Page 8 - Mecklenburg_Medicine_January-2018

Feature
HPV Vaccine: Why or Why Not?
ABy James B. Hall, MD
ccording to the Centers for Disease Control, presently
some 80 million Americans are infected with the Human
Papilloma Virus (HPV). Absent a re-infection, the
immune system is usually able to clear the virus within
6-12 months. There are some 200 sub-types of the HPV that have been
identified, but from the clinical perspective we know there are about 20
low-risk types (these include HPV 6 and 11, causative for venereal warts)
and about 20 high-risk types (these include HPV 16 and 18, which are
the most common genotypes associated with squamous cell cancers, as
well as some adenocarcinomas). This high-risk group has been found
to play a prominent role in the development of cervical, vaginal, vulvar,
penile and anal cancers; more recently HPV also has been associated
with oropharyngeal cancers.
It is remarkable, These oropharyngeal
cancers are five-times
and perhaps more common in men than
unconscionable, women and more common
in African-American men
that we have a than any other group;
vaccine that is very however, a recent report
effective and safe, from MD Anderson
and yet only about demonstrated that it is now
40 percent of those the fastest growing cancer in
young white men.
Clearly, this virus can
impact both men and
needing it have women and all ethnic
received the vaccine. groups. While this is
essentially an endemic
virus in humans, there is
a prevention. In 2006, the
Food and Drug Administration approved the first vaccines, Cervarix, a
GSK product, and Gardasil, made by Merck, for use in girls and young
women ages 9-26. Then, in 2010, there was FDA approval in boys and
young men, as well. Cervarix was a bi-valent vaccine against HPV 16/18,
and Gardasil was a quadra-valent vaccine against HPV 6/11 and 16/18.
HPV 16/18 have been identified as the causative agent in 70 percent
of squamous cell cancers. These explained the panoply of abnormal
Pap smears as precursors to cervical cancer. Logically, if vaccinations
occurred prior to exposure to these viruses, then one’s risk of developing
cancers caused by HPV 16/18 potentially could be eliminated. The initial
studies involved a three-shot regimen given at the time of the office
visit, then again two months later and six months later. This proved to
be cumbersome in that most patients either could not or did not return
to receive the complete regimen. Unfortunately, despite a national
education endeavor on the value of the vaccine, there is still only about
a 42-percent usage in targeted patients. But, fortunately, those numbers
are increasing, especially in young men, and yet there is still about a
20-percent difference in 17-year-old girls who have been vaccinated over
8 | January 2018 • Mecklenburg Medicine
boys. It has been problematic getting the three-shot regimen completed.
Even in patients who began the regimen, completion of therapy often
was not carried out. In recognition of this, and given the immunogenicity
of children, in 2016 the FDA approved and the Advisory Committee
on Immunization Practices recommended the adoption of a two-shot
regimen (time 0 and =/> 6 months +/- 4 weeks) in children up to 14
years of age, with the caveat that based on available data, those over 15
years of age are still recommended to use the three-shot regimen, and if
there is any history of immunocompromise, then the standard three-shot
regimen still is recommended. The good news is that more children are
getting vaccinated. In 2016, 60 percent of adolescents received one or
more doses of HPV vaccine, compared to only 30 percent a decade ago.
An interesting observation of Amy Middleman, MD, head of adolescent
medicine at the University of Oklahoma Health Sciences Center, was
that a secondary benefit now being observed in young women in their
early 20’s who had taken the vaccine as children, is the reduction of the
most dangerous strains of HPV by more than 30 percent.
The other important fact is that even though most of us are living in
the same geographical area (the United States), there now have been
noted different ethnic tendencies of infectivity. While HPV 16/18 are
most common in Caucasians, a study done at Duke demonstrated that
HPV 16/18 occurs in African-Americans at only about half the rate
that it does in Caucasians. Evaluation of CIN (cervical intra-epithelial
neoplasia) in African-Americans identified the more common genotypes
of HPV 33, 35, 58 and 68. As of 2016, a nine valent Gardasil was
approved and became the only available vaccine in the American
market. In addition to the previous four genotypes covered (HPV
6/11/16/18), the five additional that are covered include 31, 33, 45, 52 and
58. This then provides better coverage for the U.S. population.
Presently, the 9vHPV vaccine Gardasil is FDA-approved as prevention
for genital cancers. But, as of yet, it is not approved as a prevention for the
oropharyngeal cancers. The keyword here is “prevention.” To be effective,
one must be immunized prior to one’s exposure/”sexual debut;” hence, the
timing of the ACIP’s recommendation of immunization of 11- and 12-year-
olds. Remarkably, the only states that mandate HPV immunization are
Rhode Island and Virginia, as well as the District of Columbia.
Based on 2017 American Cancer Society statistics, the six cancer sites
covered by the HPV vaccine represent more than 83,000 new cancer
cases annually in the U.S. It is remarkable, and perhaps unconscionable,
that we have a vaccine that is very effective and safe, and yet only about
40 percent of those needing it have received the vaccine. This needs to be
a priority from a community health perspective, not to mention from a
health economics perspective (e.g., there are about 55 million Pap smears
done annually, and of these, about 5-10 percent are abnormal). Not only
could we potentially eliminate these cancers and the millions of dollars
spent treating them, but even more money is spent annually simply in the
evaluation of the millions of abnormal PAP smears, which potentially
also could be eliminated. In the words of the late Sen. Everett Dirksen, “A
billion here, a billion there, pretty soon you’re talking real money.”