HIV/Sexually Transmitted Infections (STIs)
28 March 2013
From 1 April 2013, the HPA becomes part of Public Health England which, through its local Centres, with support from national services as required, will work with local authorities and other organisations to control outbreaks of sexually transmitted infections. The following review of recent STI outbreaks covers four main infections of concern -syphilis, gonorrhoea, Lymphogranuloma venereum (LGV) and shigellosis - notes the lessons learned from past outbreaks and provides advice on effective outbreak management for local authorities, service providers and other stakeholders.
Over the last 10 years there has been a steady rise in new diagnoses of STIs. While much of this rise is associated with the expansion of testing and screening (such as through the National Chlamydia Screening Programme), and improvements in diagnostic test sensitivity, it is clear that ongoing unsafe sexual behaviour is contributing to high rates of STI transmission. Of particular concern is the recent emergence of outbreaks of less common STIs - gonorrhoea, infectious syphilis (primary, secondary and early latent) and Lymphogranuloma venereum (LGV), together with shigellosis, which can be sexually transmissible - among young heterosexuals and men who have sex with men (MSM).
Young heterosexuals: syphilis and gonorrhoea
Infectious syphilis has re-established itself within the UK and other industrialized countries over the past 15 years. In 2011, in England, 67% of the 2820 cases for which sexual orientation data were available were seen in MSM. However, a small but increasing number of cases are being seen in young heterosexuals and adolescents. Outbreaks with involvement of adolescents aged less than 19 years have been reported from across the UK (South East Hampshire, Teesside, Greater Manchester, central Scotland, and East Anglia) in recent years [1,2,3,4,5]. Those affected were often from deprived areas and reported a high turnover of sexual partners. Some of the outbreaks among adolescents and the socially vulnerable and have raised issues of child protection. A small number of cases of congenital syphilis were associated with these outbreaks, reflecting challenges to service access (for antenatal screening) in these socially marginalised populations .
The number of gonorrhoea diagnoses has also been rising in the last few years and, in 2011, about 21,000 gonorrhoea infections were diagnosed in England. Highest rates of infection are seen among young adults, with more than half of all cases reported among heterosexuals aged 15 to 24 years. High rates of infection are also seen in black ethnic minorities, especially black Caribbean populations, in areas of high deprivation, and in MSM. Large outbreaks of gonorrhoea among young heterosexuals are currently being investigated in the North East and in Merseyside. The outbreak in the North East (Northumberland) has been ongoing for over a year. Ninety-six cases were seen in 2012 and, as with the syphilis outbreaks, many of the cases are socially marginalised and/or from deprived backgrounds, reporting risky sexual behaviour including high numbers of sexual partners who are often difficult to trace. Consequently, the outbreak has proved difficult to control.
Men who have sex with men: syphilis, LGV and shigellosis
For the past decade, diagnoses of syphilis in England have been at their highest level since the 1950s. In 2011, 2915 cases of infectious syphilis were diagnosed at sexual health clinics in England; 90% of cases were in men. Most of the increase in men was seen in white MSM, aged 25-34 years, many of whom are co-infected with HIV. Unsafe sexual behaviour is likely to explain much of this rise. Syphilis is now considered to be endemic in MSM. However, sporadic outbreaks still occur among behaviourally bisexual men and in low prevalence areas.
LGV is a sexually transmitted infection caused by certain types of Chlamydia trachomatis. Although historically considered a heterosexually acquired infection of the tropics, outbreaks of LGV have been occurring in MSM in western industrialised countries since 2003. There have been large numbers of cases seen in the UK, predominantly London, Brighton and Manchester, and the general diagnostic profile is of HIV positive, white, MSM involved in dense sexual networks most of whom report unprotected anal intercourse. Of particular concern has been the rapid increase in cases, with half of all cases diagnosed since 2010. The UK response has been co-ordinated by a multi-disciplinary outbreak control team (OCT) led by HPA and following HPA and British Association for Sexual Health and HIV (BASHH) guidelines on STI outbreak management. Infection control has focussed on offering testing to HIV-positive MSM during routine clinical care and raising awareness so that those at risk can make informed decisions in their sexual relationships, be aware of the symptoms of infection, and attend clinical services for testing and treating when necessary. In 2010, the HPA launched an initiative whereby local Health Protection Units (HPUs) collaborated with Terrence Higgins Trust to encourage the display of health information and provide hygiene advice at 'sex on premises' venues . Leaflet campaigns and targeted press releases were also employed to raise awareness and promote condom use and LGV testing of HIV-positive MSM during routine clinical care . Nevertheless, although these interventions have probably attenuated the epidemic, infection persists in a relatively small core population and effective control will depend on continued and strengthened prevention activities targeting this population.
