Does the hpv vaccine ever expire? i have had it now for about 20 years. am i still protected? also when did they stop using the vaccine that only protected against two strains and moved to gardisil that protected against 4 strains?

There were 2 original HPV vaccines on the market in the 2000's, one covered only 2 strains involved in genital cancer, the other (G)covered 2 genital wart strains and 2 genital cancer strains. By 2014 the Gardasil covered 2 wart and 7 genital cancer strains. Market use led to the end of production of the early 2 strain vaccine. We will need decades of use to be sure of how long protection lasts.

Gardasil covering 4 strains was approved in 2006. Since 2016, only Gardasil protecting against 9 strains has been available in the US. HPV vaccination is generally not necessary for people older than 26 due to past HPV exposure. But some may benefit, so the best decision can be made with a doctor who knows a person’s health history. More studies are needed to determine how long protection lasts.