Echinacea purpurea broadly inhibits coronaviruses and SARS-CoV-2 in vitro [1]. This review discusses the available evidence from human studies. A literature search
on PubMed and EMBASE yielded two RCTs with results on coronavirus infections during
prevention with Echinacea purpurea. Incidence and viral loads were measured by reversed transcriptase polymerase chain
reaction (RT-PCR). Jawad (2012) collected nasopharyngeal swabs from N=755 adults over
4 months of prevention. Overall, 24 and 47 enveloped virus infections occurred, including
21 and 33 coronavirus detections [229E; HKU1; OC43] with Echinaforce [2’400mg daily]
and placebo, respectively (p=0.0114). No significant difference was observed on symptom
level. Ogal (2021) administered Echinaforce extract [1’200mg] or control for 4 months
to N=203 children (4 – 12 years). Echinacea reduced the incidence from 47 to 29 enveloped
virus infections (p=0.0038) and 11/13 coronavirus detections [229E, OC43, NL63] were
counted (p>0.05). Viral loads in nasal secretions were significantly diminished 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).
Finally, respiratory symptoms during coronavirus infections were significantly reduced
with area-under-curve AUC=75.8 (+/-50.24) versus 21.1 (+/-21.27) score points (p=0.0036).
Echinacea’s broad antiviral spectrum was confirmed in two clinical trials suggesting
its potential for prevention of infections by respiratory pathogens, including coronavirus
[2]
[3].
