Risk of HIV Transmission During Combined ART Initiation for HIV-infected Persons with Severe Immunosuppression.

BACKGROUND:Individuals presenting for care with severe immunosuppression typically have high plasma HIV viral load (pVL) and may transmit HIV before and after initiation of combination antiretroviral therapies (cART).PATIENTS AND METHODS:Using risk equations and data collected in the IMEA 040 DATA trial on sexual behaviour and pVL level of 84 HIV-infected patients (23 women), we estimated monthly rates of HIV transmission for each virologically unsuppressed participant (pVL >50 copies/mL) who reported sex with HIV-negative or unknown serostatus (HNUS) partners at cART initiation, 24 weeks (W24) and W48 after; rates were considered negligible for other participants.RESULTS:At cART initiation, median pVL was 5.4 log10 copies/mL. The percentage of virologically unsuppressed patients decreased, from 100% at cART initiation to 27% (95% CI 16%-43%) for heterosexuals and 8% (95% CI 2%-22%) for MSM at W48 (P < 0.001). The percentage of patients reporting sex with HNUS partners increased between cART initiation and W48, from 23% (95% CI 10%-42%) to 42% (95% CI 25%-61%) for heterosexuals (P = 0.042) and from 41% (95% CI 21%-64%) to 73% (95% CI 52%-88%) for MSM (P = 0.004). Median monthly HIV transmission rates were 0.0540 (IQR 0.0339-0.0742) for MSM and 0.0018 (IQR 0.0014-0.0191) for heterosexuals at cART initiation, and were reduced by 95% (95% CI 87%-100%) for heterosexuals and 98% (95% CI 95%-100%) for MSM as early as W24.CONCLUSIONS:Risk of onward transmission for severely immunosuppressed individuals is high before and within the first weeks of cART, and persists, at a substantially reduced level, beyond 24 weeks of cART for some individuals. Earlier cART and protecting HIV-negative partners until full viral suppression is achieved could reduce HIV transmission.