Discontinuation of Transmission Precautions for COVID-19 Patients: Polymerase Chain Reaction Diagnostics, Patient Delays, and Cycle Threshold Values.

BACKGROUND: The decision of when it is safe to discontinue transmission-based precautions for SARS-CoV-2 coronavirus disease 2019 (COVID-19) hospitalized patients has been controversial. The Centers for Disease Control and Prevention offered reverse transcriptase polymerase chain reaction (PCR) diagnostic test- or symptom-based guidelines. METHODS: A retrospective chart review of Vidant Health system, Eastern North Carolina, was conducted. Length of stay, days in isolation unit, and date appropriate for discharge or isolation discontinuation based on the symptom-based strategy were recorded. RESULTS: Of 196 COVID hospitalized patients, 34 had repeated COVID PCR tests 3 or more days from their first positive test result. Half of these patients experienced delays in release from transmission-based precautions because of repeated positive PCR test results and use of the test-based approach. This resulted in an additional 166 days of hospitalization, costing an estimated $415,000. Furthermore, 2 subjects had a combined 16-day delay in necessary medical procedures. Most of the COVID PCR platforms yield quantitative results in the form of cycle threshold (Ct) values, the number of cycles needed to detect the genome. These values have also been used to assess whether patients are likely to remain contagious. None of our patients who met the criteria for symptom-based strategy for transmission-based precaution discontinuation had positive PCR test results with Ct values lower than 25, but 4 had Ct values lower than 30. CONCLUSIONS: Concerns surround immunocompromised patients and those treated with steroids who might be delayed or incapable of stopping viral replication and thus remain contagious. Our results suggest that clinicians use all available data including Ct values to evaluate the safety of discontinuation of transmission precautions.

miRNAs and their roles in KSHV pathogenesis.

Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent of Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman Disease (MCD). Recent mechanistic advances have discerned the importance of microRNAs in the virus-host relationship. KSHV has two modes of replication: lytic and latent phase. KSHV entry into permissive cells, establishment of infection, and maintenance of latency are contingent upon successful modulation of the host miRNA transcriptome. Apart from host cell miRNAs, KSHV also encodes viral miRNAs. Among various cellular and molecular targets, miRNAs are appearing to be key players in regulating viral pathogenesis. Therefore, the use of miRNAs as novel therapeutics has gained considerable attention as of late. This innovative approach relies on either mimicking miRNA species by identical oligonucleotides, or selective silencing of miRNA with specific oligonucleotide inhibitors. Here, we provide an overview of KSHV pathogenesis at the molecular level with special emphasis on the various roles miRNAs play during virus infection.

Evaluation of the bag-mediated filtration system as a novel tool for poliovirus environmental surveillance: Results from a comparative field study in Pakistan.

Poliovirus (PV) environmental surveillance (ES) plays an important role in the global eradication program and is crucial for monitoring silent PV circulation especially as clinical cases decrease. This study compared ES results using the novel bag-mediated filtration system (BMFS) with the current two-phase separation method. From February to November 2016, BMFS and two-phase samples were collected concurrently from twelve sites in Pakistan (n = 117). Detection was higher in BMFS than two-phase samples for each Sabin-like (SL) PV serotype (p<0.001) and wild PV type 1 (WPV1) (p = 0.065). Seventeen sampling events were positive for WPV1, with eight discordant in favor of BMFS and two in favor of two-phase. A vaccine-derived PV type 2 was detected in one BMFS sample but not the matched two-phase. After the removal of SL PV type 2 (SL2) from the oral polio vaccine in April 2016, BMFS samples detected SL2 more frequently than two-phase (p = 0.016), with the last detection by either method occurring June 12, 2016. More frequent PV detection in BMFS compared to two-phase samples is likely due to the greater effective volume assayed (1620 mL vs. 150 mL). This study demonstrated that the BMFS achieves enhanced ES for all PV serotypes in an endemic country.