Mpox in people with past infection or a complete vaccination course: a global case series.

BACKGROUND: Since May, 2022, a large global outbreak of human mpox (formerly known as monkeypox) has predominantly affected men who have sex with men. The strain responsible, Clade IIb, has mutated substantially from precursors originating from the 2017-18 outbreak in Nigeria. Immunity to smallpox, another orthopoxvirus, via previous infection or vaccination provides lifelong immunity. However, since the 2022 mpox outbreak, recent clusters were described in individuals with presumed immunity through recent infection or vaccination. We aim to describe the epidemiological and clinical characteristics of mpox in individuals with past infection or vaccination to improve the understanding of this disease in the setting of previous immunity. METHODS: In this global case series, international collaborators from nine countries provided data on individuals with PCR-confirmed mpox after documented previous infection or vaccination between May 11, 2022, and June 30, 2023. We excluded cases that could not confirm vaccination status or cases with partial immunisation or any doses received before the current multi-national mpox outbreak (cutoff date May 1, 2022). Data were collected via a case report spreadsheet that reported on dates of infection and vaccination, route of immunisation, demographic characteristics, clinical findings, HIV status, concomitant sexually transmitted infections, and markers of disease severity (mpox severity score system). We describe case epidemiology, clinical course, and mpox severity scores; all analyses were descriptive. FINDINGS: We report mpox infections in 37 gay and bisexual men who have sex with men: seven individuals had mpox reinfections, 29 individuals had mpox infections that occurred after two appropriately spaced Modified Vaccinia Ankara-Bavarian Nordic vaccine courses, and one individual had an infection that met the criteria for both reinfection and infection after vaccination. The median age of individuals was 36 years (IQR 30-45; range 21-58). Those with natural immunity after initial infection had a shorter disease course with less mucosal disease upon reinfection than with their initial infection. Infections post-vaccination were characterised by few lesions, little mucosal disease, and minimal analgesia requirements; two people received oral tecovirimat. Overall, there were no deaths, no bacterial superinfections, and all individuals were managed in the ambulatory clinic with one hospital admission for a necrotising neck lesion. INTERPRETATION: The epidemiology of people with mpox reinfection or infection post-vaccination was similar to other published cohorts during the 2022 outbreak-predominantly young, sexually active gay and bisexual men who have sex with men. Clinical features and outcomes of repeat infection and infection after vaccination appear to be less clinically severe than those described in 2022 case literature. Specifically, compared with the 2022 case series, these individuals in the present study had fewer confluent lesions, less mucosal involvement, reduced analgesia requirement, and fewer admissions. Natural immunity and vaccine-induced immunity are not fully protective against mpox infection. However, in this small series both disease duration and severity appear to be reduced. FUNDING: None.

COVID-19 Antibody Prevalence From July to September 2020: One Army Infantry Brigade's Experience.

OBJECTIVES: Lab companies developed serology tests for antibody detection of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) with United States Food and Drug Administration (FDA) emergency use authorization. Antibody detection uses purified proteins of SARS-CoV-2 to determine antibody binding via enzyme-linked immunosorbent assay, chemiluminescent immunoassay (CLIA), or colloidal gold-based immunochromatographic assay. With the advent of coronavirus disease 2019 (COVID-19), nucleic acid amplification technology (NAAT) SARS-CoV-2 testing for active infection was not widely available to healthy, active-duty Soldiers. The purpose of this surveillance survey was to determine the prevalence of prior SARS-CoV-2 infection and symptoms of COVID-19 within a mechanized infantry brigade. MATERIALS AND METHODS: Active-duty military Servicemembers (= 18 years) from a mechanized infantry brigade provided serum samples for testing for the Elecsys® Anti-SARS-CoV-2 qualitative antibody test from June to September 2020 at Joint Base Lewis McChord (JBLM). In addition, participants filled out a questionnaire for symptoms and exposure to COVID-19 from January to September 2020. The surveillance team collected and analyzed antibody testing results and questionnaires from participants for antibody positivity rates and symptom prevalence. RESULTS: A total of 264 participants were tested, with one (0.4%) participant testing positive for the SARS-CoV-2 antibody. On the questionnaire, 144 of 264 (54.5%) endorsed symptoms of COVID-19 from January to September 2020. The most common symptoms were headache (35%), rhinorrhea (34%), cough (35%), and sore throat (31%). A total of 31 respondents (12%) had been quarantined as a trace contact to a COVID-19 positive patient. CONCLUSIONS: While there are limitations inherent to SARS-CoV-2 antibody testing and the survey, prevalence of prior SARS-CoV-2 infection is low. In this sample, symptoms for COVID-19 were prevalent with significant days of duty lost. Prevalence of prior SARS-CoV-2 infection in this sample may be generalizable to the larger brigade. Prevalence of symptoms of possible COVID-19 are not generalizable to the larger brigade. There is utility to further studies of SARS-CoV-2 antibody prevalence in military populations for purposes of vaccination triaging and deployment readiness.