Transforming and integrating STI surveillance to enhance global advocacy and investment in STI control

`Sexually transmitted infections (STI) exact an astounding yet preventable toll on the health and lives of men and women worldwide. The World Health Organization (WHO) estimated 376 million new curable STI occurred in 2016, including chlamydia (127 million), gonorrhoea (87 million), syphilis (6.3 million) and trichomoniasis (156 million) 1. More than 500 million people were estimated to have genital infections with herpes simplex virus (HSV-1 or HSV-2) in 2012 2. Approximately 290 million women were estimated to have a human papillomavirus (HPV) infection in 2007 3. These infections have predictably serious complications for the men and women infected and their new-born infants. More than 500,000 incident cervical cancer cases, caused by HPV occurred in 2018, with a greater than 50% mortality rate 4. For 2016, WHO estimated 988,000 pregnant women were infected with syphilis resulting in 660,000 congenital syphilis cases of which 350,000 were adverse birth outcomes including stillbirth and neonatal death 5. Additional STIs such as viral hepatitis, Mycoplasma genitalium infection, and lymphogranuloma venereum add further weight to these estimates 6, 7. Newly emerging viral pathogens Ebola and Zika have gained prominent attention as they are each sexually transmitted. 8, 9 STI have been associated with increased HIV transmission 10, 11. Yet while remarkable progress has been made in reducing HIV transmission and improving lives of patients with anti-retroviral therapy (ART), STI incidence is high and increasing in many regions 1 (Figure 1). Although antiretroviral pre-exposure prophylaxis (PrEP) is associated with reduced HIV transmission, STI incidence tends to be high among PrEP patients, as well among persons living with HIV and other vulnerable populations 12-14. The biological and behavioural links between HIV and STIs suggest opportunities for improving STI control and surveillance through existing HIV prevention, testing, and treatment services. In 2016, three linked WHO strategies for HIV, hepatitis and STIs were endorsed by the World Health Assembly 6, 7, 15. Each of these strategies called for integration across fields of surveillance and service delivery for these three infection groups. Robust national-level strategic information systems that incorporate STI case reporting, prevalence surveys, assessment of the aetiology of STI syndromes, and monitoring for antimicrobial resistance to gonorrhoea are needed to guide programming and clinical service delivery 7, 16 (Box 1). As reported in this issue by Wi et al., most countries lack the basic capacity to diagnose and treat STIs let alone implement surveillance 17. Yet potential stakeholders must first recognize the prevalence and impact of these infections from reliable surveillance data. A vicious cycle of limited STI surveillance and narrow STI program response continues in most resource limited settings. Countries need strong strategic information systems that incorporate STIs to inform and help target prevention and treatment efforts, to rally political commitment, and build a strong national investment case. It is essential for countries to know their STI epidemics and to know the recommended responses in order that up to date, accurate information can guide national programming. WHO has developed frameworks, targets and priority actions for STI surveillance at national and global levels 7, 16, 18 (Box 1). Global strategic information systems like the UNAIDS Global AIDS Monitoring system (GAM) 19 have helped to align national-level reporting of key STI indicators related to syphilis and gonorrhoea alongside those of HIV, but reported data are incomplete and many countries are challenged to collect verifiable data. WHO has supported the development of freely available modelling tools such as Spectrum STI 20 and the WHO congenital syphilis estimation tool 21 to allow the use of country-reported data to conduct national-level analysis of incidence and prevalence trends. WHO conducts global surveillance for antimicrobial resistance in gonorrhoea, which captures proportions of resistant organisms from nearly 60 countries 22. High-income and low-middle income countries with STI surveillance systems frequently rely on case reporting of STI cases or STI syndromes to estimate national incidence 23-26. Case reporting drastically underestimates the burden of STIs due to the asymptomatic nature of infection, limited access to care for those with symptoms, and limited provider reporting 18. For these reasons, case reporting alone would not be a reliable measure of national STI burden. National, regional and global incidence and prevalence can be derived from longitudinal STI prevalence surveys using standard methods 18. STI prevalence surveys among general and high-risk population groups of men and women can be conducted as part of population-based health surveys such as those done for HIV, or in association with other health surveys or health services such as HIV screening and prevention (PrEP), maternal, reproductive, adolescent and child health services and military, work-related or school-based health screening. As STIs are not equally distributed among sexually active populations and a disproportionally higher burden of the STI/HIV epidemic occurs among certain key population sub-groups, such as men who have sex with men and sex workers, specialized surveillance and culturally tailored programmes to address STIs among these populations are warranted. Routine STI prevalence assessments can identify key populations that can benefit from the implementation of effective STI interventions and further provide evidence of their impact. Global, regional and national estimates of STIs suffer from limited prevalence surveys among general populations, particularly among men 1. It is evident from recent global and regional estimates of STIs that the necessary stakeholder support, advocacy and investment – both national and international – to support STI programme and surveillance efforts has not been realized. While the burden of prevalent and incident STI cases increases, advocacy for control of these infections has waned. Transforming and strengthening STI surveillance and clinical services can serve as a cornerstone for advocacy and investment in STI prevention and control. Alignment of STI control programmes alongside HIV and hepatitis prevention through linked WHO strategies has offered frameworks for integration yet clinical services and surveillance of STIs continue to lag behind 27. As part of a transformation process taking place at WHO, set in motion by the Director General in 2018, the global STI surveillance and STI programme support activities will be moved from the WHO Department of Reproductive Health and Research (WHO RHR) to the Department of HIV and Hepatitis, to be duly renamed the WHO Department of HIV, Hepatitis and STIs. STI research will remain with (WHO RHR) ensuring that research continues to inform STI programming. The move of the STI programme will set an example at the global level of the opportunity to integrate these surveillance and country support activities recognizing similar modes of transmission, populations at risk and currently existing health care platforms. This transition is expected to herald a renewed global focus on the importance of STIs as indicators of HIV and hepatitis risk and as opportunities for prevention and control of all STIs while ensuring continued inclusion within the broader framework of sexual and reproductive health and rights 28. The authors have no competing interests to declare. MT and TW conceived of the paper and provided content and references. MT drafted the paper. MT and TW reviewed and revised drafts prior to submission Jane Rowley and Eline Korenromp for their contribution to global STI estimation. Francis Ndowa for support of STI surveillance strengthening at national level; Nathalie Broutet, Sami Gottlieb, Igor Toskin, James Kiarie and Ian Askew for commitment to global STI surveillance programming. UNAIDS and the WHO HIV and Hepatitis Department for support of integrating global STI surveillance within HIV surveillance systems. The project was funded by the World Health Organization, Department of Reproductive Health and Research, STI programme and furthermore supported by a cooperative agreement from the U.S. Centers for Disease Control and Prevention in support of strengthening STI surveillance. The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the World Health Organization, or the U.S. Centers for Disease Control and Prevention.