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Revisiting the HPV vaccine
Feb. 1st, 2007 10:08 amDoes the HPV vaccine really work?
I've been meaning to look into this since I had a conversation with a very sexy doctor friend (*winks*) about the pros and cons of Gardasil, the HPV vaccine.
The conversation called the efficacy of the vaccine into question, which left me wanting to learn more about how they tested the vaccine, both for safety and efficacy.
Here's what I found:
- in women ages 9-26, they found that the vaccine induced "high and persistent anti-HPV antibody titres"
- they followed more than 20,000 women who had been administered the vaccine for two years, and found "the vaccine was highly effective in preventing cervical dysplasia of any grade and external genital lesions related to HPV types 6, 11, 16 and 18 infection."
http://www.ingentaconnect.com/content/adis/dgs/2006/00000066/00000009/art00008
Sounds fair enough, except for the fact that the incubation period is MUCH longer than 2 years.
"The incubation period for HPV 16 to give rise to cervical cancer is quite long and rather variable. It has been estimated that among HPV 16-positive women, the median incubation period from first detected HPV infection to cervical carcinoma in situ was between 7 and 12 years."
http://www.stanford.edu/group/virus/papilloma/2004goglincarnevale/Papilloma/HPV16.htm
I was unable to find the incubation period for the other three strains... but how can they claim to be effective after only following these women for two years, when one of the strains they are claiming to prevent has an incubation period of 7 to 12 years... I couldn't say. It seems rather ridiculous. (I'm wondering if there are separate incubation periods, and they are talking about different ones here... even so, progression to SIL, which is the next stage towards cervical cancer, takes about 5.6 years on average, which barely puts them in the zone for the HPV-16 vaccine... IF that's what these numbers mean.)
And, like with all approved drugs, we know that the short term safety is good, but we don't know what the long term safety is, and won't know until it has been on the market for a good long time.
I'm not saying that the vaccine WON'T protect you. But I AM saying that you don't know for sure, and we won't for another decade or so.
Given the cost of the vaccine, I know I'm going to have to think carefully about whether or not to get it. In the long run, I imagine it will afford some resistance to HPV, which seems worthwhile for someone like me. But there is no guarantee.
I've been meaning to look into this since I had a conversation with a very sexy doctor friend (*winks*) about the pros and cons of Gardasil, the HPV vaccine.
The conversation called the efficacy of the vaccine into question, which left me wanting to learn more about how they tested the vaccine, both for safety and efficacy.
Here's what I found:
- in women ages 9-26, they found that the vaccine induced "high and persistent anti-HPV antibody titres"
- they followed more than 20,000 women who had been administered the vaccine for two years, and found "the vaccine was highly effective in preventing cervical dysplasia of any grade and external genital lesions related to HPV types 6, 11, 16 and 18 infection."
http://www.ingentaconnect.com/content/adis/dgs/2006/00000066/00000009/art00008
Sounds fair enough, except for the fact that the incubation period is MUCH longer than 2 years.
"The incubation period for HPV 16 to give rise to cervical cancer is quite long and rather variable. It has been estimated that among HPV 16-positive women, the median incubation period from first detected HPV infection to cervical carcinoma in situ was between 7 and 12 years."
http://www.stanford.edu/group/virus/papilloma/2004goglincarnevale/Papilloma/HPV16.htm
I was unable to find the incubation period for the other three strains... but how can they claim to be effective after only following these women for two years, when one of the strains they are claiming to prevent has an incubation period of 7 to 12 years... I couldn't say. It seems rather ridiculous. (I'm wondering if there are separate incubation periods, and they are talking about different ones here... even so, progression to SIL, which is the next stage towards cervical cancer, takes about 5.6 years on average, which barely puts them in the zone for the HPV-16 vaccine... IF that's what these numbers mean.)
And, like with all approved drugs, we know that the short term safety is good, but we don't know what the long term safety is, and won't know until it has been on the market for a good long time.
I'm not saying that the vaccine WON'T protect you. But I AM saying that you don't know for sure, and we won't for another decade or so.
Given the cost of the vaccine, I know I'm going to have to think carefully about whether or not to get it. In the long run, I imagine it will afford some resistance to HPV, which seems worthwhile for someone like me. But there is no guarantee.
