Scientists are developing a vaccine
for people already infected with HPV, or the human papillomavirus, which is the
leading cause of cervical cancer.
The virus, which can also lead to
head and neck cancers, affects both men and women.
Dr. Sara Pai of Johns Hopkins
University School of Medicine, who visited Cayman last week to speak with
medical professions and members of the public about HPV vaccinations and treatments,
is part of a team who has developed the vaccine that boosts the immune system
to kill off cancer cells caused by the virus.
“A lot of people are infected with
HPV and don’t even know it,” Dr. Pai said.
While many people associate HPV
with cervical cancer, over the last decade it has become apparent that the
virus also leads to head and neck cancers, because the virus can attack the
tonsils. It often remains undiagnosed until the late stages because it is
difficult to detect and there is no blood test for HPV.
Dr. Pai said that her team has
already started vaccinating people with HPV-related cancer lesions, having
completed clinical trials last year. That vaccine is available for both men and
women with head and neck cancers related to HPV. The vaccine, she says, works
by boosting the immune system to recognise and destroy the cancer cells that
chemotherapy or radiation may miss.
However, head and neck tumours are
highly treatable with chemotherapy and radiation and there is a high recovery
They also plan to begin vaccinating
people who are infected with HPV, but do not yet have cancer, in spring 2011.
As well as developing a vaccine for
people who already have HPV, Dr. Pai and her team are working on finding an
early screening test for head and neck cancer.
”The mouth and throat are really
hard to examine for patients who are not diagnosed until the cancer spreads to
other areas of the head and neck. We are trying to develop early screening,
like with Pap smear for cervical cancer. We’re trying to develop an oral
screening test,” she said.
Dr. Pai, an assistant professor at
Johns Hopkins who specialises in head and neck cancers, explained to attendees
of a public seminar held during Gynaecological Cancers Awareness Month at
Savannah Primary School what steps they can take to find out if they are
infected with the HPV virus.
For women, this can be done through
Pap smears, which can detect abnormal cells in the cervix. If those are caught
early enough, they can be removed before the virus causes cancer. There is
currently no approved test for men, although the preventative vaccination,
Gardasil, is available for men.
The doctor also addressed concerns
raised about how safe the HPV vaccine is. Since it is a relatively new vaccine
– Gardasil, which is used in Cayman, was licensed by the US Food and Drug
Administration in 2006 – the long-term impacts and effects are not known. Since
it was approved, more than 29 million people in the US have been vaccinated
But Dr. Pai said that for now the
only side effects being seen are occasional pain and swelling at the injection
site and some reports of nausea and fainting, as is also seen as a result of
other vaccines. She added that her long-term concern about the vaccination was
the determination of how long it would last. “If anything, I’d be concerned
about how long the protection will last. We don’t know when they’ll need a
booster,” she said.
During her visit to Cayman, Dr. Pai
also held a talk with physicians and other medical professionals at the Cayman
Islands Hospital in George Town.
Through a partnership between the
Cayman Islands Cancer Society and the Health Services Authority, the HPV vaccination
was made available for free to girls ages 11 to 17, with that programme ending
in July. The vaccine is also available from private doctors for people between
ages 9 and 27.
Two strains of the virus are
attributed to causing 70 per cent of all cases of cervical cancer – the fifth
leading cause of cancer death among women and one of the most commonly diagnosed
cancers in Caribbean women. The HPV vaccine works on these two strains as well
as another two strains that cause 90 per cent of all cases of genital warts.