|LETTER TO EDITOR - TIMARU HERALD - HPV VACCINE 2008-07-16|
Being a mum and having a ten year old daughter I am interested in anything that will be of benefit to her now and in the future, so naturally I was curious about this HPV vaccine programme and the possible benefits for her.
2008- 07- 24 Cancer Vaccine (Replies)
There were a number of factual errors in J Smith's letter (July 15) about the human papillomavirus (HPV) vaccine and immunisation programme. First more than 99 per cent of cervical cancer is caused by HPV infection. (For more information go to www.cdc.gov/mmwr/preview/mmwrhtml/rr5602a1.htm) Gardasil, the vaccine being used for the HPV immunisation programme, protects against the two types of HPV that cause seven out of 10 cases of cervical cancer and the two HPV types that cause 9 out of 10 genital warts.
HPV infection happens in the first years of being sexually active and it takes many years before it progresses to cervical cancer. Protection against the HPV infection therefore needs to be before a young woman becomes sexually active. This immunisation programme will protect women from cervical cancer. It is estimated that in the long term it will save 30 lives a year and reduce the number of women requiring further testing for abnormal smear results. Young women who are vaccinated will still need to have cervical smear tests when they are older as Gardasil does not protect against about 30 per cent of cevical cancers.
Ongoing studies show the vaccine protects against HPV infection for five years after immunisation and suggest protection will last much longer. International experts do not expect booster doses will be needed. Research is continuing to monitor the immune response. Every year in New Zealand 160 women are diagnosed with cervical cancer and 60 die from it. Gardasil has been proven to protect against infection with HPV types 16 and 18, and the changes in cervical cells that may progress to cervical cancer 10-20 years later. Follow up studies will measure the reduction in rates of cervical cancer through cancer registries. I would encourage readers to go to the Ministry of Health's websit for more information about HPV and the immunisation programme, www.moh.govt.nz/immunisation. Resources for primary care, parents, young women and schools are being developed to ensure people have access to credible and reliable information about HPV and the immunisation programme.
Dr Alison Roberts
Senior Adviser Public Health Medicine MINISTRY OF HEALTH
J Smith claims (July 16) that she could not find evidence supporting the Human Papilloma Virus (HPV) as a cause of cervical cancer, suggests that there are no viral genes present in human cervical cancers and that HPV does not replicate in cancer cells. She also says that HPV is not more common in women with cancer than without it and that the new vaccine only provides five years' immunity.
These claims are rather extraordinary as the evidence for the role of HPV in cervical cancer is very well established. This virus is a prerequisite for initiating the steps required for cervical cancer development. The viral genes involved are called E6 and E7 and these genes interfere with host tumor suppressor genes. These viral genes can aso integrate themselves into the host genome, further disrupting cell behaviour. There are two types of HPV (type 16 and 18) that are particularly effective at causing this disruption and the new vaccine targets these types, which are responsible for approximately 70 percent of cervical cancer.
Recipients of the new vaccine have maintained high levels of anitibody against the vaccine viral types for the six years since receiving the vaccine. When some of these recipients received another dose of vaccine at five years the response indicated they had a strong memory for the vaccine. This bodes very well for long-lived immunity. If it were found that vaccine immunity waned over time, I am sure booster doses would be offered in the future. It is important to keep in mind that the objective is to prevent young women developing a persisting HPV infection, therefore reducing their risk of developing cancer. So far the vaccine has proved extremely efficient at this. In clinical trial, of the participants who received all doses of the vaccine and were not already infected with the virus, none developed CIN 2, 3 or cancer, whereas 53 in the placebo group did.
No is suggesting women stop having regular smear tests as this vaccine has the potenetial to prevent most obnormal smears, not all of them. Regular smear testing continues to be recommended to detect abnormalities cased by other HPV types not included in the vaccine.
Immunisation Advisory Centre University of Auckland
Professor Diane Harper, who designed and conducted the clinical trials for the HPV "Gardasil" vaccine conveyed concerns with regard to immunity, in her interview on National Radio (August 01 2008). (www.radio.nz.co.nz - Audio Search - Gardasil) Professor Harper said trials indicated that five years immunity was all that could be confirmed as immunity had been shown waning and it was highly likely that recipients would require booster shots in the future. She also stated that mothers and daughters are being told that by having this vaccine they are one less who will get cervical cancer and that this is simply not true. That this vaccine has never been proven, at this stage, to prevent cervical cancer. It has only been proven to protect women against two types of HPV virus with links to cervical cancer.
Other concerns she raised were that Merck had embarked on a very aggressive marketing campaign with "Gardasil" and that too many girls were being vaccinated too quickly, without waiting to see what long-term results and risks were present in the general population. Many adverse reactions have occurred from this vaccine due to the millions of doses being rolled out and she said this is something parents should be aware of.
Her advice was if your daughter is in the 12-14 year bracket, it could be wise to wait four years until more data was gained on the effects of this vaccine. There is no advantage, in her view, to getting vaccinated at this young age versus 18 years. Prof. Harper has publicly stated that this vaccine is a great big public health experiment.
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