BACKGROUND: The extent to which infections may have been undetected in an epicenter of the 2022 mpox outbreak is unknown. METHODS: A serosurvey (July and August 2022) assessed the seroprevalence and correlates of mpox infection among a diverse sample of asymptomatic patients with no prior mpox diagnoses and no known histories of smallpox or mpox vaccination. We present seropositivity stratified by participant characteristics collected via survey. RESULTS: Two-thirds of 419 participants were cismen (281 of 419), of whom 59.1% (166 of 281) reported sex with men (MSM). The sample also included 109 ciswomen and 28 transgender/gender nonconforming/nonbinary individuals. Overall seroprevalence was 6.4% (95% confidence interval [CI], 4.1%-8.8%); 3.7% among ciswomen (95% CI, 1.0%-9.1%), 7.0% among cismen with only ciswomen partners (95% CI, 2.0%-11.9%), and 7.8% among MSM (95% CI, 3.7%-11.9%). There was little variation in seroprevalence by race/ethnicity, age group, HIV status, or number of recent sex partners. No participants who reported close contact with mpox cases were seropositive. Among participants without recent mpox-like symptoms, 6.3% were seropositive (95% CI, 3.6%-9.0%). CONCLUSIONS: Approximately 1 in 15 vaccine-naive people in our study had antibodies to mpox during the height of the NYC outbreak, indicating the presence of asymptomatic infections that could contribute to ongoing transmission.

CONTEXT: Kalanchoe pinnata (Lam.) Pers. (Crassulaceae) is a succulent plant that is known for its traditional antivirus and antibacterial usage. OBJECTIVE: This work examines two compounds identified from the K. pinnata plant for their antivirus activity against human alphaherpesvirus (HHV) 1 and 2 and vaccinia virus (VACV). MATERIALS AND METHODS: Compounds KPB-100 and KPB-200 were isolated using HPLC and were identified using NMR and MS. Both compounds were tested in plaque reduction assay of HHV-2 wild type (WT) and VACV. Both compounds were then tested in virus spread inhibition and virus yield reduction (VYR) assays of VACV. KPB-100 was further tested in viral cytopathic effect (CPE) inhibition assay of HHV-2 TK-mutant and VYR assay of HHV-1 WT. RESULTS: KPB-100 and KPB-200 inhibited HHV-2 at IC50 values of 2.5 and 2.9 mug/mL, respectively, and VACV at IC50 values of 3.1 and 7.4 mug/mL, respectively, in plaque reduction assays. In virus spread inhibition assay of VACV KPB-100 and KPB-200 yielded IC50 values of 1.63 and 13.2 mug/mL, respectively, and KPB-100 showed a nearly 2-log reduction in virus in VYR assay of VACV at 20 mug/mL. Finally, KPB-100 inhibited HHV-2 TK- at an IC50 value of 4.5 mug/mL in CPE inhibition assay and HHV-1 at an IC90 of 3.0 mug/mL in VYR assay. DISCUSSION AND CONCLUSION: Both compounds are promising targets for synthetic optimization and in vivo study. KPB-100 in particular showed strong inhibition of all viruses tested.