Estimation of the Number of Injecting Drug Users Attending an Outreach Syringe-Exchange Program and Infection With Human Immunodeficiency Virus (HIV) and Hepatitis C Virus: the AjUDE-Brasil Project

Abstract

This study estimated the number of street injecting drug user (IDU) clients of a syringe-exchange program (SEP) who were infected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV). A two-sample capture-recapture method was carried out. The first capture listed all interviewed IDUs outreached for syringe exchange from April 1 to May 1, 1998; the second capture involved those outreached from May 2 to June 6, 1998. Blood spots were collected for HIV and HCV serologies. Analysis used captured probability model varying with time. We interviewed 55 IDUs in the first capture and 99 in the second; 17 participated in both samples. An estimate of 317 IDUs attending the SEP was obtained (95% confidence interval [CI] 235-467). Based on the overall seroprevalence rates for HIV (47.7%) and HCV (53.1%), it was estimated that 151 IDUs were HIV infected (95% CI 112-223) and 168 (95% CI 125-248) were HCV infected. Enumeration of IDUs associated with estimates of the total number of HIV and HCV seropositives provide a powerful tool for SEPs to help monitor the number of IDUs, to plan for provisions, and to organize the new demands on existing health facilities for HIV and HCV care.

Estudo de comportamento associado à infecção pelo HIV e HCV em detentas de um presídio de São Paulo, Brasil

“…Outros estudos internacionais observaram altas prevalên-cias como de 57,5% na prisão Australiana 23 Todos os estudos apresentados observaram associação da infecção do HCV com o uso de drogas. Embora, como destacamos acima, o risco da infecção pelo vírus da hepatite C esteja associado ao uso de drogas 4,8,14,21,22,23,24,25 , principalmente em seu uso parenteral, isto é, uso de droga injetá-vel, outra forma de transmissão que aparece cada vez mais consistente é a que se liga a aspectos do comportamento sexual, como a parceria com UDI.…”

Is human immunodeficiency virus/acquired immunodeficiency syndrome decreasing among Brazilian injection drug users? Recent findings and how to interpret them

“…3, the proportion of cases among IDUs in Rio de Janeiro (compared to all AIDS cases reported in each setting) has been fairly modest, compared to São Paulo and especially to the southernmost states, e.g. some municipalities from Santa Catarina, where AIDS cases reported among IDUs roughly corresponded to 50% of all AIDS cases reported in 1994 (Caiaffa et al 2003b). After 1997, the proportion of AIDS cases in IDUs from Rio de Janeiro has been further declining, corresponding to less than 4% of all AIDS cases in recent years.…”

“…Unlike Porto Alegre (RS) (Caiaffa et al 2003b), no study aiming to estimate the number of injection drug users has been carried out in Rio de Janeiro so far. Our own strenuous, 2 years-long, efforts to recruit in the last survey 609 injectors, exploring the most different settings with a team of community outreach workers, as well as former studies carried out in Rio de Janeiro drug treatment centers , suggest that the population of IDUs from Rio de Janeiro is relatively small and pales in comparison with the large population of IDUs from Brazil's southernmost states (Bastos et al 2002).…”

A capture-recapture technique to estimate the size of the injecting drug user population attending syringe exchange programs: AjUDE-Brasil II Project

“…Caiaffa et al 11 present an interesting discussion on the assumption of closed populations in this kind of study. Briefly, open population models cannot be applied with only two capture occasions.…”

“…A good example relates to surveys of hard-to-reach populations. The AjUDEBrasil I Project assessed injection drug users (IDUs) in five syringe exchange programs (SEPs) in Brazil 10,11 . The city of Porto Alegre in southern Brazil was used as the pilot for the capture-recapture methodology to estimate the size of the IDUs population attending the local SEP.…”