Vaccine hesitancy
is hardly limited to shots against
COVID-19. Even the HPV vaccine, which can
prevent as many as 90 percent of six potentially lethal cancers, is meeting
with rising resistance from parents who must give their approval before their
adolescent children can receive it.
اضافة اعلان
The
Food and Drug Administration licensed this lifesaving
vaccine in 2006 to protect against sexually transmitted infection by HPV, the
human papillomavirus. Most of us will get infected with HPV during our
lifetimes, certain strains of which can lead to cancers of the cervix, vagina
and vulva in women; cancers of the anus and back-of-the-throat in both women
and men; and penile cancer in men. HPV can also cause genital warts.
But the vaccine only works if it’s administered before people
become infected by the virus. And that often means getting vaccinated
before teens and young adults have any form of sexual activity.
Unless they are vaccinated, more than 80 percent of women
become infected with HPV by age 50. And while most infections clear on their
own, enough persist to cause many thousands of cancers years later. There is no
treatment for an HPV infection.
Yet
Kalyani Sonawane, a researcher at the
University of Texas Health Science Center, and her colleagues reported in March that parental
intent not to vaccinate their adolescents against HPV rose from 50.4 percent in
2012 to 64 percent in 2018. Many parents resisted the vaccine despite their
doctors’ recommendations, Sonawane said. Ironically, parents were most
resistant — at 68.1 percent — to vaccinating girls, the very group for whom
this vaccine was initially developed to prevent cervical cancer.
Now, if not for the slow adoption of the HPV vaccine by the
parents of adolescents, we would likely be well on our way to eliminating nearly
all cases of cervical cancer and the five other HPV-caused cancers, 45,000
cases of which are diagnosed annually in the US, Dr. Abraham Aragones, a public
health researcher at
Memorial-Sloan Kettering Cancer Center told me.
A highly effective vaccine
Until recently, the vaccine’s ability to prevent cancer was
presumed but not proved. Cervical cancer risk rises with age, most often
occurring in midlife or later, so it can take many years to confirm the
vaccine’s ability to protect against cancer.
Now a new study in Britain of an early version of the
vaccine found that within 13 years of vaccine administration, there were 87
percent fewer cases of cervical cancer among young women immunized between ages
12 and 13, compared to unvaccinated women. Significantly lower cancer rates
were also found among women immunized between ages 14 and 16 and between 16 and
18, although the greatest benefit occurred among those vaccinated at the
youngest ages, before most girls were likely exposed to the virus through sexual
contact.
(Illustration : Envato-Elements)
The British study involved a vaccine called Cervarix that
protects against two variants of the virus. The current US version of the HPV
vaccine, called Gardasil-9, is even more effective: It protects against nine
variants of the virus and is expected to prevent more than 90 percent of
HPV-related
cancers, Aragones said. A recent analysis in JAMA Pediatrics found
a similar decrease in cervical cancer incidence and mortality in young women
since the vaccine was introduced.
Based on a steadily declining incidence of cervical cancer
and a high rate of vaccine coverage in Australia, researchers there predicted
that the country would have fewer than four new cases of cervical cancer per
100,000 women by 2028 and virtually none by 2066.
To be sure, regular Pap smears that detect precancerous
cervical lesions have helped greatly to prevent the development of invasive
cancer, but early detection efforts do not fully eliminate the risk of cervical
cancer. This year, the
American Cancer Society estimates that 14,480 new cases
of invasive cervical cancer will be diagnosed in the US and about 4,290 women
will die from it. And there is no screening test like the Pap smear for the
other five HPV-caused cancers.
Parents’ buy-in remains the biggest obstacle
Once the real cancer culprit was identified as the human
papillomavirus and a vaccine to prevent it finally developed, persuading
parents to have their young daughters immunized has been an uphill battle for
practitioners. Few have the time and factual ammunition to counter parental
fears and misinformation about this vaccine.
Getting parents to agree to immunizing boys has faced an
additional obstacle. The original approval of the vaccine to prevent cervical
cancer prompted many parents to question its value for boys, for whom the
vaccine was approved three years later. Parental resistance to immunizing their
sons rose to 59.2 percent in 2018, up from 44.4 percent just six years earlier
“Parents and providers don’t necessarily appreciate the
burden of HPV-caused cancers among men,” said Dr. Dean A. Blumberg, chief of
pediatrics at
UC Davis Children’s Hospital. “Oral-pharyngeal cancer rates are
almost five times higher in men than in women, and they’ve increased in recent
years with the rise in oral sex. The vaccine is important for the boys to
protect their own health and the health of their future partners.”
(Illustration : Envato-Elements)
How the vaccine is administered
Between ages 9 and 15, two shots of HPV vaccine are
required, administered six months apart; from age 15 on, three shots are needed.
Side effects are usually mild, like pain or swelling at the injection site and
perhaps brief fever, fatigue, nausea or muscle pain. The vaccine’s cost is
nearly always covered by insurance.
Sonawane said parental misconceptions about the vaccine’s
safety are commonplace, and doctors rarely have the time to debunk vaccine
misinformation parents find online. “Positive information about vaccines
doesn’t get posted on social media,” she observed.
Some parents fear that immunizing their children against HPV
will encourage them to engage in sexual activity, although there is no evidence
this happens. Aragones, among others, suggested that the best way for doctors
to minimize parental opposition is to describe the vaccine’s anticancer role,
limit discussing the link to sexual activity and include the immunization with
the other vaccines that are routinely given to adolescents.
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