Can someone who is intelligent explain this to me
Hey guys, I would have posted this in the sexual health forum, but I still don’t have permission to post there (how many posts does it take?). Anyway, I was reading up the study done in Africa in which they circumcised one group and didn’t circumcise the other and studied the effects on HIV, herpes, and HPV. Here is the link (http://content.nejm.org/cgi/content/full/360/13/1298). What I don’t understand is how they get the final statistics from the ones discussed after each STD analysis.
They claim “The cumulative probability of HSV-2 infection during the 24-month period was 7.8% in the intervention group, as compared with 10.3% in the control group,” and then, “In the primary intention-to-treat analyses at 24 months, high-risk HPV genotypes were detected in 42 of 233 subjects in the intervention group (18.0%), as compared with 80 of 287 subjects in the control group (27.9%).”
Okay that seems fine, but then in the Discussion they say:
“The efficacies of circumcision for the prevention of HSV-2 incidence and HPV prevalence were 25% and 35%, respectively. Adjustment resulted in a modest increase in efficacy to 28% for HSV-2 infection but did not change efficacy for HPV infection.”
The herpes breakdown is the one I don’t understand the most. How did they go from 2.5% higher chance of getting herpes in the analysis to 25% in the discussion?