Samkange-Zeeb et al. BMC Public Health 2011, 11:727 http://www.biomedcentral.com/1471-2458/11/727 Page 6 of 12 Table 2 Characteristics of the 15 studies on knowledge on sexually transmitted diseases among school-attending ado- lescents in Europe (Continued) Höglund et al. Uppsala, [47] Sweden Not Classroom- Knowledge of and available completed attitudes to STDs, questionnaire focus on HPV Pelucchi et al. Milan area [48]*** and Varese, Italy 2008 Sachsenweger Mecklenburg- 2005 et al.[49]# Western Pomerania, Germany Home- completed questionnaire Classroom- completed questionnaire Knowledge of HPV, prevention, and attitudes towards vaccination Knowledge on HIV/ AIDS 15-20 years 459 year 1 of upper secondary school pupils 14-20 years 863 high school pupils Male/ female Male/ female 5 schools 8 schools 98% 79% 11-18 years 769 year 7-9 Male/ pupils female Not clear how many schools participated Not available * Other part of study conducted in Kenya. Only Swedish part reported on and included in this review. ** Focus group discussions also held with local teenagers. Only details pertaining to questionnaire survey reported on and included in this review. 1,2 Publication reported on two separate studies. In both school children were compared to shelter children. Only details pertaining to school children are reported on and included in this review. *** Questionnaires also sent to parents. Only details pertaining to adolescents reported on and included in this review. #Publication in German. participation rates, 7 had participation rates ranging from 79% to 100%. The remaining two studies had par- ticipation rates of 21.5% and 58% (Table 2). Six STDs were focussed on in the studies included in the review, with awareness and knowledge being assessed in depth mainly for HIV/AIDS and HPV, [36,41-43,46-49] and to some extent for chlamydia [37,38,42,47]. For syphilis, gonorrhoea and herpes, only awareness was assessed in four studies [37,38,42,47]. Awareness and knowledge of HPV The reported awareness of HPV among the surveyed adolescents was generally low (identification from given list), ranging from 5.4% in the study by Höglund et al. [47] to 66% in the study by Pelucchi et al. [48]. In the two studies which also reported results for females and males separately, awareness was observed to be statisti- cally significantly higher among females than among males: 16.4% vs. 9.6% in the Swedish study by Gottvall et al. [46] and 71.6% vs. 51.2% in the Italian study by Pelucchi et al. [48]. In the study by Höglund et al., only one of the participating 459 adolescents mentioned HPV (in response to an open question on known STDs) [47]. Awareness of the HPV vaccine was also very low, with 5.8% and 1.1% of adolescents surveyed in the studies by Gottvall et al. and Höglund et al. respectively, reporting being aware of the vaccine [46,47]. Whereas only 2.9% and 9.2% of adolescents in these two Swedish studies were aware that HPV is sexually transmitted, the proportion was 60.6% in the Italian study [48]. A minority of adoles- cents knew that HPV is a risk factor for cervical cancer: 1.2% in the study by Höglund et al. [47] and 8.1% in the study by Gottvall et al. [46]. Among the adolescents who participated in the survey by Pelucchi et al., 48.6% were aware that the aim of the HPV vaccine is to prevent cervi- cal cancer [48]. Among female adolescents who partici- pated in the study by Gottvall et al., 11.8% did not believe they would be infected with HPV [46]. The proportion was 55% among female participants in the study by Peluc- chi et al. [48]. The latter study surveyed pupils aged 14-20 years but did not report on age differences in awareness. Three studies reported on awareness of condylomata, genital warts which are caused by the human papilloma virus. Two of the studies reported awareness of 35% [38] and 43% [37]. The third study mentioned that awareness of condylomata was lower than that for chla- mydia without stating the corresponding figures [40]. Awareness and knowledge of HIV/AIDS Knowledge and awareness was quite high in all studies reporting on HIV/AIDS, with more than 90% of adoles- cents being able to identify the disease as an STD from a given list or in response to the direct question “Have you ever heard of HIV/AIDS?” [36,38,42]. In one study where the open question “Which STDs do you know or have you heard of?” was used, 88% of respondents mentioned HIV/AIDS [47] (Table 3). In the studies where this was asked, a large majority of the adolescents knew that HIV is caused by a virus, [36,41] is sexually transmitted, [36,41,43,47,49] and that sharing a needle with an infected person may lead to infection with the virus [36,41,43,49]. Statistically signifi- cant age specific differences in knowledge on mode of HIV-transmission were reported in the study conducted in Germany [49]. Compared to 13 and 15 year old pupils, a higher proportion of 14 year old pupils correctly identi- fied the level of risk of HIV-transmission associated with bleeding wounds, intravenous drug use and sexual