Sexual Exposures Associated With Mpox Infection: California, November 2022 to June 2023.

BACKGROUND: Exposures associated with mpox infection remain imperfectly understood. METHODS: We conducted a case-control study enrolling participants who received molecular tests for mpox/orthopoxvirus in California from November 2022 through June 2023. We collected data on behaviors during a 21-day risk period before symptom onset or testing among mpox case patients and test-negative controls. RESULTS: Thirteen of 54 case patients (24.1%) and 5 of 117 controls (4.3%) reported sexual exposure to individuals they identified as potential mpox case patients ("index contacts"; odds ratio [OR], 7.7 [95% confidence interval (CI), 2.5-19.3] relative to individuals who did not report exposure to potential mpox case patients). Among these participants, 10 of 13 case patients (76.9%) and 2 of 5 controls (40.0%) reported that their index contacts were not experiencing symptoms visible to participants during sex (OR, 14.9 [95% CI, 3.6-101.8]). Only 3 of 54 case patients (5.6%) reported exposure to symptomatic index contacts. Case patients reported more anal/vaginal sex partners than did controls (adjusted OR, 2.2 [95% CI, 1.0-4.8] for 2-3 partners and 3.8 [1.7-8.8] for ≥4 partners). Male case patients with penile lesions more commonly reported insertive anal/vaginal sex than those without penile lesions (adjusted OR, 9.3 [95% CI, 1.6-54.8]). Case patients with anorectal lesions more commonly reported receptive anal sex than those without anorectal lesions (adjusted OR, 14.4 [95% CI, 1.0-207.3]). CONCLUSIONS: Sexual exposure to contacts known or suspected to have experienced mpox was associated with increased risk of infection, often when index contacts lacked apparent symptoms. Exposure to more sex partners, including those whom participants did not identify as index contacts, was associated with increased risk of infection in a site-specific manner. While participants' assessment of symptoms in partners may be imperfect, these findings suggest that individuals without visibly prominent mpox symptoms transmit infection.

Reduced Odds of Mpox-Associated Hospitalization Among Persons Who Received JYNNEOS Vaccine - California, May 2022-May 2023.

The effectiveness of 1 dose of JYNNEOS vaccine (modified vaccinia Ankara vaccine, Bavarian Nordic) against hospitalization for mpox (caused by Monkeypox virus), has been demonstrated; however, the impact of 2 doses on hospitalization risk, especially among persons infected with HIV, who are at higher risk for severe disease, is an important factor in evaluating vaccine effectiveness against mpox disease severity and Monkeypox virus infection. Surveillance data collected by the California Department of Public Health were used to evaluate whether receipt of 2 doses of JYNNEOS vaccine reduced the odds of hospitalization among persons with mpox. The odds of hospitalization among persons with mpox who had received 1 or 2 JYNNEOS doses were 0.27 (95% CI = 0.08-0.65) and 0.20 (95% CI = 0.01-0.90), respectively, compared with unvaccinated mpox patients. In mpox patients with HIV infection, the odds of hospitalization among those who had received 1 JYNNEOS vaccine dose was 0.28 (95% CI = 0.05-0.91) times that of those who were unvaccinated. No mpox-associated hospitalizations were identified among persons infected with HIV who had received 2 JYNNEOS vaccine doses. To optimize durable immunity, all eligible persons at risk for mpox, especially those infected with HIV, should complete the 2-dose JYNNEOS series.

Comparing 7-Day Versus 6-8-Day Penicillin Treatment Intervals Among Pregnant People With Syphilis of Late or Unknown Duration: No Difference Found in Incidence of Congenital Syphilis.

Background: Guidelines recommend that pregnant patients with syphilis of late/unknown duration be treated with benzathine penicillin G, dosed as 3 weekly intramuscular injections (BPGx3) given ideally at strict 7-day intervals. Given limited pharmacokinetic data, it is unknown whether more flexible BPG treatment intervals might be effective in preventing congenital syphilis (CS). Methods: We used California surveillance data to identify birthing parent/infant dyads wherein the pregnant parent had syphilis of late/unknown duration between January 1, 2016 - June 30, 2019. We divided the dyads into 3 groups based on prenatal treatment: (1) BPGx3 at strict 7-day intervals, (2) BPGx3 at 6-8 day intervals, and (3) no/inadequate treatment. We then compared CS incidence among infants in each group. Results: We analyzed 1,092 parent/infant dyads: 607 (55.6%) in the 7-day treatment group, 70 (6.4%) in the 6-8 day treatment group, and 415 (38.0%) in the no/inadequate treatment group. The incidence proportion of infants meeting CS criteria in each group was, respectively, 5.6%, 5.7%, and 36.9%. Compared with BPGx3 at 7-day intervals, the odds of CS were 1.0 [95% CI 0.4-3.0] in the 6-8 day group and 9.8 [95% CI 6.6-14.7] in the no/inadequate treatment group. Conclusions: Prenatal BPGx3 at 6-8 days was no more likely to lead to CS in infants than 7-days. These findings hint that 6-8-day intervals might be adequate to prevent CS among pregnant people with syphilis of late/unknown duration. Consequently, it is possible that CS evaluation beyond an RPR at delivery may be unnecessary in asymptomatic infants whose parents received BPGx3 at 6-8 days.

