I remember when Gardasil was first introduced and the related controversy. I believe there were questions about its safety because at first it was targeted at 12 year old females. At one point the Japanese Ministry of Health suspended the vaccine and then later resumed it.
For me the explanation of how this vaccine works still confuses me. For example while older people are advised to get Shringix to mitigate the consequences of a reactivated chickenpox virus. Older are advised not to get Gardasil because once you get HPV, the vaccine is ineffective?
It was first largely triage. It had the highest odds of saving lives for young people and especially young girls. As more and more of the younger groups have been covered, the age recommendation has kept rising. At the same time the number of strains covered have gone up and that has also made it more worthwhile to vaccinate older groups.
It's also down to evidence. It's not that the vaccine has been proven to be ineffective, but that the vaccine had not been proven to be effective enough to be worth it for older groups initially, in large part because it was not what they tested for.
As I understand it from talking with a healthcare worker it isn't so much that it's less effective if you already have the infection (though it is) it's more just a triage decision.
People in various health care systems around the world have just done a cost benefit analysis and decided that it isn't worth paying for the vaccine for older people, that we'll just let them get cancer and go through treatment/die.
The other confusing thing is the benefit to risk ratio. Looking at the WHO rates of cervical cancer for Canada with almost complete vaccination rate vs Japan with almost zero vaccination rate, you can argue the vaccine cuts cervical cancer by 2/3. But when you look at the numbers at a per annual basis, the probability of getting cervical cancer is 0.5 percent to 1.5 percent.
For me the explanation of how this vaccine works still confuses me. For example while older people are advised to get Shringix to mitigate the consequences of a reactivated chickenpox virus. Older are advised not to get Gardasil because once you get HPV, the vaccine is ineffective?
https://mainichi.jp/english/articles/20211115/p2a/00m/0op/00...