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1.
Viruses ; 12(7)2020 07 07.
Article in English | MEDLINE | ID: covidwho-639283

ABSTRACT

Standard precautions to minimize the risk of SARS-CoV-2 transmission implies that infected cell cultures and clinical specimens may undergo some sort of inactivation to reduce or abolish infectivity. We evaluated three heat inactivation protocols (56 °C-30 min, 60 °C-60 min and 92 °C-15 min) on SARS-CoV-2 using (i) infected cell culture supernatant, (ii) virus-spiked human sera (iii) and nasopharyngeal samples according to the recommendations of the European norm NF EN 14476-A2. Regardless of the protocol and the type of samples, a 4 Log10 TCID50 reduction was observed. However, samples containing viral loads > 6 Log10 TCID50 were still infectious after 56 °C-30 min and 60 °C-60 min, although infectivity was < 10 TCID50. The protocols 56 °C-30 min and 60 °C-60 min had little influence on the RNA copies detection, whereas 92 °C-15 min drastically reduced the limit of detection, which suggests that this protocol should be avoided for inactivation ahead of molecular diagnostics. Lastly, 56 °C-30 min treatment of serum specimens had a negligible influence on the results of IgG detection using a commercial ELISA test, whereas a drastic decrease in neutralizing titers was observed.


Subject(s)
Betacoronavirus , Containment of Biohazards/methods , Coronavirus Infections/virology , Pneumonia, Viral/virology , Serologic Tests/methods , Virus Inactivation , Antibodies, Neutralizing/immunology , Betacoronavirus/immunology , Containment of Biohazards/standards , Coronavirus Infections/diagnosis , Coronavirus Infections/prevention & control , Enzyme-Linked Immunosorbent Assay , Hot Temperature , Humans , Neutralization Tests , Pandemics/prevention & control , Pneumonia, Viral/diagnosis , Pneumonia, Viral/prevention & control , Serologic Tests/standards
2.
Antiviral Res ; 181: 104880, 2020 09.
Article in English | MEDLINE | ID: covidwho-645374

ABSTRACT

We investigated the distribution of antibodies neutralizing SARS-CoV-2 according to age, sex or blood group in French blood donors. In 464 samples collected before the emergence of SARS-CoV-2 (2017 and 2018), our virus neutralization assay had a 100% specificity. It was used to test 998 samples collected from blood donors during the last week of March or the first week of April 2020. As expected at this stage of the outbreak, the prevalence was low (2.7%) and, importantly, criteria for blood donation imply that the vast majority of seropositives had asymptomatic or pauci-symptomatic SARS-CoV-2 infections. Seroprevalence values did not differ significantly among age groups (but were slightly higher in donors <30yo and ≥60yo), and between males and females (2.82% vs 2.69%), unlike what has been observed regarding hospitalizations admission to ICU and death rates in France. By contrast, we observed that the proportion of seropositives was significantly lower in group O donors (1.32% vs 3.86% in other donors, p = 0.014). We conclude that virus infection seems to occur with a similar incidence in men and women among French blood donors, but that blood group O persons are less at risk of being infected and not only of suffering from severe clinical presentations, as previously suggested.


Subject(s)
Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Betacoronavirus/immunology , Coronavirus Infections/virology , Pneumonia, Viral/virology , Adult , Blood Donors , Blood Group Antigens , Coronavirus Infections/epidemiology , Female , France/epidemiology , Hospitalization , Humans , Incidence , Intensive Care Units , Male , Middle Aged , Pandemics , Pneumonia, Viral/epidemiology , Risk , Sensitivity and Specificity , Seroepidemiologic Studies , Young Adult
3.
Emerg Infect Dis ; 26(9)2020 09.
Article in English | MEDLINE | ID: covidwho-614160

ABSTRACT

We spotted severe acute respiratory syndrome coronavirus 2 on polystyrene plastic, aluminum, and glass for 96 hours with and without bovine serum albumin (3 g/L). We observed a steady infectivity (<1 log10 drop) on plastic, a 3.5 log10 decrease on glass, and a 6 log10 drop on aluminum. The presence of proteins noticeably prolonged infectivity.


Subject(s)
Betacoronavirus/isolation & purification , Coronavirus Infections/transmission , Disease Transmission, Infectious , Fomites/virology , Pneumonia, Viral/transmission , Aluminum/analysis , Coronavirus Infections/virology , Glass/analysis , Humans , Pandemics , Plastics/analysis , Pneumonia, Viral/virology , Time Factors
4.
Viruses ; 12(6)2020 06 08.
Article in English | MEDLINE | ID: covidwho-574875

ABSTRACT

Clinical samples collected in coronavirus disease 19 (COVID-19), patients are commonly manipulated in biosafety level 2 laboratories for molecular diagnostic purposes. Here, we tested French norm NF-EN-14476+A2 derived from European standard EN-14885 to assess the risk of manipulating infectious viruses prior to RNA extraction. SARS-CoV-2 cell-culture supernatant and nasopharyngeal samples (virus-spiked samples and clinical samples collected in COVID-19 patients) were used to measure the reduction of infectivity after 10 minute contact with lysis buffer containing various detergents and chaotropic agents. A total of thirteen protocols were evaluated. Two commercially available formulations showed the ability to reduce infectivity by at least 6 log 10, whereas others proved less effective.


Subject(s)
Betacoronavirus/drug effects , Coronavirus Infections/virology , Pneumonia, Viral/virology , Virus Inactivation/drug effects , Animals , Betacoronavirus/genetics , Betacoronavirus/isolation & purification , Betacoronavirus/physiology , Cell Culture Techniques/methods , Chlorocebus aethiops , Containment of Biohazards/methods , Containment of Biohazards/standards , Humans , Nasopharynx/virology , Pandemics , RNA, Viral/isolation & purification , Specimen Handling/methods , Vero Cells , Viral Load/methods
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