Histological Features Associated With Human Mpox Virus Infection in 2022 Outbreak in a Nonendemic Country.

Skin histology of papules and pustules from 5 men having sex with men with mpox infection showed viral intracytoplasmic cytopathic changes, interface dermatitis, marked inflammatory dermic infiltrate including superficial neutrophils and perivascular and periadnexal deep lymphocytes. Histologic description of mpox lesions improves our understanding about clinical presentations and may have some therapeutic implications.

Contribution of rapid lateral flow assays from capillary blood specimens to the diagnosis of COVID-19 in symptomatic healthcare workers: a pilot study in a university hospital, Paris, France.

BACKGROUND: This study aimed to assess, by rapid tests, the immune status against COVID-19 among Healthcare Workers (HCW) with history of symptoms, and for whom SARS-CoV-2 detection was either not documented or negative. METHODS: Whole blood by finger prick and serum samples were taken from HCW for use with 2 rapid lateral flow tests and an automated immunoassay. RESULTS: Seventy-two HCWs were included, median duration between symptoms onset and serology sampling was 68 days. Anti-SARS-CoV-2 antibodies were detected by rapid test in 11 HCW (15.3%) and confirmed in the 10 with available serum by the automated immunoassay. The frequency of ageusia or anosmia was higher in participants with SARS-CoV-2 antibodies (P = 0.0006 and P = 0.029, respectively). CONCLUSIONS: This study, among symptomatic HCW during the first wave in France, showed that 15% had IgG anti-SARS-CoV-2, a higher seroprevalence than in the general population. Rapid lateral flow tests were highly concordant with automated immunoassay.

Performance evaluation of two SARS-CoV-2 IgG/IgM rapid tests (Covid-Presto and NG-Test) and one IgG automated immunoassay (Abbott).

The aim of this study was to assess the analytical performances, sensitivity and specificity, of two rapid tests (Covid- Presto® test rapid Covid-19 IgG/IgM and NG-Test® IgM-IgG COVID-19) and one automated immunoassay (Abbott SARS-CoV-2 IgG) for detecting anti- SARS-CoV-2 antibodies. This study was performed with: (i) a positive panel constituted of 88 SARS-CoV-2 specimens collected from patients with a positive SARS-CoV-2 RT-PCR, and (ii) a negative panel of 120 serum samples, all collected before November 2019, including 64 samples with a cross-reactivity panel. Sensitivity of Covid-Presto® test for IgM and IgG was 78.4% and 92.0%, respectively. Sensitivity of NG-Test® for IgM and IgG was 96.6% and 94.9%, respectively. Sensitivity of Abbott IgG assay was 96.5% showing an excellent agreement with the two rapid tests (κ = 0.947 and κ = 0.936 for NGTest ® and Covid-Presto® test, respectively). An excellent agreement was also observed between the two rapid tests (κ = 0.937). Specificity for IgM was 100% and 86.5% for Covid-Presto® test and NG-Test®, respectively. Specificity for IgG was 92.0%, 94.9% and 96.5% for Covid-Presto®, NGTest ®, and Abbott, respectively. Most of the false positive results observed with NG-Test® resulted from samples containing malarial antibodies. In conclusion, performances of these 2 rapid tests are very good and comparable to those obtained with automated immunoassay, except for IgM specificity with the NG-Test®. Thus, isolated IgM should be cautiously interpreted due to the possible false-positive reactions with this test. Finally, before their large use, the rapid tests must be reliably evaluated with adequate and large panel including early seroconversion and possible cross-reactive samples.