Introduction
Herpes simplex virus type 2 (HSV-2) is the primary cause of genital herpes infection globally and is almost exclusively sexually transmitted.1 2 It is a lifelong, incurable infection affecting nearly half a billion people aged 15–49 and is considered of major public health significance.2 The infection is highly transmissible and may be associated with lifelong recurrence of symptoms, including severe pain, and is the predominant cause of genital ulceration worldwide.3 Serious complications include neonatal infection and meningitis.4 5 HSV-2 has been associated with the acquisition and transmission of HIV in HIV epidemic regions.6 Increasing evidence has found that persons with HSV-2 seropositive are up to five times more likely to acquire HIV, and persons living with HIV who become HSV-2 seropositive are more likely to transfer the virus to their sexual partners.7
The highest burden of HSV-2 has been reported in low-income and middle-income countries (LMICs), with women (313.5 million) being infected at a higher rate than men (178.0 million).2 Populations in Africa have the highest HSV-2 prevalence, followed by the Western Pacific, South-East Asia and Americas regions.2 There is an increased incidence of HSV-2 among populations with higher-risk sexual behaviours, for example, men having sex with other men (MSM) and female sex workers (FSW) compared with the general population.8 9
In 2001, in response to the substantial burden of HSV-2 and a growing body of evidence linking HSV-2 to HIV prevalence and incidence, the WHO hosted a 3-day workshop to set research priorities for HSV-2 in LMICs.10 Setting health research priorities is essential for optimised use of research resources.11 12 This is particularly important for resource-poor countries. Priorities are best developed through the application of defined methodologies by multiple stakeholders, including researchers, policy-makers, healthcare providers and service users.13 The workshop brought together a broad range of regional and disciplinary expertise. The participants were from Europe (n=18), Africa (n=10), North America (n=7) and Asia (n=1). Their expertise spanned areas of biochemistry, clinical medicine, programme interventions and mathematical disease modelling, and most of them represented well-established global health research organisations and educational institutions. Most of the organisations present originated from high-income countries (HIC), such as the USA (6 institutes) and the UK (14 organisations and educational institutions). Eight institutions were based in LMICs: Zimbabwe (n=3), Uganda (n=3), South Africa (n=1) and India (n=1) (further described in companion paper14). The workshop included expert presentations, plenary dialogues and breakout discussion groups. On the final day, a list of recommendations made during the discussions was examined and prioritised in five key areas: HSV-2 epidemiology, HSV-2 diagnostic, HSV-2/HIV interactions, HSV-2 control measures and HSV-2 mathematical modelling.
In the absence of periodic re-evaluation of research priorities, there is a risk that research conducted will fail to respond to actual health needs or promote effective allocation of resources.15 To our knowledge, no review has been published to examine the progress made towards the research priorities defined in the 2001 WHO workshop.
This review aims to assess progress in addressing research priorities in two of the five areas, namely: HSV-2 epidemiology and HSV-2 diagnostics. The remaining three research priorities (HSV-2/HIV interactions, HSV-2 control measures and HSV-2 mathematical modelling) are addressed in a companion paper.16
Table 1 summarises subthemes identified in the 2001 WHO workshop in the two areas that are the subject of the current review.