Antibody levels predict vaccine efficacy: Symptomatic COVID-19 infection can be prevented by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines. A “correlate of protection” is a molecular biomarker to measure how much immunity is needed to fight infection and is key for successful global immunization programs. Gilbert et al . determined that antibodies are the correlate of protection in vaccinated individuals enrolled in the Moderna COVE phase 3 clinical trial (see the Perspective by Openshaw). By measuring binding and neutralizing antibodies against the viral spike protein, the authors found that the levels of both antibodies correlated with the degree of vaccine efficacy. The higher the antibody level, the greater the protection afforded by the messenger RNA (mRNA) vaccine. Antibody levels that predict mRNA vaccine efficacy can therefore be used to guide vaccine regimen modifications and support regulatory approvals for a broader spectrum of the population. —PNK

Twice-yearly subcutaneous lenacapavir has been shown to be efficacious for prevention of HIV infection in cisgender women. The efficacy of lenacapavir for preexposure prophylaxis (PrEP) in cisgender men, transgender women, transgender men, and gender-nonbinary persons is unclear. In this phase 3, double-blind, randomized, active-controlled trial, we randomly assigned participants in a 2:1 ratio to receive subcutaneous lenacapavir every 26 weeks or daily oral emtricitabine-tenofovir disoproxil fumarate (F/TDF). The primary efficacy analysis compared the incidence of HIV infection in the lenacapavir group with the background HIV incidence in the screened population. The secondary efficacy analysis compared the incidence of HIV infection in the lenacapavir group with that in the F/TDF group. Among 3265 participants who were included in the modified intention-to-treat analysis, HIV infections occurred in 2 participants in the lenacapavir group (0.10 per 100 person-years; 95% confidence interval [CI], 0.01 to 0.37) and in 9 participants in the F/TDF group (0.93 per 100 person-years; 95% CI, 0.43 to 1.77). The background HIV incidence in the screened population (4634 participants) was 2.37 per 100 person-years (95% CI, 1.65 to 3.42). The incidence of HIV infection in the lenacapavir group was significantly lower than both the background incidence (incidence rate ratio, 0.04; 95% CI, 0.01 to 0.18; P<0.001) and the incidence in the F/TDF group (incidence rate ratio, 0.11; 95% CI, 0.02 to 0.51; P = 0.002). No safety concerns were identified. A total of 26 of 2183 participants (1.2%) in the lenacapavir group and 3 of 1088 (0.3%) in the F/TDF group discontinued the trial regimen because of injection-site reactions. The HIV incidence with twice-yearly lenacapavir was significantly lower than the background incidence and the incidence with F/TDF. (Funded by Gilead Sciences; PURPOSE 2 ClinicalTrials.gov number, NCT04925752.).

Reductions in human immunodeficiency virus (HIV) incidence with pre-exposure prophylaxis (PrEP) for men who have sex with men (MSM) will require significant coverage of those at risk. We propose a simplified framework, similar to the HIV care continuum, to achieve protection with PrEP as follows: 1. At-risk MSM; 2. Awareness of and willingness to take PrEP; 3. Access to healthcare; 4. Receiving a prescription; and 5. Adhering to effective PrEP. We evaluated the PrEP care continuum on an Atlanta cohort of MSM and projected how many MSM might achieve protection from HIV. Even with optimistic estimates, few Atlanta MSM (15%) are projected to achieve protection from HIV with PrEP given the significant barriers described. Each continuum step represents an important point for intervention that could substantially increase the overall effectiveness of PrEP. In addition, novel strategies for PrEP delivery are needed to achieve the necessary effectiveness for Atlanta MSM at risk of HIV.

Background: HIV incidence among US young, black men who have sex with men (YBMSM) is high, and structural barriers (eg lack of health insurance) may limit access to Pre-exposure prophylaxis (PrEP). Research studies conducted with YBMSM must ensure access to the best available HIV prevention methods, including PrEP. Methods: We implemented an optional, nonincentivized PrEP program in addition to the standard HIV prevention services in a prospective, observational cohort of HIV-negative YBMSM in Atlanta, GA. Provider visits and laboratory costs were covered; participant insurance plans and/or the manufacturer assistance program were used to obtain drugs. Factors associated with PrEP initiation were assessed with prevalence ratios and time to PrEP initiation with Kaplan–Meier methods. Results: Of 192 enrolled YBMSM, 4% were taking PrEP at study entry. Of 184 eligible men, 63% indicated interest in initiating PrEP, 10% reported no PrEP interest, and 27% wanted to discuss PrEP again at a future study visit. Of 116 interested men, 46% have not attended a PrEP initiation appointment. Sixty-three men (63/184; 34%) initiated PrEP; 11/63 (17%) subsequently discontinued PrEP. The only factor associated with PrEP initiation was reported sexually transmitted infection in the previous year (prevalence ratio 1.50, 95% confidence interval: 1.002 to 2.25). Among interested men, median time to PrEP initiation was 16 weeks (95% confidence interval: 7 to 36). Conclusions: Despite high levels of interest, PrEP uptake may be suboptimal among YBMSM in our cohort even with amelioration of structural barriers that can limit use. PrEP implementation as the standard of HIV prevention care in observational studies is feasible; however, further research is needed to optimize uptake for YBMSM.

Recruiting valid samples of men who have sex with men (MSM) is a key component of the US human immunodeficiency virus (HIV) surveillance and of research studies seeking to improve HIV prevention for MSM. Social media, such as Facebook, may present an opportunity to reach broad samples of MSM, but the extent to which those samples are comparable with men recruited from venue-based, time-space sampling (VBTS) is unknown. The objective of this study was to assess the comparability of MSM recruited via VBTS and Facebook. HIV-negative and HIV-positive black and white MSM were recruited from June 2010 to December 2012 using VBTS and Facebook in Atlanta, GA. We compared the self-reported venue attendance, demographic characteristics, sexual and risk behaviors, history of HIV-testing, and HIV and sexually transmitted infection (STI) prevalence between Facebook- and VTBS-recruited MSM overall and by race. Multivariate logistic and negative binomial models estimated age/race adjusted ratios. The Kaplan-Meier method was used to assess 24-month retention. We recruited 803 MSM, of whom 110 (34/110, 30.9% black MSM, 76/110, 69.1% white MSM) were recruited via Facebook and 693 (420/693, 60.6% black MSM, 273/693, 39.4% white MSM) were recruited through VTBS. Facebook recruits had high rates of venue attendance in the previous month (26/34, 77% among black and 71/76, 93% among white MSM; between-race P=.01). MSM recruited on Facebook were generally older, with significant age differences among black MSM (P=.02), but not white MSM (P=.14). In adjusted multivariate models, VBTS-recruited MSM had fewer total partners (risk ratio [RR]=0.78, 95% CI 0.64-0.95; P=.01) and unprotected anal intercourse (UAI) partners (RR=0.54, 95% CI 0.40-0.72; P<.001) in the previous 12 months. No significant differences were observed in HIV testing or HIV/STI prevalence. Retention to the 24-month visit varied from 81% for black and 70% for white MSM recruited via Facebook, to 77% for black and 78% for white MSM recruited at venues. There was no statistically significant differences in retention between the four groups (log-rank P=.64). VBTS and Facebook recruitment methods yielded similar samples of MSM in terms of HIV-testing patterns, and prevalence of HIV/STI, with no differences in study retention. Most Facebook-recruited men also attended venues where VTBS recruitment was conducted. Surveillance and research studies may recruit via Facebook with little evidence of bias, relative to VBTS.