article last week in BMJ from Australia finding that HPV vaccination in females led to decrease in high grade cervical abnormalities (see doi: 10.1136/bmj.g1458). not an RCT, but a case-control study “real-world” study to see if effect of prior vaccination on first cervical screen. results:
–females offered free quadrivalent HPV vaccine aged 12-26.
–at time of first pap smear, high grade cases in 1062 women, “other cases” (any other abnormality) in 10,887, and normal cytology (controls) of 96,404
–odds ratio for exposure to 3 doses of HPV vaccine vs no vaccine 0.54 for high grade cases and 0.66 for “other cases”, vs controls (ie vaccine effectiveness of 46% and 34%, with number needed to vaccinate being 125 and 22 respectively)
–if got only 2 of the 3 shots for vaccination, odds ratios of 0.79 for both high grade as well as for “other cases” (ie, vaccine effectiveness of 21% for each)
–on further analysis of their data,
–effectiveness of vaccination was not even close to being significant in the oldest age stratum (age 23-27)
–standard pap smears done at that time (2007-2011) first done between age 18-20 in sexually active women, or 1-2 years after first sexual intercourse, whichever is later
–of the 1062 high grade abnormalities, 7 were invasive squamous cell ca, 944 CIN 3, 84 CIN 2, 1 adenoca microinvasive, and 11 adenoca in situ
–1/3 of paps done age 15-18, 1/3 age 19-22 and 1/3 age 23-27
so, i bring this up mostly because of the strong title of the article and that it seems to be getting some play in the press. not sure how really useful it is, given that most of the patients were under 22 (and we stopped doing pap smears before age 21 given the very high number of HPV-related abnormalities, the vast majority of which spontaneously regress), and perhaps as confirmation of that, there was no difference in effectiveness of vaccine for high grade cases in those 23-27 years old. there are some similar data from the US finding 50% decrease in HPV types 16,18,6,11 in young women aged 14-19 (again, younger than we are testing with paps) and even in young women for oral HPV 16/18 infection. though it is concerning that there were several cancers (but very low %) in this young group…..
geoff