[Adolescents' affectivity and sexuality: a randomized trial of the efficacy of a school health promotion intervention in a primary school].

A cluster randomised trial was conducted to evaluate the efficacy of a health promotion intervention aimed at improving knowledge and preventing sexually transmitted diseases (STD) amongst Grade 9 primary school students in Salerno (Italy). Students were randomized to either one of two groups: intervention group or control group. The intervention group was required to attend three meetings, each lasting one and a half hours.