LB2.2 - Does screening for Neisseria gonorrhoeae and Chlamydia trachomatis affect the incidence of these infections in MSM taking HIV-PrEP? Results from a randomized, multicenter, controlled trial

Background

International guidelines recommend 3-site 3-monthly screening (3X3 screening) for Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) in men who have sex with men (MSM) taking HIV pre-exposure prophylaxis (PrEP). However, evidence supporting such practice is scarce. Here we present the results of the first randomized controlled trial comparing the effect of screening for NG/CT versus non-screening on the incidence of these infections in MSM taking PrEP.

Methods

Multicenter, randomized, controlled trial of 3X3 screening for NG/CT versus non-screening among MSM taking PrEP in 5 PrEP clinics in Belgium. Subjects were randomized (1:1) into the non-screening/3X3 screening arms. Participants attended 3-monthly visits at the PrEP clinic for a duration of 12 months. NG/CT was tested at each visit in both arms, but results were only provided to the non-screening arm when symptoms were present. The primary outcome was the incidence of NG/CT infections in each arm. Secondary outcomes included the incidence of NG and CT separately, the incidence of symptomatic infections and antibiotic consumption.

Results

Between September 2020 and June 2021, 508 and 506 subjects were randomized to the 3X3 screening and non-screening arms, respectively. The overall incidence rate (IR) of NG/CT was significantly higher in the non-screening arm (IR ratio (IRR) =1.318, 95%CI 1.068-1.627, p-value=0.01). Participants in the non-screening arm had a higher incidence of CT infections (IRR=1.435, 95%CI 1.098-1.875, p-value=0.008) and symptomatic CT infections (IRR=1.798; 95%CI 1.038-3.117, p-value=0.037). There was no significant difference in NG infections (IRR=1.162, 95%CI 0.757-1.783, p-value=0.138) or symptomatic NG infections (IRR=1.162, 95%CI 0.757-1.783, p-value=0.492). Participants in the non-screening arm consumed significantly less azithromycin (RR=0.788, 95%CI 0.719-0.863, p-value< 0.01), ceftriaxone (RR=0.561, 95%CI 0.426-0.739, p-value< 0.01) and doxycycline (RR=0.55, 95%CI 0.515-0.588, p-value< 0.01).

Conclusion

We did not show that non-screening for NG/CT is non-inferior to 3-site, 3-monthly screening in MSM taking PrEP in Belgium. The higher incidence in the non-screening arm was driven by CT infections and no difference in NG infections was found. Screening was associated with higher antibiotic consumption. Our findings do not provide strong evidence in favor of screening for NG/CT in MSM on PrEP. More RCTs are needed to further assess the benefits and risks of screening.