ABSTRACT
A concern has been raised that the persistent COVID-19 infection in an immunocompromised host can be the source of the SARS-CoV-2 variants. This is the case of a 61-year-old man in complete remission of a follicular lymphoma after six cycles of rituximab and bendamustine with additional two cycles of rituximab completed eight months prior to the episode of COVID-19 pneumonia. The patient's respiratory failure was long-lasting, and required mechanical ventilation until day 75. Acquired immunity tested negative throughout the observational period. The viral RNA was detectable until day 100 while the infectious virus was isolated until day 79. Seven haplotypes were identified and the non-synonymous mutations accumulated in the spike gene which included E484Q and S494P. In the management of COVID-19 cases with suppressed immune statuses, initial evaluation of existing immunity and monitoring for infectiousness throughout the clinical course including the convalescent stage may be necessary.
ABSTRACT
Green tea extracts effectively inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in vitro in a dose-dependent manner. Ten-fold serially diluted solutions of catechin mixture reagent from green tea were mixed with the viral culture fluid at a volume ratio of 9:1, respectively, and incubated at room temperature for 5 min. The solution of 10 mg/mL catechin reagent reduced the viral titer by 4.2 log and 1.0 mg/mL solution by one log. Pre-infection treatment of cells with the reagent alone did not affect viral growth. In addition, cells treated with only the reagent were assayed for host cell viability using the WST-8 system, and almost no host cell damage by the treatment was observed. These findings suggested that the direct treatment of virus with the reagent before inoculation decreased the viral activity and that catechins might have the potential to suppress SARSCoV-2 infection.