Despite the recent controversy surrounding Merck's HPV vaccine, Gardasil, the FDA just approved two new cancer indications and updated the safety information relating to deaths and illnesses. Conservative public interest groups have long been advocating that the vaccinations should not be mandatory in the under 18's, advocating abstinence as a more effective treatment.
The FDA newswire announced that it had approved Gardasil for the prevention of vaginal and vulvar cancer caused by
Human Papillomavirus (HPV) types 16 and 18 in girls and women ages 9 to 26.
These two HPV types cause 70 percent of cervical cancers, and are known to
also cause some vulvar and vaginal cancers, but the percentages are not well
In the new indications for the prevention of vulvar and vaginal cancer, more than 15,000 participants from the original
studies for about two additional years were followed. Approximately half had received Gardasil
as part of the original study, the other half did not receive Gardasil
and served as a control group.
Among females who tested negative for HPV types 16 or 18 at the start of the
study, Gardasil was highly effective in preventing these types of HPV-related
precancerous vulvar and vaginal lesions, which are considered to be the precursors
In the control group that did not receive the vaccine, 10 individuals
developed precancerous vulvar lesions and nine developed precancerous vaginal
lesions, all related to HPV types 16 or 18. No one in the Gardasil group developed
either kind of precancerous lesion due to HPV types 16 or 18.
There was no evidence for benefit among women found to have been previously
infected, prior to immunisation, with the HPV types included in the vaccine. To receive Gardasil’s full potential for benefit, it is therefore important
to be vaccinated prior to becoming infected with the HPV strains contained
in the vaccine.
Gardasil was originally in 2006 for girls and women ages 9 to
26 for the prevention of cervical cancer caused by HPV types 16 and 18, precancerous
genital lesions caused by HPV types 6, 11, 16, and 18 and genital warts caused
by HPV types 6 and 11. A recent study, published in the prestigious New England Journal of Medicine, suggested that Gardasil isn't economically viable for women over 18, but Merck argues that the vaccine is cost effective in women up to 24 years old.
The FDA revised Gardasil’s label to include information that presently available data
is insufficient to support use beyond age 26, the current FDA-approved age.
Additional information has also been added showing that Gardasil does not protect
against diseases caused by HPV types not contained in the vaccine.
No vaccine is 100 percent effective, and Gardasil does not protect against
HPV infections that a woman may already have at the time of vaccination. It is important that all women should get regular Pap tests, even after they have been vaccinated.
Routine Pap screening still remains critically important to detect precancerous changes,
which would allow treatment before cancer develops.
The prescribing information includes reports of deaths, seizures, autoimmune
disorders and paralysis in patients given the vaccine (Guillain Barre Syndrome), without
indicating any link to the vaccine. In July, the Centers for Disease
Control and Prevention indicated Gardasil was safe after reporting that
20 people died following the injection, but the deaths could be
unrelated and no additional precautions were needed.
As part of the original approval, Merck committed to a large safety surveillance
study of 44,000 individuals in a managed care organization. The study is assessing
short- and long-term safety for all of Gardasil’s approved uses. It will be interesting to see what the long term effects of the vaccine are over a 10 year period, but that data will not be available for quite a while yet.