HPV Vaccination - Facts, Side Effects and Risks
HPV or Human Papillomavirus is the most common STD
(sexually transmitted disease) in the United States,
so much so that around 75% of men and women will be
infected with the virus at some time in their lives.
HPV is contagious, with the strains that cause genital
warts and cancer being very contagious. HPV is easily
transmitted during sexual activity and infected people
may not even be aware that they have the virus. This
is because some strains produce no symptoms and not
everyone exposed to other strains will have any symptoms.
The strains that lead to cervical cancer in women and
genital warts are in the high-risk category.
In an attempt to prevent the incidence of cervical
cancer, research was started in the 1980s to find a
suitable HPV vaccine for the strains of the virus that
are precursors to cancer. This work was being carried
out by 4 different research teams simultaneously –
at the University of Queensland in Australia, the University
of Rochester, Georgetown University and the US National
Cancer Institute. The first HPV vaccine was produced
by Merck and Company, under the brand name Gardasil.
By mid 2007, Gardasil had been approved for use in 60
countries, while a second HPV vaccine by GlaxoSmithKline
had been approved, called Cervarix, though it wasn't
approved for U.S. use until 2009.
Both brands of HPV vaccination protect women against
HPV-16 and -18 which are the strains that cause about
70% of cervical cancers and are implicated in other
types of genital cancers as well. Gardasil also offers
protection against HPV-6 and-11 which are responsible
for genital warts, as well as the several strains that
appear to be precursors for anal, penile, vaginal, vulvar
and oral cancer caused by HPV.
Western countries, including Australia, Europe, Canada
and the United States recommend HPV vaccination for
girls and young women in an effort to prevent cervical
cancer. Some of these countries have made the vaccine
available at no charge to girls in the optimum age group,
with Australia having a school-based immunization program
for girls in their first year of high school (about
12 years of age). The US has approved the use of Gardasil
for young men and boys because it has been shown to
be effective in preventing genital warts.
HPV vaccination requires three injections, two months
apart, over a six month period. Gardasil has been approved
for girls and women aged from 9 to 45 years and for
boys from 9 to 15 years. Cervarix has been approved
for women and girls aged between 10 and 45 years. Both
vaccines have the best chance of successfully preventing
cancer if they are given before any exposure to HPV,
which means before sexual activity begins. The recommended
age for girls to receive the vaccine is between 9 and
12. Women who have already been sexually active could
still benefit from HPV vaccination provided they have
not already been infected with the HPV strains that
the vaccines cover.
Possible side effects of the HPV vaccine
The HPV vaccine doesn't contain any live virus and
so it isn't able to give you HPV.
Most vaccines have some side effects in some people;
however, the diseases they aim to prevent are way more
dangerous than these possible vaccination side effects.
Most side effects of the HPV vaccine are a reaction
at the site of the injection and include redness, soreness
or swelling, although some cases of headache or nausea
have been reported. These side effects usually disappear
in a few days or less and only affect a small percentage
of those receiving the vaccine. Worldwide, the reported
number of cases of side effects is quite low compared
to the number of vaccine doses that have been distributed.
In September 2009, in the U.S. alone, this number is
more than 26 million doses; there have been 15,000 VAERS
(Vaccine Adverse Event Reporting System) reports that
have followed vaccination. 93% of these reports involved
the non-serious side effect listed above, while the
remaining 7% fell into the serious category, involving
life-threatening, hospitalization or death though none
of these were proven to be linked to the HPV vaccine.
As new clinical evidence is accumulated, product information
on the HPV vaccine is updated but to date, there have
been no regulatory agencies that have needed to take
any corrective action.
The main risk of the HPV vaccine is that women will
become complacent because they believe they are immune
to all strains of HPV. There are well over 100 HPV strains
and the vaccines only cover a few of these - the ones
that have been linked to cancer. Vaccinated men and
women can still be infected with HPV strains that are
not covered by the vaccine.
If older men and women receive the HPV vaccine, there
is a risk that they have already been infected with
the strains of the virus that the vaccination covers.
If this is the case, they risk developing precancerous
cell abnormalities, even though they have been vaccinated.
HPV testing is advised for all women over the age of
30, even if they have received the vaccination.
HPV vaccination is not recommended for pregnant women.
The effect on fertility of the vaccine in the long-term
is not yet known although no adverse effects are expected.
As the HPV vaccine is relatively new, there is no data
to support its effectiveness in preventing cervical
and other cancers in the long-term. There is still insufficient
education around the issue of HPV vaccine and, because
of this, many girls are not receiving it because of
cost, inconvenience or moral issues.