A combination approach of behavioural and biomedical interventions for prevention of sexually transmitted infections

The World Health Organization (WHO) estimated that in 2016 the global annual incidence of chlamydia, gonorrhoea, trichomoniasis and syphilis among people 15 to 49 years of age was 376.4 million infections.1 The increased number of etiological pathogens known to be sexually transmissible, such as Zika and Ebola viruses, new outbreaks of acquired and congenital syphilis and Lymphogranuloma venereum, increasing antimicrobial resistance in Neisseria gonorrhoeae and potential resistance in other sexually transmitted infection pathogens, such as Treponema pallidum and Mycoplasma genitalium, raise additional concerns.2 Facing a global epidemic of sexually transmitted infections, the international public health agenda now emphasizes the importance of strengthening the control of such infections, including human immunodeficiency virus (HIV), through a combination prevention approach. This approach consists of the simultaneous use of rights-based, evidence-informed and complementary behavioural, biomedical and structural interventions operating at individual, relationship, community and societal levels. The combination of behavioural and biomedical approaches to sexually transmitted infections and/ or HIV prevention is currently debated. Research and prevention programmes often give priority to biomedical approaches.3 Behavioural interventions have demonstrated effectiveness in reducing the incidence of sexually transmitted infections, including HIV, in various target groups and in a range of settings, whether these interventions are incorporated into combination prevention programmes or delivered separately.4–6 Several meta-analyses have shown that single-session behavioural interventions are as effective as more resource-consuming multisession intensive behavioural interventions for sexually transmitted infections and/ or HIV transmission.4,5,7 Clearly, the findings differ across studies, varying in terms of intervention type and length, theoretical foundation, setting and study design. Most of the studies were conducted in the United States of America and other high-income countries, suggesting the need to examine the role of combining behavioural with biomedical interventions for the reduction of these infections in lowand middle-income countries (Fig. 1).