Seroprevalence of SARS-CoV-2 in blood donors from the Lodi Red Zone and adjacent Lodi metropolitan and suburban area.

OBJECTIVES: To define the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in blood donors (referred to the first lockdown area (Lodi Red-Zone) of the Lombardy region and in a contiguous area that was not included in the first lockdown); to define the agreement between a commercial serological assay and a reference microneutralization assay; and to evaluate the persistence of SARS-CoV-2 neutralizing antibodies in a cohort of blood donors. METHODS: Blood donors referred to the first lockdown area in Lombardy Region and the neighbouring area were analysed for SARS-CoV-2 IgG-specific antibodies during the period 18 March to 24 June 2020. Serum samples were analysed using both a chemiluminescent immunoassay (LIAISON® SARS-CoV-2 S1/S2 IgG, DiaSorin) for the quantitative characterization of SARS-CoV-2 anti-S1 and anti-S2 IgG antibodies and a neutralizing antibodies (NT-Abs) assay. RESULTS: In the period from 18 March to 24 June, 1922 blood donors were tested for the presence of SARS-CoV-2 IgG showing a prevalence of 378/1922 (19.7%). A subgroup of 1139 blood donors were tested in parallel with a SARS-CoV-2 IgG assay and a microneutralization assay showing a prevalence of 22.2% and 21.6%, respectively. SARS-CoV-2 IgG quantification was correlated with NT-Abs titres. In 78.2% of participants the NT-Abs titre was maintained, but in 15.8% it decreased by one four-fold dilution and in 6.0% it increased by one four-fold dilution. CONCLUSIONS: The duration of immunity of SARS-CoV-2 is crucial for the course of the pandemic and for this reason the monitoring of NT Abs is important. Despite a stable NT-Abs titre being observed in the majority of blood donors, our findings need to be validated in a long-term period of follow up.

Residual SARS-CoV-2 RNA in nasal swabs of convalescent COVID-19 patients: Is prolonged quarantine always justified?

Real-time reverse transcription PCR is currently the most sensitive method to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Defining whether a patient could be contagious or not contagious in the presence of residual SARS-CoV-2 RNA is of extreme importance in the context of public health. In this prospective multicenter study, virus isolation was prospectively attempted in 387 nasal swabs from clinically recovered patients showing low viral load (quantification cycle, Cq, value greater than 30). The median Cq value was 36.8 (range 30.0-39.4). Overall, a cytopathic effect was detected in nine samples, corresponding to a culture positivity rate of 2.3% (9/387). The results of this study help to dissect true virus replication and residual viral RNA detection in recovered patients.

Plasma from donors recovered from the new Coronavirus 2019 as therapy for critical patients with COVID-19 (COVID-19 plasma study): a multicentre study protocol.

Since the end of 2019, a new coronavirus strain has been reported in the Chinese province of Wuhan, indicated as 2019-nCoV or SARS-CoV-2. In February 2020, the first case of transmission on Italian soil was reported. On March 09, 2020, at the time of protocol design, the Italian Ministry of Health reported 10,149 people who had contracted the virus; of these, 8514 were positive, of which 5038 were hospitalized with symptoms (59.2%) and 877 in intensive care (10.3%), while the remaining 2599 were in home isolation; 631 were deceased (6.2%) and 1004 healed (9.9%). To date there are no studies in the literature that demonstrate its feasibility and efficacy in the context of the worldwide SARS-CoV-2 epidemic. Based upon the little existing evidence, we planned to assess the efficacy of the infusion of hyperimmune plasma in COVID-19 patients in a one-arm proof-of-concept clinical trial. The primary objective of our study is to evaluate the efficacy of the administration of plasma taken from convalescent donors of COVID-19 to critically ill patients with COVID-19 in terms of their survival. Death from any cause will be considered. The main limit of this study is its one-arm proof-of-concept design with only 43 patients enrolled. However, in the absence of previous evidence, larger and/or randomized trials did not appear to be ethically acceptable. Moreover, the results from this study, if encouraging, will allow us to plan further informed large clinical trials. Trial registration: NCT04321421 March 23, 2020.