Table 1:

Methods used to identify and study HIV outbreaks

	Surveillance of new PWID cases (to identify outbreak)	Estimate of PWID population	Changes in drug use patterns used by PWID	Contact tracing investigation	Increase in HIV testing for PWID	Cohort study to examine incidence and risk factors	Case control or cross-sectional study to examine risk factors and associations	Qualitative interviews with stakeholders	Phylogenic analysis on cases
Study location
Athens, Greece	Yes	Yes (n=1976)	No	No	Yes	Yes	Yes	Yes	Yes
Bucharest, Romania	Yes	Yes (n=l8500)	Yes	Yes	No	No	No	Yes	Yes
Dublin, Ireland	Yes	Yes (n=13480)	Yes	Yes	Yes	No	Yes	Yes	Yes
Tel Aviv, Israel	Yes	Yes (n=20000)*	Yes	Yes	Yes	Yes	No	Yes	Yes
Luxembourg	Yes	Yes (n=1500)	Yes	No	Yes	No	Yes	Yes	Yes
Scott County, IN, USA	Yes	Yes (n=500–600)	Yes	Yes	Yes	No	Yes	Yes	Yes
Glasgow, Scotland, UK	Yes	Yes (n=8862)	Yes	Yes	Yes	No	Yes	Yes	Yes
Southeastern Saskatchewan, Canada	Yes	No	Unknown	Yes	Yes	No	Yes	Yes	Yes
Summary of studies	8 of 8	7 of 8 (range 500–20 000) 500–20 000	6 out of 8	6 out of 8	7 out of 8	2 out of 8	6 out of 8	8 out of 8	8 out of 8

PWID=people who inject drugs.

^*Estimate is for country level population of PWID.