Evaluation and validation of an RT-PCR assay for specific detection of monkeypox virus (MPXV).

Monkeypox virus (MPXV) is a zoonotic orthopoxvirus within the Poxviridae family. MPXV is endemic to Central and West Africa. However, the world is currently witnessing an international outbreak with no clear epidemiological links to travel or animal exposure and with ever-increasing numbers of reported cases worldwide. Here, we evaluated and validated a new, sensitive, and specific real-time PCR-assay for MPXV diagnosis in humans and compare the performance of this novel assay against a Food & Drug Administration-cleared pan-Orthopox RT-PCR assay. We determined specificity, sensitivity, and analytic performance of the PKamp™ Monkeypox Virus RT-PCR assay targeting the viral F3L-gene. In addition, we further evaluated MPXV-PCR-positive specimens by viral culture, electron microscopy, and viral inactivation assays. The limit of detection was established at 7.2 genome copies/reaction, and MPXV was successfully identified in 20 clinical specimens with 100% correlation against the reference method with 100% sensitivity and specificity. Our results demonstrated the validity of this rapid, robust, and reliable RT-PCR assay for specific and accurate diagnosis of MPXV infection in human specimens collected both as dry swabs and in viral transport media. This assay has been approved by NYS Department of Health for clinical use.

Real-Time Investigation of a Large Nosocomial Influenza A Outbreak Informed by Genomic Epidemiology.

BACKGROUND: Nosocomial respiratory virus outbreaks represent serious public health challenges. Rapid and precise identification of cases and tracing of transmission chains is critical to end outbreaks and to inform prevention measures. METHODS: We combined conventional surveillance with influenza A virus (IAV) genome sequencing to identify and contain a large IAV outbreak in a metropolitan healthcare system. A total of 381 individuals, including 91 inpatients and 290 healthcare workers (HCWs), were included in the investigation. RESULTS: During a 12-day period in early 2019, infection preventionists identified 89 HCWs and 18 inpatients as cases of influenza-like illness (ILI), using an amended definition without the requirement for fever. Sequencing of IAV genomes from available nasopharyngeal specimens identified 66 individuals infected with a nearly identical strain of influenza A H1N1pdm09 (43 HCWs, 17 inpatients, and 6 with unspecified affiliation). All HCWs infected with the outbreak strain had received the seasonal influenza virus vaccination. Characterization of 5 representative outbreak viral isolates did not show antigenic drift. In conjunction with IAV genome sequencing, mining of electronic records pinpointed the origin of the outbreak as a single patient and a few interactions in the emergency department that occurred 1 day prior to the index ILI cluster. CONCLUSIONS: We used precision surveillance to delineate a large nosocomial IAV outbreak, mapping the source of the outbreak to a single patient rather than HCWs as initially assumed based on conventional epidemiology. These findings have important ramifications for more-effective prevention strategies to curb nosocomial respiratory virus outbreaks.