Testing for Mycoplasma genitalium and Using Doxycycline as First-Line Therapy at Initial Presentations for Non-Gonococcal Urethritis (NGU) Correlate With Reductions in Persistent NGU.

We found that the odds of return clinic visits for persistent non-gonococcal urethritis (NGU) were significantly lower (odds ratio: .4; 95% confidence interval: .3-.6; P < .0001) after implementing (1) testing for Mycoplasma genitalium during initial evaluations for NGU and (2) switching from azithromycin to doxycycline as first-line NGU treatment.

Urine Tenofovir Levels Strongly Correlate With Virologic Suppression in Patients With Human Immunodeficiency Virus on Tenofovir Alafenamide-Based Antiretroviral Therapy.

We found that urine tenofovir (TFV) levels >1500 ng/mL strongly predict virologic suppression among people with human immunodeficiency virus taking tenofovir alafenamide (odds ratio, 5.66; 95% confidence interval, 1.59-20.14; P = .007). This suggests an existing point-of-care assay developed for tenofovir disoproxil fumarate will support adherence monitoring for patients on all TFV-based antiretrovirals.

Characterizing the Rise of Disseminated Gonococcal Infections in California, July 2020-July 2021.

BACKGROUND: California has experienced an increase in reported cases of disseminated gonococcal infection (DGI). Given significant morbidity associated with DGI and the ability of Neisseria gonorrhoeae to rapidly develop antibiotic resistance, characterization of these cases can inform diagnosis, management, and prevention of DGI. METHODS: As part of the public health response to increased reports of DGI, we used gonorrhea surveillance data reported to the California Department of Public Health to identify all DGI cases in a geographically-bound region. Standardized case report forms were used to collect epidemiologic risk factors and clinical information obtained from provider/laboratory reports, medical records, and patient interviews. RESULTS: From 1 July 2020 to 31 July 2021, we identified 149 DGI patients among 63 338 total gonorrhea infections, representing 0.24% of gonorrhea cases. Estimated incidence was 0.47 DGI cases per 100 000 person-years. Mean age of DGI patients was 40 years, and 75 (50%) were cisgender men, of whom only 13 were known to have male partners. Where reported, more than one-third (36%) used methamphetamine and nearly one-quarter (23%) experienced homelessness. Clinically, 61% lacked urogenital, pharyngeal, or rectal symptoms; 2 patients died in the hospital. Among 47 isolates from patients with antimicrobial susceptibility testing (AST) results available, all were susceptible to ceftriaxone and cefixime. CONCLUSIONS: Most DGI patients lacked urogenital symptoms and were not among populations for which routine gonorrhea screening is currently recommended. Expanding gonorrhea screening might prevent DGI. Cefixime is likely the best option if transitioning from parenteral to oral therapy when AST results are unavailable.

Texting Lost-to-follow-up PrEP Patients from a San Francisco Sexual Health Clinic.

