This clinical trial investigates the preventive and therapeutic effect of Echinacea purpurea (coneflower) in viral respiratory infections, in particular SARS-CoV-2 (COVID-19). 120 healthy adults (18-75 years) were randomized to receive either echinacea supplementation(2,400 mg daily) or no intervention. For acute respiratory symptoms, the dose was increased to 4,000 mg/day for up to ten days.
The results show that the echinacea group had a significantly lower rate of respiratory tract infections. In the prevention phase, 21 infections occurred in the echinacea group compared to 29 in the control group. For SARS-CoV-2 in particular, the risk was reduced by 63 % (p = 0.03). During acute infections, echinacea treatment reduced the viral load by an average of 99 % and shortened the duration of the illness by up to 8 days.
Conclusion: Echinacea purpurea could be an effective supplement for the prevention and treatment of viral respiratory infections, especially against SARS-CoV-2. Further studies are needed to confirm its long-term efficacy.
Background:
Viral respiratory infections are one of the most common causes of illness worldwide. The COVID-19 pandemic has raised awareness of the need for effective prevention strategies. While vaccines can prevent severe cases, their protective effect against infection and transmission decreases over time. There is therefore a need for additional antiviral substances. Echinacea purpurea has been shown to have in vitro antiviral effects against various coronaviruses, including SARS-CoV-2. This study investigates the potential protective and therapeutic effects of Echinacea against COVID-19.
Methodology:
- Study design: Randomized, open, controlled, exploratory clinical trial.
- Participants: 120 healthy adults (18-75 years).
Intervention:
- Prevention: 2,400 mg Echinacea purpurea daily over three cycles (2 months each, with one-week breaks).
- Therapy: For acute symptoms 4,000 mg/day for up to ten days.
Measurement methods:
- Monthly PCR tests and blood samples for the detection of respiratory viruses, including SARS-CoV-2.
- Recording of symptoms by means of a diary.
- Evaluation of the viral load by RT-qPCR.
Results:
Reduction in the frequency of infection:
- Overall, fewer viral infections occurred in the echinacea group(21 vs. 29 in the control group).
- The rate of SARS-CoV-2 infections was significantly lower in the echinacea group(5 vs. 14; p = 0.03), which corresponds to a risk reduction of 63 %.
Fewer symptomatic infections:
- There were 10 symptomatic episodes in the echinacea group compared with 14 in the control group.
- Of these cases, 5 and 8 respectively were COVID-19 infections.
Reduction of the viral load:
- During an acute infection, echinacea reduced the viral load by more than 99 % (p < 0.05).
- The mean time to virus freedom (qPCR-negative) was reduced by 8.0 days for all viruses and by 4.8 days specifically for SARS-CoV-2.
Reduction in the duration of illness and fever phases:
- The number of fever days was significantly reduced in the echinacea group(1 day vs. 11 days in the control group, p = 0.003).
- However, the overall intensity of the symptoms was not significantly different.
Safety and compatibility:
- No serious side effects occurred.
- Two hospitalizations due to COVID-19 occurred in the control group, but none in the echinacea group.
Discussion:
The study provides the first clinical evidence for the antiviral properties of Echinacea purpurea against SARS-CoV-2. The results suggest that Echinacea can be used both preventively and therapeutically against respiratory infections. The antiviral effect could be explained by several mechanisms:
- Direct antiviral activity: In vitro studies show that echinacea can inhibit viral replication.
- Immunomodulation: Echinacea promotes a balanced immune response by inhibiting pro-inflammatory cytokines such as TNF-α and IL-1β and increasing IL-10.
- Reduction of the viral load: Faster elimination of the virus could reduce the risk of further transmission.
Although the study shows a significant reduction in SARS-CoV-2 infections, some limitations should be noted:
- The number of participants is relatively small, so that larger studies are necessary to confirm the results. The open study designs do not allow complete elimination of bias.
- The effect on long-term consequences of COVID-19 has not been investigated.
Conclusion:
This study shows that long-term echinacea supplementation can reduce the risk of SARS-CoV-2 infection and shorten the duration of illness in acute infection. Due to its broad antiviral and immunomodulatory effects, Echinacea purpurea could be a valuable addition to existing prevention and treatment strategies. Further randomized, placebo-controlled trials are needed to determine the long-term effects and optimal dosages.