Letter: the word on HPV

By James Mansi, Ph.D.

Editor, the Gauntlet,

The Oct. 2 article by Gina Freeman about the HPV vaccine [“HPV Freakout,” Oct.2, Gina Freeman, Gauntlet] contains critical errors and wants to raise doubts about the safety and efficacy of Gardasil.

HPV is not just “linked” to cervical cancer. HPV causes cervical cancer– without this viral infection, cervical cancer cannot develop.

And while it is true that there are many types of HPV, Gardasil is 96 to 100 per cent effective at preventing infections from the four types (HPV six, 11, 16 and 18) that cause the most clinical disease, including 90 per cent of all cases of genital warts, 70 per cent of all cervical cancers and 55-72 per cent of vulvar and vaginal cancers.

Ms. Freeman’s article also gives the impression that Gardasil has not been thoroughly tested. Gardasil has in fact benefited from 10 years of research and development including over five years in clinical trials involving close to 25,000 people in 33 countries. This is one of the most extensive research programs in terms of subjects studied and length of evaluation supporting the approval of a vaccine.

As for its safety, and according to the Public Health Agency of Canada, the reporting rate for adverse events for Gardasil in Canada is roughly 33 per 100,000 doses distributed. Reports are mostly of minor adverse events. This is comparable to the rate of reported adverse events for all vaccines in Canada, which has varied from 16 to 40 per 100,000 doses over the period 1992-2004. In the clinical trials, the number of serious adverse events in girls/women who received the vaccine were rare and in general were similar to those who received the placebo.

HPV infections in Canada annually lead to approximately 400,000 abnormal Pap smear results, 85,000 consultations due to genital warts and 36,000 new cases of genital warts, as well as 1,400 cervical cancer diagnoses and 400 cervical cancer deaths. HPV is also linked to cancers of the vagina and vulva.

It is precisely this combination of safety profile, efficacy and burden of disease that led to the Health Canada approval of Gardasil in 2006 followed by the numerous endorsements from major medical organizations, representing thousands of health-care professionals across Canada, including the National Advisory Committee on Immunization, the Regroupement des gynecologues oncologues du Quebec, the Society of Obstetricians and Gynaecologists of Canada, the Society of Gynecologic Oncologists of Canada, the Society of Canadian Colposcopists and the Canadian Paediatric Society.

We encourage readers to consult their physicians to obtain accurate information about the safety and efficacy of Gardasil.

[There were no errors in the piece. There are many different statistics to do with the relation between HPV and cervical cancer. Depending upon which you look at, it may lead to different conclusions. It is interesting to note that there is a contradiction in this letter: in the second paragraph it is stated that cervical cancer cannot develop without HPV infection, but in the following paragraph it is recorded that 70 per cent of cervical cancer cases are caused by HPV infections.

Further, not all medical bodies agree on the exact cause of cervical cancer.- Ed.]




Correction: The Ed note attached to this letter incorrectly states that there is a contradiction between paragraphs 2 and 3, which is not the case. The Gauntlet regrets this error.