Digital RT-PCR Chip method for detection of SARS-CoV-2 virus.

The "gold standard" method for detection of SARS-CoV-2 is the real time reverse transcription-polymerase chain reaction, but due to pre-analytical and technical limitations, biological samples with low viral load are not sometimes detected. For this purpose a digital RT-PCR method on-chip was developed for detection of the SARS-CoV-2 virus, using two TaqMan™ Assays for quantification of the N Protein (Nucleocapsid) and the S Protein (Spike), and the QuantStudio™ 3D Digital PCR instrument. The method was applied to assess the nasopharyngeal swabs of asymptomatic subjects recruited in the UNICORN Study. The digital RT-PCR method is characterized by a higher sensitivity than the RT-qPCR method, even if performed with the same TaqMan™, and could be a promising tool for SARS-CoV-2 viral load quantification.

Time Length of Negativization and Cycle Threshold Values in 182 Healthcare Workers with Covid-19 in Milan, Italy: An Observational Cohort Study.

Background: Coronavirus Disease 2019 (COVID-19) has rapidly spread worldwide, becoming an unprecedented public health emergency. Rapid detection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) suspected cases is crucial to control the spread of infection. We aimed to evaluate the time length of negativization from the onset of symptoms in healthcare workers (HCWs) with COVID-19, and to evaluate significant variations in cycle threshold (CT) values and gene positivity (E, RdRP, and N genes) among positive individuals who returned to work. Methods: We retrospectively analyzed a consecutive cohort of 182 SARS-CoV-2-positive HCWs in Milan, from 16 March to 30 April 2020. Nasopharyngeal swabs were tested by RT-PCR. Results: Asymptomatic HCWs were 17.6% (32/182), and 58 healed at 30 April 2020. The median time length of negativization was 4 weeks (35% of symptomatic versus 40% of asymptomatic HCWs). Four HCWs, healed at 30 April, turned positive within three weeks during controls set up in the work unit. Three-gene positivity had the greatest variability, and increasing CT values from single- to three-gene positivity among all age groups were observed. Conclusions: Self-isolation longer than two weeks and prolonged follow-up periods for the staff returning to work after COVID-19 could be the most suitable choices to counter the SARS-CoV-2 spread. Further studies are needed to investigate infectiousness profiles among positive individuals.

Sustained response to combination therapy in patients with chronic hepatitis C who failed to respond to interferon.

BACKGROUND/AIMS: The best treatment for chronic hepatitis C patients who do not respond to interferon is still unknown. Reported rates of response to treatment vary as the result of heterogeneous definitions of non-responders and small study size. METHODS: One hundred nineteen hepatitis C virus (HCV) RNA-positive non-responders to high-dose interferon monotherapy received alpha-interferon, 5 MU tiw plus oral ribavirin, 1000-1200 mg/day for 48 weeks (Group A, n=74) or alpha-interferon, 5 MU daily for 4 weeks, followed by 5 MU tiw plus oral ribavirin, 1000-1200 mg/day for 44 weeks (Group B, n=45) according to the Institution where they were followed. Persistently normal alanine aminotransferase and negative HCV RNA up to 72 weeks from treatment onset defined a sustained response. RESULTS: Eighteen patients discontinued treatment (13 developed anemia, two mucositis, one granulocytopenia; two were dropouts), none for serious adverse events. There were 24 (20%) sustained responders, with similar final response rates in Groups A and B. Sustained response was more frequent in patients aged