Mike Taylor: Preventing deaths is a clear measure of a vaccine's success

Photo / Wanganui Chronicle

I am writing in response to the column by Tapu Misa (Herald, March 2). In it she raised a number of questions regarding HPV vaccination (Gardasil) that have been discussed for many years and were well considered in the registration and reimbursement of Gardasil here in New Zealand.

>>Tapu Misa: When a shot in the arm's no silver bullet

Gardasil works by helping the body develop protection against the human papillomavirus (HPV) types 6, 11, 16 and 18. These four HPV types account for the majority of cervical cancer cases and a large number of cervical abnormalities.

An in-depth health economic evaluation has been completed on Gardasil here in New Zealand and overseas. Gardasil has been shown to be extremely cost-effective due to the large reduction in HPV-related cervical abnormalities that no longer require extensive follow-up and treatment as well as deaths that are prevented.

It is well understood that Gardasil does not protect against every type of HPV and that regular cervical smears will still be required.

Gardasil has undergone extensive clinical trials including appropriate evaluation in girls aged 9-15 years. More than five years of follow-up data has now been gathered from over 20,000 women in 33 countries including New Zealand.

Ongoing follow-up of 5400 of these women will continue for at least a further 10 years.

Clinical data shows the vaccine remains 100 per cent effective against preventing pre-cancerous lesions from all four HPV types in the vaccine with no evidence of breakthrough of disease. In addition Gardasil has demonstrated immune memory which is a true hallmark of long-term protection.

This means that the body has stored the memory of the vaccine's HPV types so if a woman is exposed to infection the body will automatically produce antibodies to prevent it.

It is not ethical to use cancer as a clinical trial endpoint and it is well recognised that pre-cancers are exactly that, pre-cancers that lead to cancer. By reducing pre-cancers you reduce cancer.

Independent scientists and international medicines safety authorities in over 100 countries have shown that Gardasil is safe and effective.

The most common reactions to Gardasil, as with all vaccines, include soreness, redness and swelling at the injection site, (approximately 90 per cent of all adverse events). Nausea, light-headedness and slightly raised temperature are also relatively common. Any adverse events are followed up in accordance with regulatory guidelines and carefully evaluated, which is the case with all of our medicines and vaccines.

Gardasil is considered a breakthrough in the prevention of cervical cancer and as a result has recently been awarded the 2008 International Galien Prize (pharmaceutical equivalent of a Nobel Prize) by an independent jury of clinicians, toxicologists and pharmacologists.

* Mike Taylor is country manager of CSL Biotherapies NZ, which supplies the vaccine to New Zealand health authorities.