High HIV incidence in a cohort of male injection drug users in Delhi, India.
BACKGROUND
India has an estimated 177,000 injection drug users (IDU) with a national HIV prevalence of 7.14%. Reliable estimates of HIV incidence are not available for this population.


METHODS
We report HIV incidence in a cohort of male, HIV-negative IDUs recruited through peer-referral, targeted outreach and as walk-in clients in Delhi from May to October, 2011. Fourth-generation Antigen-Antibody tests were used to diagnose new infections and results were confirmed using Western blot tests. HIV incidence based on HIV seroconversion was calculated as number of events/person-years. Cox regression was used to identify significant (p<0.05) seroconversion predictors.


RESULTS
A total of 2790 male HIV-negative IDUs were recruited at baseline; 67.4% (n=1880) returned for their first follow-up visit and 96% (n=1806) underwent HIV testing. Participants were followed for a median of 9.7 months. A total of 112 new HIV infections occurred over a cumulative 1398.5 person-years of follow-up resulting in an incidence rate of 8.01 new infections/100 person-years (95% CI: 6.65-9.64); 74% of these participants reported risky injection practices in the past month. In multivariate analysis, moderate-high risk injection behaviors (Adjusted Hazard Ratio [AHR] 2.59; 95% CI 1.45-4.62) were associated with a higher risk of new infections.


CONCLUSIONS
Male IDUs in Delhi continue to practice unsafe injection practices leading to high sero-incidence despite the availability of HIV prevention services offered through targeted intervention programs.
Population Council, Zone 5A, India Habitat Center, Lodhi Road, New Delhi 110003, India. Electronic address: asarna@popcouncil.org.
Avina
A
Sarna
Population Council, Zone 5A, India Habitat Center, Lodhi Road, New Delhi 110003, India.
Lopamudra Ray
LR
Saraswati
Population Council, Zone 5A, India Habitat Center, Lodhi Road, New Delhi 110003, India.
Mary
M
Sebastian
Population Council, Zone 5A, India Habitat Center, Lodhi Road, New Delhi 110003, India.
Vartika
V
Sharma
Sahara Center for Residential Care and Rehabilitation, B-9/11 Chandan Singh Market, IGNOU Road, Siadulajab, New Delhi 110030, India.
Ira
I
Madan
Sahara Center for Residential Care and Rehabilitation, B-9/11 Chandan Singh Market, IGNOU Road, Siadulajab, New Delhi 110030, India.
Dean
D
Lewis
ARISE Project, PATH, 1800K Street NW, 8th Floor, Washington, DC 20006, USA; Population Council, 4301 Connecticut Ave NW, Suite 280, Washington, DC 20008, USA.
Julie
J
Pulerwitz
ARISE Project, PATH, 1800K Street NW, 8th Floor, Washington, DC 20006, USA.
Ibou
I
Thior
Population Council, 4301 Connecticut Ave NW, Suite 280, Washington, DC 20008, USA.
Waimar
W
Tun
D000328:Adult; D015658:HIV Infections / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D015994:Incidence; D007194:India / Q000453:epidemiology; D008297:Male; D015995:Prevalence; D016016:Proportional Hazards Models; D012307:Risk Factors; D015819:Substance Abuse, Intravenous / Q000150:complications* / Q000453:epidemiology; D055815:Young Adult
Cohort study; HIV-incidence; India; Injection drug user; Sexual behavior; Unsafe injection practices