Geographical and demographic clustering of gonorrhoea in London
- Claire L Risley1,
- Helen Ward1,
- Bhudipa Choudhury1,
- Cynthia J Bishop1,
- Kevin A Fenton3,
- Brian G Spratt1,
- Catherine A Ison4,
- Azra C Ghani2
- 1Department of Infectious Disease Epidemiology, Imperial College London, St Mary’s Hospital, London, UK
- 2Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK
- 3Division of Sexually Transmitted Disease Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
- 4Sexually Transmitted Bacteria Reference Laboratory, Health Protection Agency Centre for Infections, Health Protection Agency, London, UK
- Correspondence to: Azra Ghani Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK; azra.ghani{at}lshtm.ac.uk
- Accepted 15 June 2007
- Published Online First 16 August 2007
Abstract
Background: Gonorrhoea is an important cause of sexual ill health and is concentrated in geographical areas and demographic groups. This study explores the distribution of gonorrhoea across London.
Methods: Epidemiological data on all gonorrhoea cases were collected from 13 major genitourinary clinics in London between 1 June and 30 November 2004. Samples were stored centrally and typed using NG-MAST. The postcode of each case’s main residence was used to calculate incidence of gonorrhoea by borough using data from the UK 2001 census and a population survey on residence of men who have sex with men (MSM).
Results: 2891 cases were confirmed, 1822 of which had postcode data, resided in London, and had their strain successfully typed. There was a very high incidence of gonorrhoea in MSM (1834 per 100 000 population) and heterosexuals of black ethnicity (392 per 100 000). The incidence among heterosexuals was highest in City of London (390 per 100 000, 95% CI 213 to 566), Southwark (308 per 100 000, 95% CI 280 to 336), Hackney (284 per 100 000, 95% CI 254 to 313), and Lambeth (216 per 100 000, 95% CI 194 to 239) and was not associated with measures of social deprivation (correlation coefficient = 0.0008, p = 0.97) but was strongly associated with black ethnicity (correlation coefficient = 0.48, p = 0.01). 45% of cases had one of the 21 major strains; eight of these strains were significantly clustered geographically and persisted for a shorter duration than those that were not clustered. Patients travelled a mean of 7.7 km from their home to the clinic.
Conclusions: High gonorrhoea incidence in London is observed in MSM and heterosexuals of black ethnicity. Endemic strains in both MSM and heterosexuals are diagnosed at multiple clinics. Interventions, including partner notification, must therefore operate between clinics.
- GC, gonorrhoea
- GRASP, Gonococcal Resistance to Antimicrobials Surveillance Programme
- MSM, men who have sex with men
- STIs, sexually transmitted infections
Footnotes
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Funding: This work was funded by the Wellcome Trust (GR072422). The funder played no part in the design or execution of the study.
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Conflict of interest: HW is co-editor and CI is an associate editor of the journal Sexually Transmitted Infections.
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Ethical approval: The study data were collected as part of the Gonococcal Resistance to Antimicrobials Surveillance Programme (GRASP) coordinated by the Health Protection Agency for which Multicentre (MREC) and local (LREC) approval was obtained.
Contributors: CAI, KAF, HW, ACG, and BGS designed the study; BC and CJB carried out the experimental work; CLR and ACG undertook the statistical analysis; and all authors contributed to the writing of the report.
