TUESDAY, Feb. 15 (HealthDay News) -- The incidence of HIV infection among injection drug users (IDUs) declined from 1988 to 2008, while infection with hepatitis C virus (HCV) has decreased but is still significant, according to a study published online Jan. 31 in The Journal of Infectious Diseases.
Shruti H. Mehta, Ph.D., M.P.H., of the Johns Hopkins Bloomberg School of Public Health in Baltimore, and colleagues observed the trends of HIV and HCV incidence in IDUs during four time periods over a 20-year span (1988 to 1989, 1994 to 1995, 1998, and 2005 to 2008). Disease incidence was calculated within the first year of follow-up for the 2,061 IDUs who tested negative for HIV, and 373 IDUs who tested negative for HCV at baseline.
The researchers found a dramatic reduction in the incidence of HIV infection, from 5.5 cases per 100 person-years in the 1988 to 1989 group to zero cases in the 1998 and 2005 to 2008 groups. Although there were also reductions in HCV infection incidence, they were not significant. For IDUs younger than age 39, HCV infection prevalence declined in all time periods compared to the 1988 to 1989 cohort; while for IDUs aged 39 years or older, only the 2005 to 2008 cohort showed a decrease in HCV prevalence.
"HCV infection prevalence and incidence remain up to 10-fold higher than those of HIV infection in this population, reinforcing not only the continued need for preventive measures but also the need to expand care and treatment to those already infected," the authors write.