies can be born already having been exposed to it in their mother’s wombs or during childbirth[3].

Doctor Heather A. Cubie, a consultant clinical scientist in the Specialist Virology Centre, Royal Infirmary of Edinburgh states in Microbiology Today, that:

“The chance of developing an HPV infection during life has been estimated at 80–85 %, with a large proportion of women having been infected by age 30. However, active HPV16 infection has also been shown in the buccal mucosa of primary school children. Furthermore, in a study we carried out on school girls aged 11–12 in Edinburgh, at least 7% had antibodies to HPV16. Surely such children are not all sexually active!”

She goes on to state that, “There is an urgent need to increase public understanding of the way in which cervical cancer develops and to get rid of the perception that cervical cancer is a sexually transmitted disease.”[4]

Some of the strains are considered to be low risk and can cause genital warts.

In the first year of having an HPV infection your body’s own immune system will have fought off 70% of all infections;  two years later the figure rises to 90%.[5] Of the last 10% only half will develop into cervical cancer.[6] One would have to assume that in an ideal world, if everyone had a healthier lifestyle, the last 5% of these infections would not develop. Strains 16 and 18, coupled with other external factors, cause 70% of cervical cancer. The other strains can cause 30%.

It is important to remember that most women with high risk HPV don’t develop cervical cancer.”[7]

We know from research that other factors affect whether you develop a cancer, (such as how well your immune system is working or whether you smoke.) “Women who smoke and have a high risk type of HPV infection are more likely to go on to get cervical cancer.”[8]

The Cancer Research UK website goes on to say,

“Remember that regular cervical screening will pick up abnormal cervical cells before they become cancerous. So even if you have HPV and smoke, you can prevent cervical cancer if you go for screening when you are invited.”

In fact cervical cancer only accounts for 2% of all female cancers and 7% of cervical cancers were linked to smoking, 1% were linked to occupations, 10% were linked to oral contraception’s[9]. In 2008, 2,938 women were diagnosed with this type of cancer[10]. In the last twenty years cervical cancer has halved due to regular pap screening.

So with all this in mind, why do we need a vaccination program?

References:

  1.  http://discovery.yukozimo.com/who-discovered-hpv/
  2. Harper DM, 20.10.10
  3. http://www.babycenter.com/0_human-papillomavirus-hpv-during-pregnancy_1427380.bc
  4. http://www.sgm.ac.uk/pubs/micro_today/pdf/050303.pdf
  5. Harper DM, 20.10.10
  6. War on you, Dr. Diane Harper, October 28th 2009
  7. http://cancerhelp.cancerresearchuk.org/about-cancer/cancer-questions/what-is-the-hpv-virus
  8. Cancer research UK retrieved 7th March 2012
  9. cancer research UK. Parkin, D.M. Cancers attributable to exposure to hormones in the UK in 2010. Br J Cancer, 6 Dec 2011; 105 (S2):S42-S48; doi: 10.1038/bjc.2011.483
  10. http://info.cancerresearchuk.org/cancerstats/types/cervix/?script=true Cancer research UK, retrieved 7th March 2012.

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