Currently the HPV (human papilloma virus) vaccines are approved in the United States up to the age of 26. This has nothing to do with safety but due to the fact that the studies submitted to the Food and Drug Administration (FDA) involved this age range. The HPV vaccines were primarily studied in women aged 26 years and younger because age is a significant factor in acquiring HPV. If you want to show that your vaccine can help people you need to study as many of your target population as possible. You also need to make translating your work to the general population practical – doing antibody levels to see who is immune isn’t is an expensive barrier so age became the proxy.
The peak risk of acquiring cancer causing HPV is under the age of 25 so the younger the women the more likely the vaccine will be given before exposure to HPV occurs. That’s why targeting 11 and 12-year-old is important. In addition, the immune response to the vaccine may be more robust around age 11 or 12. However, what if you are 27 and for whatever reason never got vaccinated against HPV or are 38 and the vaccine didn’t exist when you were in the target age range? Could the HPV vaccine be helpful for women over the age of 26?
New data looking at antibodies in the blood against HPV tells us that the risk of having either HPV 16, 18 (the most cancer causing types) or both over the age of 30 is 24% for women with a history of normal pap smears. For those with a history of high-grade dysplasia the risk of having one or both of the viruses jumps to 44%. The highest risk age group for HPV 16/18 is ages 30-39 years – 33% of women in this age range will be positive and if they have a history of high-grade dysplasia it rises to 55%.
The risk of HPV declines after 39, no one know if the natural antibody levels simply drop or if this is due to different cumulative sexual practices in older women (one study shows that antibody levels to HPV 16 don’t decrease with age).
In the study I linked to above the biggest modifiable risk factor for HPV 16 or 18 was the number of sexual partners – three or more lifetime partners increased the risk six fold. A history of having Chlamydia (a sexually transmitted infection) almost doubled the risk.
It’s easy to see why governments looking for the best impact for each public health dollar have focused on ages 11 and 12. If you get everyone before they are sexually active then everyone can benefit. But what about you as an individual?
There is nothing wrong with getting the HPV vaccine over the age of 26, although in most countries that will mean you have to pay for it yourself. It just means the older you are the less likely you will get the full protection as the risk increases with age that you have already been exposed. Women over the age of 26 who are most likely to benefit would never have had an abnormal Pap smear, have no history of Chlamydia, and have less than three lifetime sex partners. However, 45% of women between the ages of 30 and 39 with a history of high-grade dysplasia will still be negative for HPV 16 and 18 and so almost half will get protection from the HPV vaccine. Australia, a real leader in the fight against HPV, recommends the vaccine for women up to the age of 45. If you want to eradicate the virus getting as many people covered as possible is the way to go.
Given the new vaccine covers nine types of HPV there is a greater chance that more women over the age of 26 regardless of sexual history will get some protection, but whether it’s will be worth the $390 is an individual decision. Since two doses seems to be as effective as three a strategy for women over the age of 26 who are paying out-of-pocket might be to consider 2 doses (which currently costs $260).
However, until we can improve vaccination rates among adolescents in the United States there will be a steady stream of women who have to try to figure out if they want to spend their money on the vaccine or take their chances.