Study adds credibility of antiviral effects of echinacea extract in relation to Covid-19

By Nicola Gordon-Seymour

- Last updated on GMT

Echinacea purpurea or Purple Coneflower is a herb traditionally used to support the immune system.   Image © ChristopherBernard / Getty Images
Echinacea purpurea or Purple Coneflower is a herb traditionally used to support the immune system. Image © ChristopherBernard / Getty Images

Related tags Echinacea Herbal supplements Echinaforce COVID-19 Respiratory tract infections

A standardised extract of Echinacea purpurea is an efficient and cost-effective antiviral counter measure to vaccination in the prevention of respiratory tract infections (RTIs) and for reducing concomitant viral loads, say scientists.

Five months of supplementation with 2,400 mg per day of Echinaforce (A.Vogel AG, Switzerland) resulted in a 25% reduction of all respiratory virus, increasing to 43% for enveloped viruses and 48% for coronavirus infections in subjects, according to data published in Frontiers in Pharmacology​.

A 99% reduction in viral loads when 4,000 mg of EF was administered during acute RTI episodes, which suggests the limited ability of respiratory viruses to evade the antiviral effects attributed to EF extract, wrote the researchers.

“A commercial preparation of Echinacea purpurea in the licensed dosage (Echinaforce extract), represents a safe, easy-to-use and widely available cost-efficient antiviral with effects in preventing respiratory tract infections, including SARS-CoV2 and reducing virus load,” ​they stated.

“It may add well to existing counter measures in the current Covid-19 pandemic like vaccinations, social distancing and wearing protective facemasks. Future confirmatory studies are warranted.”

The study was funded by A.Vogel AG.

Further substantiation for the inherent preventative qualities of the herb

Commenting independently on the study’ findings, Dr Stefan Gafner, Chief Science Officer at the American Botanical Council, said that preventative studies can be difficult to interpret and limitations in the current trial necessitate further testimony. All the same, results conform with previous findings and further substantial the inherent preventative qualities of the herb, he said.

“I hope manufacturers may take a closer look at echinacea as an ingredient, and possibly invest more resources into clinical studies, which may lead to more confidence by consumers about the benefits of their product and therefore increased sales​.”  

Additional options            

Novel pathogens, like Covid-19, present a significant threat to public health, with vaccines often the first line of defence. Messenger RNA and vector-based vaccines were credited with 90% effectiveness in preventing infections, progression to severe illness, and transmission of SARS-CoV-2.

However, recent US data demonstrates the short-term potency of Covid vaccines and identified a sharp decline in efficacity after eight months, along with marked differences between vaccine variants, the authors stated.

“Additional options are urgently needed to effectively attenuate non-severe infections and naso-oropharyngeal virus concentrations in order to further contain viral dissemination,”​ they said.

Echinacea exhibits broad antiviral effects, including for coronaviruses in both adults and children, and particularly formulations containing fresh Echinacea purpurea​ that reduces inflammatory cytokines while increasing anti-inflammatory cytokines that respond to invading pathogens.

Three-cycle design

The study took place during the Covid-19 pandemic to investigate the antiviral effects of EF on 120 healthy volunteers.

Subjects endured three prevention cycles (two lasting two months and the third one month) and were treated with 2,400mg of EF extract daily. Tablets contained 400mg of an hydroethanolic extract of Echinacea purpurea​ (95% external plant and 5% root).

All volunteers were Caucasian with a mean age of 36 years. None had been vaccinated against Covid-19 at study baseline; three received a first SARS-CoV-2 dose towards the end the first phase, and 12 had completed the vaccine programme by the study end.

Subjects had to provide naso/orophyaryngeal (NP/OP) swaps and blood samples on a monthly basis - and on days one, two, five and 10 during acute symptomatic episodes - for virus detection and quantification, and also completed a symptom diary to establish severity of respiratory symptoms.

Samples identified 21 and 29 positive cases of any virus in the EF and control group, of which five and 14 samples tested SARS-CoV2 positive.

Acute RTI episodes were treated with 800mg EF extract (4,000 mg/day) five times daily, for up to 10 days. The control group was observed in parallel for the same period.

Strong risk reductions

EF treatment during acute episodes significantly reduced overall virus load and the time to clearance for all viruses (eight days) and SARS-CoV-2 (just under five days), relative to baseline. The number of fever days also reduced but not overall symptom severity, and there were fewer hospitalisations in the intervention group.

Both groups took other medications during RTI episodes, but instances were higher among the control group, which the researchers say may have masked the effects of EF treatment on symptom level.

The strongest risk reductions for RTI (63%) were associated with SARS-CoV2 viruses, although the authors warn against over interpretation as clinical significance “was only attained for the prevention of coronaviruses, and for SARS-CoV-2​”.

We did not monitor the use of non-pharmaceutical interventions (NPIs) during the study and the impact of this potential confounder remains questionable​,” they wrote.


Findings add further credibility to the antiviral effects of EF in preventing RTI viruses, including SARS-CoV2, said the researchers.

“Immune modulation instead of immune-stimulation can allow, if necessary, a prolonged preventive use of this extract, to exploit its potential ability to reduce viral loads.”

Furthermore, by substantially reducing virus loads in infected subjects, ​EF offers “a supportive addition to existing mandated treatments like vaccinations​”.

Source: Frontiers of Pharmacology
Published online April 26, 2022: doi: 10.3389/fphar.2022.856410 ​ 
‘Echinacea Purpurea For the Long-Term Prevention of Viral Respiratory Tract Infections During Covid-19 Pandemic: A Randomized, Open, Controlled, Exploratory Clinical Study’
Authors: E. Kolev, et al.

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