It is critical to understand what happens when PrEP patients are lost-to-follow-up (LTFU) and, where appropriate, attempt to re-engage them in care with the goal of preventing future human immunodeficiency virus (HIV) acquisition. We evaluated the benefits and limitations of using text-based outreach to re-engage with LTFU PrEP patients and offer re-initiation of PrEP care. Using text-messaging, we surveyed San Francisco City Clinic patients who started PrEP from January 2015 to October 2019 and were LTFU by October 1, 2020. Our goals were to better understand (1) whether our patients remained on PrEP through another provider or source, (2) why patients choose to discontinue PrEP, and (3) whether text-based outreach could successfully re-engage such patients in care. Multiple-choice survey questions were analyzed quantitatively to determine the proportion of respondents selecting each option; free-text responses were analyzed qualitatively using an inductive approach to identify any additional recurring themes. Of 846 eligible survey recipients, 130 responded (overall response rate 15.4%). Forty-two respondents (32.3%) were still on PrEP through another provider while 88 (67.7%) were not. Common reasons for stopping PrEP included: COVID-19-related changes in sex life (32.3% of responses), concerns regarding side effects (17.7%), and the need to take a daily pill (8.3%). Free text responses revealed additional concerns regarding risk compensation. While 32 participants agreed to be contacted by City clinic staff for PrEP counseling, only 6 were reached by phone and none of the six subsequently restarted PrEP. We learned that text messaging is a possible approach to survey certain PrEP program participants to determine who is truly LTFU and off PrEP, and to better understand reasons for PrEP discontinuation. While such information could prove valuable as programs seek to address barriers to PrEP retention, efforts to improve acceptability and increase response rates would be necessary. We were less successful in re-engaging LTFU patients in PrEP care, suggesting that text-messaging may not be the optimal strategy for this purpose.

Correction: Consumer perceptions of antimicrobial use in animal husbandry: A scoping review.

[This corrects the article DOI: 10.1371/journal.pone.0261010.].

Geospatial Social Determinants of Health Correlate with Disparities in Syphilis and Congenital Syphilis Cases in California.

Syphilis and congenital syphilis (CS) are increasing in California (CA). From 2015 through 2019, for example, CA cases of early syphilis among reproductive-age females (15−44) and CS each increased by >200%. Certain populations­including people experiencing homelessness, using drugs, and/or belonging to certain racial/ethnic groups­have been disproportionately impacted. We hypothesized that geospatial social determinants of health (SDH) contribute to such health inequities. To demonstrate this, we geospatially described syphilis in CA using the Healthy Places Index (HPI). The HPI is a composite index that assigns a score to each CA census tract based on eight socioeconomic characteristics associated with health (education, housing, transportation, neighborhood conditions, clean environment, and healthcare access as well as economic and social resources). We divided CA census tracts into four quartiles based on HPI scores (with the lowest quartile having the least healthy socioeconomic and environmental conditions), then used 2013−2020 CA sexually transmitted diseases surveillance data to compare overall syphilis (among adults and adolescents) and CS case counts, incidence rates (per 100,000 population or live births), and incidence rate ratios (IRRs) among these quartiles. From 2013 to 2020, across all stages of syphilis and CS, disease burden was greatest in the lowest HPI quartile and smallest in the highest quartile (8308 cases (representing 33.2% of all incidents) versus 3768 (15.1%) for primary and secondary (P&S) syphilis; 5724 (31.6%) versus 2936 (16.2%) for early non-primary non-secondary (NPNS) syphilis; 11,736 (41.9%) versus 3026 (10.8%) for late/unknown duration syphilis; and 849 (61.9%) versus 57 (4.2%) for CS; all with p < 0.001). Using the highest HPI quartile as a reference, the IRRs in the lowest quartile were 17 for CS, 4.5 for late/unknown duration syphilis, 2.6 for P&S syphilis, and 2.3 for early NPNS syphilis. We thus observed a direct relationship between less healthy conditions (per HPI) and syphilis/CS in California, supporting our hypothesis that SDH correlate with disparities in syphilis, especially CS. HPI could inform allocation of resources to: (1) support communities most in need of assistance in preventing syphilis/CS cases and (2) reduce health disparities.

High Throughput UHPLC-MS-Based Lipidomics Using Vacuum Jacketed Columns.

Reversed-phase UHPLC-MS is extensively employed for both the profiling of biological fluids and tissues to characterize lipid dysregulation in disease and toxicological studies. With conventional LC-MS systems the chromatographic performance and throughput are limited due to dispersion from the fluidic connections as well as radial and longitudinal thermal gradients in the LC column. In this study vacuum jacketed columns (VJC), positioned at the source of the mass spectrometer, were applied to the lipidomic analysis of plasma extracts. Compared to conventional UHPLC, the VJC-based methods offered greater resolution, faster analysis, and improved peak intensity. For a 5 min VJC analysis, the peak capacity increased by 66%, peak tailing reduced by up to 34%, and the number of lipids detected increased by 30% compared to conventional UHPLC. The narrower peaks, and thus increased resolution, compared to the conventional system resulted in a 2-fold increase in peak intensity as well a significant improvement in MS and MS/MS spectral quality resulting in a 22% increase in the number of lipids identified. When applied to mouse plasma samples, reproducibility of the lipid intensities in the pooled QC ranged from 1.8-12%, with no related drift in tR observed.

