Risk of HIV transmission among HIV-serodiscordant sex partners when antiretroviral therapy (with or without viral load suppression), condoms or both were used
| Question | Evidence | Absolute risk estimate | Quality of evidence | Risk assessment |
|---|---|---|---|---|
| No. of HIV transmissions/person-years | No. of HIV transmissions per 100 person-years (95% CI) | |||
| 1. ART* | Het: 23/9922 MSM: 0/588.96 WSW: no direct evidence Overall: 23/10 511 | Het/WSW: 0.23 (0.15–0.35) MSM: 0.00 (0.00–0.63) Overall: 0.22 (0.14–0.33) | Het: high MSM: moderate owing to serious indirectness‡ and imprecision§ WSW: moderate owing to very serious indirectness¶ | Low risk of transmission (potential for transmission; few reports of transmission) |
| 2. ART + viral suppression† | Het: 0/799 MSM: 0/527.59 WSW: no direct evidence Overall: 0/1327 | Het/WSW: 0.00 (0.00–0.46) MSM: 0.00 (0.00–0.70) Overall: 0.00 (0.00–0.28) | Het/MSM: high WSW: moderate owing to serious indirectness** and imprecision§ | Negligible risk of transmission (potential for transmission; no confirmed transmission) |
| 3. ART* + condom | Not available | 0.003 (0.00–0.03) to 0.11 (0.02–0.73) per 1000 acts (depending on population and sex acts in question) | Modelled estimate from Patel et al., 20148 | Low risk of transmission for penile–vaginal and penile–anal sex (potential for transmission; few reports of transmission) |
| 4. ART + viral suppression† + condom | No direct evidence Indirect evidence from Q2 was used. | Het: 0.00 (0.00–0.46) MSM: 0.00 (0.00–0.70) Overall: 0.00 (0.00–0.28) | Het/MSM: moderate owing to serious indirectness†† and imprecision§ | Negligible risk of transmission (potential for transmission; no confirmed transmission) |
| 5. Condom | Het: 11/946.3 | 1.14 (0.56–2.04) | Stable and conclusive evidence from a Cochrane review7 | Low risk of transmission (potential for transmission; few reports of transmission) |
Note: ART = antiretroviral therapy, CI = confidence interval, Het = heterosexual couples, MSM = men who have sex with men, Q2 = to determine risk when a sex partner who is HIV-positive is taking antiretroviral therapy and has a suppressed viral load, WSW = women who have sex with women.
↵* Viral load levels were variable.
↵† Viral load < 200 copies/mL as per data in the included studies.
↵‡ Indirectness was rated serious because almost all follow-up in both studies occurred under conditions of viral load suppression; therefore, the population does not fully reflect a population of individuals on ART with varying levels of viral load.
↵§ Imprecision was rated serious because we considered the sample size and follow-up time to be insufficient (i.e., < 2000 participants and < 4000 person-years).
↵¶ Indirectness was rated very serious because the studies did not account consistently for relevant confounding variables (e.g., condom use, type of sex act, frequency of sex act, sexually transmitted infections, injection drug use, duration on ART and viral load), and the estimates were from a different population (i.e., heterosexual sex partners).
↵** Indirectness was rated serious because the estimates were from a different population (i.e., heterosexual sex partners).
↵†† Indirectness was rated serious because the exposure does not directly match the question as studies contributing to this estimate included couples performing sex acts without condom use.