Risk of high-level viraemia in HIV-infected patients on successful antiretroviral treatment for more than 6 months.
OBJECTIVE
According to the Swiss Federal Commission for HIV/AIDS, HIV-infected patients on successful antiretroviral treatment have a negligible risk of transmitting HIV sexually. We estimated the risk that patients considered to have an undetectable viral load (VL) are actually viraemic.


METHODS
A Danish, population-based nationwide cohort study of HIV-infected patients with VL <51 HIV-1 RNA copies/mL for more than 6 months was carried out for the study period 2000-2008. The observation time was calculated from 6 months after the first VL <51 copies/mL to the last measurement of VL or the first VL >50 copies/mL. The time at risk of transmitting HIV sexually was calculated as 50% of the time from the last VL <51 copies/mL to the subsequent VL if it was >1000 copies/mL. The outcome was the time at risk of transmitting HIV sexually divided by the observation time.


RESULTS
We identified 2680 study subjects contributing 9347.7 years of observation time and 56.4 years of risk of transmitting HIV (VL>1000 copies/mL). In 0.6% [95% confidence interval (CI) 0.5-0.8%] of the overall observation time the patients had VL >1000 copies/mL. In the first 6 months this risk was substantially higher (7.9%; 95% CI 4.5-11.0%), but thereafter decreased and was almost negligible after 5 years (0.03%; 95% CI 0.0-0.2%). The risk was higher in injecting drug users, but otherwise did not differ between subgroups of patients.


CONCLUSIONS
The risk of viraemia and therefore the risk of transmitting HIV sexually are high in the first 12 months of successful antiretroviral treatment, but thereafter are low.
Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Denmark. fren74@gmail.com
F N
FN
Engsig
L H
LH
Omland
M V
MV
Larsen
L D
LD
Rasmussen
T
T
Qvist
J
J
Gerstoft
N
N
Obel
D000293:Adolescent; D000328:Adult; D044966:Anti-Retroviral Agents / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D015658:HIV Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000635:transmission; D006801:Humans; D008297:Male; D055118:Medication Adherence; D011159:Population Surveillance; D018570:Risk Assessment / Q000379:methods; D012725:Sexual Behavior / Q000706:statistics & numerical data; D015819:Substance Abuse, Intravenous / Q000150:complications; D013997:Time Factors; D017211:Treatment Failure; D019562:Viral Load / Q000187:drug effects; D014766:Viremia / Q000188:drug therapy / Q000453:epidemiology*
D044966:Anti-Retroviral Agents