Question: A few of my married female friends have been told by their doctors to get the Gardasil 9 vaccine to prevent cervical cancer. We’ve all heard about the benefits of teens getting vaccinated, but it’s news to me that older people might need it. Should I get it, too?
Answer: It’s certainly true that there’s been a big push by public health officials to inoculate adolescents before they become sexually active. But the vaccine isn’t only for teens.
Here’s what you need to know: Gardasil 9, the most widely-used brand of the vaccine, guards against nine different types of the Human Papillomavirus (HPV) which is spread through vaginal, anal and oral sex.
An infection can cause cellular changes that may lead to cervical cancer and other tumours affecting both females and males.
There are actually dozens of different types of HPV. The vaccine provides protection from the forms of HPV which are responsible for about 90 per cent of cervical cancers and a high percentage of throat, oral, penis, anal, vaginal and vulva cancers as well as genital warts.
However, for maximum effectiveness, you need to be inoculated before exposure to the virus. That’s why all the provinces offer free HPV shots to youth, starting around the age of 11 or 12.
Although eligibility for a publicly-funded shot is limited to young people, “it’s never too late to vaccinate for HPV,” says Dr. Nancy Durand, a gynaecologist at Sunnybrook Health Sciences Centre and associate professor at the University of Toronto.
The vaccine is typically delivered in three separate injections over a period of six months. (Those under age 14 get two shots.) Each shot costs about $200. Many private insurance plans will cover the bill.
Dr. Durand notes that Canada’s National Advisory Committee on Immunization “places no upper age limit on this vaccine, regardless of whether you have had a past history of exposure.”
About 75 per cent of Canadians will be infected with at least one type of HPV at some point in their lives. But it’s extremely unlikely that someone will have been exposed to all types of the virus covered by Gardasil 9. That means the vaccine can still provide protection against the types of HPV that an individual has not yet encountered.
Even so, why would older people in long-term monogamous relationships need the vaccine? After all, you might think, they are not being exposed to new types of HPV.
Unfortunately, that might be wishful thinking, says Dr. Durand. “You may be monogamous as far as you know. But you don’t always know what your partner is doing. New HPV exposures may be happening without your knowledge.”
Yet even if you are monogamous now, one sobering statistic tells us that more than 50 per cent of marriages end in divorce. The death of a spouse will also leave a person single.
So, there are various reasons why people seek new partners later in life and may encounter certain types of HPV for the first time. “You don’t know your future,” says Dr. Durand. “And we would prefer to vaccinate before HPV exposures happen.”
Of course, not all HPV infections result in a cancer or persistent genital warts. The immune system has the ability to inactivate the virus or eradicate it entirely from the body. “The clearance rate for this infection is close to 80 per cent in patients under the age of 30,” says Dr. Durand.
But as we grow older, the immune system becomes less effective at keeping the virus in check. It’s possible that an inactive infection can become active again, leading to abnormal cells that may slowly progress to cancer.
For reasons that are not fully understood, women seem have a better ability than men to clear HPV from their bodies, says Dr. Durand.
Aside from shielding us from new HPV exposures, ongoing research suggests the vaccine may also provide some help against existing infections, says Dr. Marc Steben, a family physician in Montreal and chair of the Canadian Network on HPV Prevention.
In particular, several studies have looked at women who have been treated for abnormal or “pre-cancerous” cells discovered through routine cervical-cancer screening – known as the pap test.
The women who received HPV vaccination during their care were less likely to have the abnormal cells re-appear and to require further treatment, compared to those who didn’t get a shot.
This suggests the vaccine “should be part of the treatment plan to prevent recurrence of infection,” says Dr. Steben.
Despite the potential benefits of the HPV vaccine, many doctors don’t recommend it to their patients. They often assume their patients are either monogamous or will balk at the price.
Dr. Durand believes patients should at least be informed of the option so they can decide for themselves.