Consumer perceptions of antimicrobial use in animal husbandry: A scoping review.

Antimicrobial use in animal agriculture is often perceived to play a role in the emerging threat of antimicrobial resistance. Increased consumer awareness of this issue places pressure on animal husbandry to adopt policies to reduce or eliminate antimicrobial use. We use a scoping review methodology to assess research on consumer perceptions of antimicrobial drugs in meat products in the United States, Canada, or the European Union. Evaluating peer-reviewed and grey literature, we included studies for assessment if they met these topical and geographic requirements, involved primary data collection, and were originally published in English. Our screening process identified 124 relevant studies. Three reviewers jointly developed a data charting form and independently charted the contents of the studies. Of the 105 studies that measured consumer concern, 77.1% found that consumers were concerned about antimicrobial use in meat production. A minority of studies (29.8% of all studies) queried why consumers hold these views. These studies found human health and animal welfare were the main reasons for concern. Antimicrobial resistance rarely registered as an explicit reason for concern. A smaller group of studies (23.3%) measured the personal characteristics of consumers that expressed concern about antimicrobials. Among these studies, the most common and consistent features of these consumers were gender, age, income, and education. Regarding the methodology used, studies tended to be dominated by either willingness-to-pay studies or Likert scale questionnaires (73.64% of all studies). We recommend consideration of qualitative research into consumer views on this topic, which may provide new perspectives that explain consumer decision-making and mentality that are lacking in the literature. In addition, more research into the difference between what consumers claim is of concern and their ultimate purchasing decisions would be especially valuable.

Concurrent COVID-19 and Acute HIV: A Case Report and Diagnostic Review.

A 26-year-old male presented to the emergency department feeling unwell in February of 2021 with symptoms including diaphoresis, loose stools, and loss of taste sensation. Workup not only confirmed a diagnosis of COVID-19 but also revealed discordant HIV test results, with a reactive fourth-generation antigen/antibody test but a negative HIV-1/2 differentiation immunoassay. Subsequent HIV viral load testing obtained two days later ultimately established a diagnosis of acute HIV (AHI). Screening for HIV and other sexually transmitted infections decreased during the COVID-19 pandemic. It is critical that providers (1) continue recommended screening for HIV as an essential service; (2) consider acute HIV in the differential when evaluating patients with acute viral syndromes; (3) recognize that AHI can occur concurrently with other infections, including COVID-19; and (4) understand the differential diagnosis for discordant HIV test results and know when HIV viral load testing is needed to resolve such discordant results.

High-Throughput UHPLC/MS/MS-Based Metabolic Profiling Using a Vacuum Jacketed Column.

In UHPLC, frictional heating from the eluent flowing through the column at pressures of ca. 10-15 Kpsi causes radial diffusion via temperature differences between the center of the column and its walls. Longitudinal dispersion also occurs due to temperature gradients between the inlet and outlet. These effects cause band broadening but can be mitigated via a combination of vacuum jacketed stainless steel tubing, reduced column end nut mass, and a constant temperature in the column from heating the inlet fitting. Here, vacuum jacketed column (VJC) technology, employing a novel column housing located on the source of the mass spectrometer and minimized tubing from the column outlet to the electrospray probe, was applied to profiling metabolites in urine. For a 75 s reversed-phase gradient separation, the average peak widths for endogenous compounds in urine were 1.2 and 0.6 s for conventional LC/MS and VJC systems, respectively. The peak tailing factor was reduced from 1.25 to 1.13 when using the VJC system compared to conventional UHPLC, and the peak capacity increased from 65 to 120, with a 25% increase in features detected in urine. The increased resolving power of the VJC system reduced co-elution, simplifying MS and MS/MS spectra, providing a more confident metabolite identification. The increased LC performance also gave more intense MS peaks, with a 10-120% increase in response, improving the quality of the MS data and detection limits. Reducing the LC gradient duration to 37 s gave peak widths of ca. 0.4 s and a peak capacity of 84.

Lower Urine Tenofovir Concentrations Among Individuals Taking Tenofovir Alafenamide Versus Tenofovir Disoproxil Fumarate: Implications for Point-of-Care Testing.

