Qing Fei Pai Du Tang, a Chinese multi-herbal medicine formulated against COVID-19, elevates the plasma levels of IL-1β, IL-18, TNF-α, and IL-8

There are currently no specific vaccine or drugs proven to be effective against COVID-19. Traditional Chinese herbal medicine has been integrated into the official therapeutic protocol against COVID-19 in China. Qing Fei Pai Du Tang (QFPDT) is a Chinese multi-herbal formula newly developed and specifically optimized for the treatment of COVID-19. Therapeutic administration of QFPDT resulted in an improved cure rate in mild to critically-ill patients. However, the immunological mechanism for the efficacy of QFPDT has been poorly understood. Furthermore, the feasibility of prophylactic use in uninfected individuals remain unconfirmed. We thus examined whether the administration of QFPDT at a dose lower than recommended for therapeutic use alters hematological and/or immunological measures in healthy individuals. We found that QFPDT elevates the plasma levels of IL-1{beta}, IL-18, TNF-, and IL-8, which are key mediators of acute inflammatory responses to ssRNA viruses. No apparent adverse effects were observed during the trial. Our finding suggests that the pharmacological action of QFPDT is associated with the upregulation of a subset of proinflammatory cytokines despite its clinical benefits for COVID-19 patients. We should therefore be careful in its prophylactic use in uninfected individuals until we have a better understanding of the immunopharmacological action of QFPDT through further clinical studies with larger cohorts.