Higher viral loads and other risk factors associated with HIV-1 seroconversion during a period of high incidence among injection drug users in Bangkok.
We analyzed data from a prospective cohort study of injection drug users (IDUs) attending methadone treatment clinics in Bangkok, Thailand, during 1995-1998 to characterize factors associated with a period of high incidence (PHI) from July 1996 through January 1997 compared with periods of lower incidence. Sociobehavioral characteristics were similar for all participants during and outside the PHI except for the following: there was more reported drug injection while IDUs were incarcerated during the PHI (odds ratio, 1.67; p =.02) and significantly higher proportions of persons reported heroin injection (91% vs. 75%, respectively; p =.02) and higher frequencies of daily injection and sharing of injection equipment (40% vs. 25%, respectively; p =.05) during the PHI than outside the PHI. Through most of the first year after seroconversion, plasma HIV-1 loads were significantly higher in persons who seroconverted during the PHI than in those who seroconverted outside the PHI. Higher viral loads may potentially contribute to faster disease progression and increased infectiousness or transmissibility to subsequent contacts. Our findings suggest that prevention efforts to reduce the effective size and turnover within IDU sharing networks may have a significant impact on the epidemic by disrupting the rapid transmission of HIV-1 from recently infected, highly infectious individuals.
Hu
Dale J
DJ
HIV Vaccine Section Epidemiology Branch/DHAP, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. djh9@cdc.gov
Subbarao
Shambavi
S
Vanichseni
Suphak
S
Mock
Philip A
PA
van Griensven
Frits
F
Nelson
Robert
R
Nguyen
Lily
L
Kitayaporn
Dwip
D
Young
Nancy L
NL
Des Jarlais
Don
D
Byers
Robert
R
Choopanya
Kachit
K
Mastro
Timothy D
TD
D000328:Adult; D015331:Cohort Studies; D015483:HIV Antibodies / Q000097:blood*; D015658:HIV Infections / Q000175:diagnosis / Q000453:epidemiology / Q000276:immunology / Q000821:virology*; D006679:HIV Seropositivity; D015497:HIV-1 / Q000276:immunology / Q000502:physiology*; D006801:Humans; D015994:Incidence; D008297:Male; D011446:Prospective Studies; D012307:Risk Factors; D015819:Substance Abuse, Intravenous / Q000150:complications*; D013785:Thailand; D019562:Viral Load
D015483:HIV Antibodies