From directly observed therapy studies, urine tenofovir (TFV) levels were 74% lower when taking tenofovir alafenamide (TAF) vs tenofovir disoproxil fumarate. Urine TFV remains quantifiable across a range of TAF adherence patterns, but a separate point-of-care lateral flow immunoassay with a lower TFV threshold will be needed to support TAF adherence monitoring.

Brief Report: No Difference in Urine Tenofovir Levels in Patients Living With HIV on Unboosted Versus Dose-Adjusted Boosted Tenofovir Alafenamide.

BACKGROUND: Tenofovir alafenamide (TAF) is increasingly used in HIV treatment, with or without agents that require pharmacologic boosters such as ritonavir/cobicistat. Boosters increase TAF levels, so the TAF dose is lowered in single-pill combinations. We hypothesized that individuals on dose-adjusted boosted TAF would have similar urine tenofovir (TFV) concentrations to those on unboosted TAF. SETTING/METHODS: We collected urine samples from patients with HIV on TAF, with evidence of virologic suppression and high self-reported adherence at 2 San Francisco clinics from June 2019 to January 2020. We measured urine TFV levels by liquid chromatography/tandem mass spectrometry and used linear regression to compare natural log-transformed urine TFV levels for patients on boosted versus unboosted TAF. RESULTS: Our analysis included 30 patients on unboosted TAF (25 mg daily TAF) and 15 on boosted TAF (12 on 10 mg daily TAF and 3 on 25 mg daily TAF). Patients on unboosted vs. boosted TAF had similar baseline age, weight, sex, and creatinine. In unadjusted univariate linear regression, there were no significant differences in urine TFV levels based on presence/absence of boosting after TAF dose reduction to 10 mg (geometric mean ratio 1.07; 95% confidence interval: 0.53 to 2.16). This finding was unchanged in adjusted analysis. CONCLUSIONS: No significant differences in urine TFV levels were seen for patients on unboosted vs. boosted dose-reduced TAF. These results have important implications for our forthcoming point-of-care urine immunoassay for TAF, implying that separate adherence cutoffs will not be necessary for patients on boosters and dose-reduced TAF. A single POC TAF immunoassay will, thus, support monitoring on most TAF-based antiretroviral therapy.

Measuring the Impact of the COVID-19 Pandemic on Sexually Transmitted Diseases Public Health Surveillance and Program Operations in the State of California.

BACKGROUND: As public health personnel and resources are redirected to COVID-19, sexually transmitted diseases (STD) programs have been unable to sustain pre-COVID-19 activities. METHODS: We used California (CA) surveillance data to describe trends in case reporting for gonorrhea, chlamydia, and syphilis of any stage in the pre- versus post-COVID-19 eras (January-June 2019 and January-June 2020). We also analyzed data from an electronic survey administered by the CA STD Control Branch to local health jurisdictions in April, June, and September of 2020, assessing the impact of COVID-19 on STD programs. RESULTS: There were sharp declines in cases of all reportable bacterial STDs occurring in conjunction with the March 19, 2020 CA stay-at-home order, most of which did not return to baseline by July. Comparing January-June 2020 to January-June of 2019, there were decreases in reported cases of chlamydia (31%), late syphilis (19%), primary/secondary syphilis (15%), early nonprimary nonsecondary syphilis (14%), and gonorrhea (13%). The largest percentage declines in STD case reporting were among Hispanic, Asian/Pacific Islander, and Black persons. Seventy-eight percent of local health jurisdiction respondents indicated that half or more of their workforce had been redeployed to COVID-19 by September 2020. CONCLUSIONS: During the COVID-19 era, STD case reporting and programmatic functions have diminished throughout CA. Because this may contribute to decreases or delays in STD diagnosis and treatment-with resultant increases in STD transmission-providers and public health officials should prepare for potential increases in STD-related morbidity in the months and years to come.

Acute HIV at the Time of Initiation of Pre-exposure or Post-exposure Prophylaxis: Impact on Drug Resistance and Clinical Outcomes.

