I ve tried to hunt for many answers, with relation to HPV and Cervical cancer and where this Vaccine stands.
I ve come to a sort of closing conclusion to this discussion:
1. Of 1000 cervical cancer cases, there will be evidence of some HPV infection in 997 cases.
2. Of these 1000 cases, there will be evidence of HPV 16 and/or 18 in nearly 700 cases.
3. We don’t know what percent of virus infections don’t lead to cervical cancer. Without this figure, its impossible to know the NNT to prevent one case of cervical cancer
4. For every 18 or 19 women who get vaccinated, one case of HPV-16 infection will be prevented. Considering HPV-18 as well, you would need to vaccinate even fewer women, to prevent one case of infection by HPV-16 or -18. Then there is cross immunity, which means vaccination with one type of HPV protects you from HPV of other type.
5. The only immediate way to test the effectiveness of the vaccine was to have the freedom from HPV infection as the endpoint. Since there is a lead timebias of HPV infection leading to cervical cancer in 10 years, it is hoped that vaccine would prevent cervical cancer as it has so far been shown to be effective at preventing HPV Types 16 & 18 by 92%.
If the end point would have been to prevent one case of cervical cancer or preventing one death from cervical cancer, it would have taken the vaccine companies a few decades to meet the primary end point which would make the vaccine trial impossible to run.
There have been quite a few presumptions which have been made, like A = B = C+D = F+G-H = I -J x K = M x N + O-P=Z
and it is then hoped A equals Z. I agree the end points we are interested in right now, do not exist. But its a statistical probability that this vaccine will work based on the very little data we have which is A = B
This HPV virus is sexually transmitted . The ideal time for the vaccination is before a woman becmes sexually active and contracts the HPV infection. It is extremely difficult to know which girls are going to be sexually promiscous with multiple sexual partners or which unfortunate but faithful girl having a single partner (who cunningly has multiple partners) is going to develop HPV infection which will persist and lead to cervical cancer.
What seems most logical is to vaccinate the mass population in the hope to eventually reduce the incidence of cervical cancer. But of course this is going to be pretty expensive, but primary prevention was never cheap and is never going to be cheap.
Does anyone know the cost of Breast cancer screening via Mammogram in order to save one life ?
I will give you a few hints
1. You need 285 mammograms to diagnose one breast cancer.
2. 1666 ladies need to have regular mammography for 7 years to prevent one death from breast cancer.
http://www.annalsofian.org/article.asp?issn=0972-2327;year=2007;volume=10;issue=4;spage=225;epage=230;aulast=Prasad
What sense does this make ? For countries which can afford this— They will go for it
Those who cant afford — Those unfortunate women dont get mammograms
If you can pay such a heavy price for just simple EARLY DETECTION, what is the harm in paying for PRIMARY PREVENTION
So what if it takes 1000 or even 2000 women to be vaccinated with HPV to prevent one death from cervical cancers !
So how should a woman decide whether to get the Gardasil vaccine (or any vaccine), and how should parents decide whether to have their girls vaccinated?
There’s no one right answer for everyone. The statisical evidence is the starting point for discussions.
And of course, even if this vaccine were to save lives, you may not find it surprising that this vaccine will never be mandatory as part of a national immunisation schedule. It will remain voluntary. All what i can say is, you will read about these vaccines more and more as data matures. There will be meta-analyses on these vaccine trials as well. More pharmaceutical companies will try to manufacture them and the costs will decrease over a period of time at which point you may or may not use it.
