Repeat HIV Testing and Risky Sexual Behavior: Evidence from a Randomized Controlled Trial in Malawi

Malawi has one of the highest HIV prevalence rates in the world with 10% of the adult population infected. As in many countries in sub-Saharan Africa, heterosexual intercourse is the predominant mode of HIV transmission in Malawi, accounting for 88% of all new infections. Moreover, several studies have shown that a significant proportion of couples in steady relationships have serodiscordant status. Therefore, finding ways of reducing HIV transmission among serodiscordant couples is critical for controlling the epidemic. 

There has been a recent shift towards couples HIV testing and counseling (HTC) as a means for preventing within couple HIV transmission. Although prior work encouragingly shows that couples HTC can be successful in terms of reducing risky sexual behavior, there is evidence that such reductions are not sustained over time. This suggests that a longer duration after a couple’s HTC session may be associated with greater expectation that seroconversion occurred, reducing the perceived value of condom use. There is little incentive to use condoms if both partners believe they are positive. Therefore, reducing the duration between HTC sessions by increasing the frequency of HTC may prolong safe sexual behavior, and reduce the probability of seroconversion.

In this study, we enrolled 337 serodiscordant couples in Zomba district, Malawi. We then randomly assigned 170 couples to receive HTC every 4 months and 167 couples to be in a control group (HTC only at enrollment).  We conducted a baseline survey and HIV test at enrollment and a follow-up survey and HIV test after 12 months. We measured the effect of the intervention on seroconversion, condom use, and subjective expectations of seroconversion.

We found that there was slightly more seroconversion in the treatment group (5.2%) compared to the control group (2.3%), the opposite of what we expected, although differences were not statistically significant (95% CI  2.0%, 7.9%). Couples that received repeat HTC were less likely to report risky sexual behavior at follow-up—19 percentage points less likely to report usually having sex without a condom (95% CI 5%, 33%) and 13 percentage points more likely to report usually having sex with a condom (95% CI 5%, 21%) (we found similar patterns for other measures of condom use).   We found no difference in subjective expectations of seroconversion.

Overall our findings are mixed. One the one hand, couples that received repeated HTC reported substantially greater condom use, a result that was robust to a variety of estimation methods. However, there was no difference in couple’s perceived likelihood that seroconversion had occurred at follow-up, which is what we expected to be the pathway to reducing risky behavior. More importantly, there was no evidence that repeat testing reduced seroconversion. Therefore, our findings that repeat HTC reduced risky sexual behavior should be interpreted with caution.