BACKGROUND: Initiating pre-exposure or post-exposure prophylaxis (PrEP/PEP) in the setting of undiagnosed acute HIV (AHI) could cause antiretroviral resistance. We sought to characterize clinical outcomes and drug resistance mutations among individuals prescribed PrEP/PEP with undiagnosed AHI at a San Francisco sexually transmitted disease clinic. SETTING: In our PrEP/PEP program, patients are tested for HIV using a point-of-care antibody test. If negative, patients are started on prophylaxis and screened for AHI using pooled HIV RNA (5-10 days turn-around). We used 2-drug PEP until 05/2016. METHODS: We identified patients who had as-yet-undiagnosed AHI on the day of PrEP/PEP start between 2011 and 2018, then used our clinical record and surveillance data to describe HIV resistance and clinical outcomes. RESULTS: Of 1758 PrEP and 2242 PEP starts, there were 7 AHI cases among PrEP users (0.40%) and 6 among PEP users (0.30%). Median times for linkage to HIV care, initiation of HIV treatment, and viral suppression were 7, 12, and 43 days. On initiation of HIV care, 3 patients (23%) were found to have an M184 mutation 7-12 days after starting PrEP/PEP. All 3 had genotyping performed on stored serum available from the date of PrEP/PEP start, each of which demonstrated wild-type virus. All 3 patients achieved durable viral suppression. CONCLUSIONS: Although rare (occurring <0.5% of the time), AHI in the setting of PrEP/2-drug PEP can result in an M184 within days. Even with M184, persons with AHI achieve viral suppression when rapidly linked to care and initiated on antiretroviral therapy. Providers should consider AHI screening when starting PrEP/PEP.

Agreement of sleep specialists with registered nurses' sleep study orders in supervised clinical practice.

STUDY OBJECTIVES: Incorporating registered nurses (RN-level) into obstructive sleep apnea (OSA) management decisions has the potential to augment the workforce and improve patient access, but the appropriateness of such task-shifting in typical practice is unclear. METHODS: Our medical center piloted a nurse triage program for sleep medicine referrals. Using a sleep specialist-designed decision-making tool, nurses triaged patients referred for initial sleep studies to either home sleep apnea test (HSAT) or in-laboratory polysomnography (PSG). During the first 5 months of the program, specialists reviewed all nurse triages. We compared agreement between specialists and nurses. RESULTS: Of 280 consultations triaged by nurses, nurses deferred management decisions to sleep specialists in 6.1% (n = 17) of cases. Of the remaining 263 cases, there was 88% agreement between nurses and specialists (kappa 0.80, 95% confidence interval 0.74-0.87). In the 8.8% (n = 23) of cases where supervising specialists changed sleep study type, specialists changed from HSAT to PSG in 16 cases and from PSG to HSAT in 7. The most common indication for change in sleep study type was disagreement regarding OSA pretest probability (n = 14 of 23). Specialists changed test instructions in 3.0% (n = 8) of cases, with changes either related to the use of transcutaneous carbon dioxide monitoring (n = 4) or adaptive servo-ventilation (n = 4). CONCLUSIONS: More than 80% of sleep study triages by registered nurses in a supervised setting required no sleep specialist intervention. Future research should focus on how to integrate nurses into the sleep medicine workforce in a manner that maximizes efficiency while preserving or improving patient outcomes.

HIV Seroconversion in the Era of Pharmacologic Prevention: A Case-Control Study at a San Francisco STD Clinic.

BACKGROUND: The comparative effectiveness of pre- and post-exposure prophylaxis (PrEP and PEP) for men who have sex with men (MSM) is unclear. SETTING: We conducted a case-control study of MSM who were initially HIV-uninfected during September 1, 2012-June 30, 2016 at San Francisco's only municipal sexually transmitted diseases (STDs) clinic. METHODS: Each case was matched with up to 3 controls based on age, baseline visit date, and follow-up time. The primary dependent variable was HIV seroconversion; the primary independent variable was exposure to PrEP, PEP, or neither. Conditional logistic regression was used to calculate odds ratios and 95% confidence intervals. RESULTS: Of 638 MSM (161 cases and 477 controls), 137 reported ever taking PrEP, 98 reported taking PEP-only, and 403 took neither. PrEP takers had more non-HIV sexually transmitted diseases during the analysis (72.3% vs. 55.1% vs. 42.4% P < 0.01) and were more likely to report receptive anal sex in the past 3 months (86.5% vs. 80.4% vs. 73.0%; P < 0.01). In the adjusted model, PrEP was associated with lower odds of HIV seroconversion (odds ratio 0.24; 95% confidence interval: 0.13 to 0.46) while PEP use had no effect on HIV acquisition compared with taking neither. CONCLUSIONS: MSM who ever used PrEP demonstrated equal or higher sexual risk compared with those using neither PrEP nor PEP but had 76% lower odds of HIV seroconversion. MSM who used PEP but never PrEP were no less likely to seroconvert than those using neither. MSM should be offered PrEP. PEP users with ongoing risk of HIV infection should be connected to PrEP after PEP.