Shigellosis (bacillary dysentery) is a bacterial disease that invades the lining of the intestine, causing inflammation, ulcerations and diarrhoea. The most common route of transmission is from person to person as a result of poor hygiene. In England, most cases are associated with foreign travel although there are occasional reports of UK-acquired cases associated with sexual transmission, predominantly among MSM. In recent years, there have been national increases in UK-acquired S. flexneri and S. sonnei which have been associated with transmission among MSM . In 2012, the male to female sex ratio of the 89 diagnoses of S. flexneri 3a was 8:1. This, together with recent enhanced surveillance, indicates that the recent outbreak has primarily occurred among MSM. London has been the focus of the recent outbreaks of S. flexneri and S. sonnei among MSM but cases have also been reported from Manchester and the South East.
Response and control
Comprehensive guidance is available for the management of STI outbreaks . When an outbreak is identified, a local outbreak control team (OCT) should be formed with appropriate representation depending on the patterns of local transmission and likely public health impact. The OCT is usually convened by the local consultant in communicable disease control at the appropriate PHE Centre. These teams ensure locally relevant control measures are in place. A national OCT or incident group may be established where there is evidence that the outbreak is spreading beyond local and regional boundaries, as was the case for the recent shigellosis outbreak among MSM. For all outbreaks, control measures are likely to include expanded testing, treatment and appropriate patient notification (PN) exercises, as well as strategies for raising awareness in the local population and among health professionals. The promotion of safe sex, through leaflet campaigns and targeted press releases, is also often employed.
Even when such measures have been taken, control can be elusive. STI outbreaks can take months to develop as transmission is related to the density and structure of local sexual networks. PN is crucial to effective outbreak management but can be challenging where there are large numbers of untraceable sexual partnerships. This can result in a significant undiagnosed pool of infection and the potential for ongoing transmission within the wider sexually active population. In the recent heterosexual outbreaks, PN success rates were often poor and the outbreaks difficult to control. Where outbreaks were contained, effective PN almost certainly contributed to this. Service access by vulnerable groups may also be a problem, with many patients not registered with health services.
Specific and tailored interventions may be helpful in controlling outbreaks among MSM where a high turnover of untraceable sexual partners is common. For the LGV outbreak, an initiative was launched to identify social venues such as saunas and night clubs attended by patients diagnosed with LGV. HPUs collaborated with Terrence Higgins Trust to undertake site visits and encourage the display of health information (posters) and provide advice on hygiene. Local enhanced surveillance may also be helpful to inform further prevention activities.
Organising outbreak investigations under PHE
Effective sexual health (SH) networks require good clinical leadership to help manage OCTs, provide expertise and training and to ensure relevant guidelines (for example, local prescribing guidelines in response to increased levels of antimicrobial resistance) are implemented consistently across providers. Commissioners may also be required to commission additional services to support outbreak management and must ensure that experience from earlier outbreaks is built into future commissioning plans. For example, this might include targeted resources for work with high risk groups, improving access to antenatal screening. The BASHH PN standards should be included in contract specifications and monitored appropriately.
Improving sexual health, and controlling STI outbreaks in particular, requires the establishment of strong local SH networks that include all local providers and commissioners from across local authorities, PHE and Clinical Commissioning Groups (CCGs). Effective networks are necessary to ensure good working relationships across providers and to enable rapid communications about increased diagnoses that may indicate an outbreak. Service providers must report any concerns about increased STI cases to the local PHE Centre and local commissioners so that the significance of any increase can be determined.
1. Welfare W, Lacey H, Lighton L, Simms I. An outbreak of infectious syphilis among young heterosexuals in an English Town. International Journal of STD & AIDS 2011; 22: 519-20.
2. Abu-Rajab K, Wallace L. Heterosexual transmission of infectious syphilis in central Scotland, 2009. Int J STD AIDS 2011; 22: 517-18.
3. Acheson P, McGivern M, Frank P, et al. An ongoing outbreak of heterosexually-acquired syphilis across Teesside, UK. Int J STD AIDS 2011; 22: 514-16.
4. Morgan E, Blume A, Carroll R. A cluster of infectious syphilis among young heterosexuals in south-east Hampshire. Int J STD AIDS 2011; 22: 512-13.
5. Raouf M, Sundkvist T, Emmett L. Investigation of a cluster of syphilis among heterosexuals in an English town. Int J STD AIDS 2011; 22: 521-22
6. Simms I, Bell G, Hughes G. Int J STD AIDS 2011; 22: 481-482.
7. Epidemic of Lymphogranuloma venereum (LGV) in men who have sex with men in the UK intensifies. HPR 5 (24), 17 June 2011.
8. Substantial increase in cases of Lymphogranuloma venereum (LGV) in UK. HPR 4 (8), 26 February 2010.
9. Outbreak of UK acquired Shigella flexneri in men who have sex with men. HPR 5 (40), 7 October 2011.
10. Guidance for managing STI outbreaks and incidents. Available at: http://www.hpa.org.uk/webc/HPAwebFile/HPAweb_C/1214553002033.