Clinical presentation and virological assessment of hospitalized cases of coronavirus disease 2019 in a travel-associated transmission cluster

Roman Woelfel; Victor Max Corman; Wolfgang Guggemos; Michael Seilmaier; Sabine Zange; Marcel A Mueller; Daniela Niemeyer; Patrick Vollmar; Camilla Rothe; Michael Hoelscher; Tobias Bleicker; Sebastian Bruenink; Julia Schneider; Rosina Ehmann; Katrin Zwirglmaier; Christian Drosten; Clemens Wendtner

Seroconversion was detected by IgG and IgM immunofluorescence using cells expressing the spike protein of SARS-CoV-2 and a virus neutralization assay using SARS-CoV-2 ( Table 3 ). In early sera, taken between day 3 and 6, none of the patients showed detectable antibody. The patients monitored long enough to yield a serum sample after two weeks all showed neutralizing antibodies, the titer levels of which did not suggest any correlation with clinical courses. Of note, case #4, with the lowest virus neutralization titer at end of week 2, seemed to shed virus from stool over prolonged time (Figure 2 D) . Results on differential recombinant immunofluorescence assay indicated no significant rise in titer against the four endemic human Coronaviruses (Table S1) .