Background Since 2011, an outbreak of gonorrhoea (GC) has affected heterosexual young adults in Northumberland, England. Despite extensive control measures, the outbreak has continued. An in-depth epidemiological analysis, using enhanced clinical and behavioural data complemented by molecular typing, was used to characterise the sexual networks associated with the outbreak and thereby enable better targeting.
Methods A multifaceted approach to outbreak control has been implemented including health promotion/awareness-raising amongst public and healthcare professionals, increased testing including dual-testing of chlamydia screening programme samples, and the introduction of enhanced surveillance linked to molecular typing (NG-MAST) to identify clusters and delineate the extent of the outbreak.
Enhanced surveillance collected demographic, risk factor and partner information for the outbreak cases (Northumberland residents) and cases in the wider area from April 2011 to December 2012.
Results A total of 433 GC cases were diagnosed in the study period, of which 166 (38%) were part of the outbreak. Compared with other local cases, outbreak cases were significantly associated with; being heterosexual (OR:12.8[95% C.I.: 5–31]), female (OR:2.2[1–3]), white British (OR:9.6[2–84]), under 20 years (OR:3.3[2–5]), co-infected with Chlamydia (OR:1.8[1–3]), no contraception use (OR:2.7[1–6]), no test of cure (OR:1.6[1–2]) and strain type genogroup G25 (OR:11.6[3–55]).
G25 accounted for 58% of all typed cases (5% in UK) and was almost exclusively found in the outbreak area, which supported local knowledge that the networks were restricted to a particular geographical area and the outbreak was not spreading into the wider population. G2992 (4% in UK, 18% in local cases) was not seen amongst outbreak cases.
Conclusions Enhanced epidemiological data complemented by molecular typing can be used to better characterise outbreaks; this study demonstrated a highly concentrated sexual network of young adults, highlighting the importance of targeted messages and approaches to improve uptake of testing and practise of safe sex.
- Molecular typing