Echinacea as a Potential Force against Coronavirus Infections? A Mini-Review of Randomized Controlled Trials in Adults and Children

Abstract

Echinacea purpurea was shown to broadly inhibit coronaviruses and SARS-CoV-2 in vitro. This review discusses the available clinical evidence from randomized, blinded and controlled human studies. Two RCTs with results on enveloped viruses, respectively coronavirus infections during prevention treatment were detected. Incidence and/or viral loads were measured by RT-PCR and symptom severity was recorded. Jawad et al. (2012) collected nasopharyngeal swabs from adults (N=755) over 4 months of continuous prevention. Overall, 24 and 47 enveloped virus infections occurred, including 21 and 33 coronavirus detections [229E; HKU1; OC43] with Echinaforce extract [2400mg daily] and placebo, respectively (p=0.0114). Ogal et al. (2021) administered the same extract [1200mg] or control for 4 months to children (4-12 years) (N=203). Echinacea reduced the incidence of enveloped virus infections from 47 to 29 (p=0.0038) whereas 11 and 13 coronavirus detections [229E, OC43, NL63] were counted (p>0.05). Respiratory symptoms during coronavirus infections were significantly lower with area-under-curve AUC=75.8 (+/-50.24) versus 27.1 (+/-21.27) score points (p=0.0036). Importantly, viral loads in nasal secretions were significantly reduced by 98.5%, with Ct-values 31.1 [95% CI 26.3; 35.9] versus 25.0 [95% CI 20.5; 29.5] (p = 0.0479). Results from clinical studies confirm the antiviral activity found for Echinacea in vitro, embracing enveloped respiratory pathogens and therefore coronaviruses as well. Substantiating results from a new completed study seems to extrapolate these effects to the prevention of SARS-CoV-2 infection. As hypothesized, the testified broad antiviral activity of Echinacea extract appears to be inclusive for SARS-CoV-2.