A
vaccine effective against four common forms of Human Papilloma
Virus (HPV) has been developed and shows excellent ability (100% effective) to
prevent cervical pre-cancer (CIN2/3) and cancer in situ as well as vaginal and vulvar pre-cancer that are related to these strains of HPV.
The
vaccine known as GARDASIL ™ developed by Merck and Co and CSL is highly
effective against HPV types 6, 11, 16 and 18. Full protection requires a course
of three injections.
In women
who are already infected by one of the above strains, the vaccine is effective
in preventing infection with the remaining strains.
HPV
types 16 and 18 are important co-factors that account for an estimated 70 % of
all cervical cancers as well as some vaginal cancers. HPV types 6 and 11
account for an estimated 90 % of genital warts, so the vaccine will provide
welcome protection against these as well.
Note
that this does not mean that such a high percentage of carriers of the virus
develop cervical cancer. In the vast majority of woman who already one or more of the HPV viruses will not
develop cervical cancer , as the body mounts an immune response against the
virus itself and it may go away on its
own .
.
Between
50 to 80 % of women will have one or other strain of HPV by the time they are
50, but the vast majority will not develop cervical cancer. The mainstay of
preventing cervical cancer has been and remains regular cervical smear tests
which detect the early pre-cancerous changes in the cervix. Many women need
more regular smear tests and /or colposcopy
because of changes brought about by these viruses.
Widespread
uptake of this vaccine is likely to save many women from this sort of more
intensive monitoring as well as actually greatly reducing the final incidence
of cervical cancer and genital warts.
As
cervical cancer is the second most common cause of cancer death in women on a
worldwide basis, this vaccine represents a significant public health advance.
The
vaccine efficacy studies in males are ongoing.
The
optimum age for a good immune response to the vaccine is between 9 and 15 years
old.
The
vaccine is best given before any exposure to HPV but is also effective against
the remaining strains in women who have already been exposed to one or other
HPV strains.
It
obviously makes sense for the population to be protected before they are
sexually active, so that maximum benefit will be obtained from vaccination.
Side
effects included local reactions and fever.
The main
clinical trials of the vaccine are known as The Future 1 and Future 11.The age
of participants in these studies were 16 to 26.
The
Vaccine has recently been approved by the FDA and is available free of charge
on the immunisation schedule for girls aged 11 to 18.