CBD — the trendy cannabis-derived supplement — may help fight off a Covid infection, a lab study suggests.
A team of researchers from the University of Chicago found it was able to neutralise the virus and prevent it from multiplying.
The study was done in mice and in human lung cells — so the scientists say there are no guarantees it will work in the real world.
But they are calling for human clinical trials to explore cannabidiol’s potential anti-Covid properties.
Throughout the pandemic, a number of medications have showed promise in lab studies but have had mixed success in real world trials – including hydroxychloroquine and remdesivir.
The Chicago team also used medical-grade CBD and warned people against self-medicating with off-the-shelf products, which are often low purity.
They found that exposing human lung cells to CBD for two hours before Covid greatly inhibited the virus’s ability to replicate for up to six hours.
A team of researchers found CBD. a compound found in cannabis, was able to slash the ability of Covid to replicate in human cells. In this chart the effectiveness of various compounds found in cannabis is plotted by the percentage of Covid spike proteins found in sampled cells. The further right on the graph the point is the higher the concentration, and the lower, the less virus spike proteins were found in the cells. Of particular note is a combination of CBD and THC, which is the psychoactive part of cannabis, actually reduced the effectiveness compared to pure CBD
The researchers also tested CBD’s effectiveness against a number of Covid variants and proved to work against all those tested. Variants tested included the original strain (black), the Beta variant (orange), Alpha (blue), and gamma (green)
Lead author of the study Professor Marsha Rosner, said the team now want to conduct human trials to test CBD effectiveness against Covid in the real world
The team then replicated their findings in two other types of human cells and tested the original Wuhan version of the virus, as well as the Alpha, Beta, and Gamma Covid variants.
What is CBD oil?
Cannabidiol (CBD) is a chemical found in cannabis that has medical benefits.
It can be prescribed by the NHS for a small list of conditions, including severe epilepsy, vomiting caused by chemotherapy and multiple sclerosis.
The NHS version cannot get you high, because it doesn’t contain tetrahydrocannabinol (THC) – the chemical in cannabis that has that effect.
But the health service warns that most of the cannabis-based products that can be bought online will be illegal and may contain THC.
And health shops selling CBD products only contain very small amounts of the chemical, so it is unclear what effect it has.
The risks of using cannabis products containing THC include psychosis and drug dependency.
Its side effects include reduced appetite, diarrhoea and feeling sick.
The new Omicron variant, which has been responsible for a surge in Covid cases in both the UK and the US, was not tested in the study. Neither was the Delta version of the virus.
Lead author of the study, Professor Marsha Rosner, said the result completely unexpected.
‘We just wanted to know if CBD would affect the immune system,’ she said.’
‘No one in their right mind would have ever thought that it blocked viral replication, but that’s what it did.’
The researchers, who published their findings in Science Advances originally set out to explore if CBD’s anti-inflammatory properties could help people recover from the aftermath of Covid infection before they found the surprising result.
Further tests on mice found pretreating the rodents with CBD one week prior to exposure to Covid suppressed infection in both the lungs and nasal passages of the animals.
Professor Rosner said: ‘These results provide major support for a clinical trial of CBD in humans, she said.
She added that, if proven effective, she would envision CBD forming a prophylactic treatment for Covid, something a person would take if they had been exposed to the virus in an attempt to reduce the chances of becoming ill.
Inspired to explore further, the team also found that people taking CBD medication designed to help prevent epilepsy had less chance of catching Covid than the rest of population.
Analysing real-word data taken from a national US survey, they found a cohort of 1,200 patients taking an oral CBD medication for epilepsy had less chance of catching Covid compared to their non-medicated equivalents.
However the authors have insisted that CBD does not take the replace vaccination as the ‘first line of defence’ against Covid and have urged the public to keep following the advice of public health authorities.
Professor Rosner added that the observed effect in the studies was only for high purity CBD, generally only available as a prescribed medication.
‘Going to your corner bakery and buying some CBD muffins or gummy bears probably won’t do anything,’ she said.
In a further blow to anyone thinking of smoking marijuana in an attempt to fight off Covid, the team also found THC, the part of the cannabis plant which has psychoactive properties, actually reduced CBD’s effectiveness against the virus.
Professor Rosner said the team was excited about the potential of CBD to help against the Covid pandemic, but added more research needed to be done.
CBD is product which has been championed by the health conscious and studies have shown it can help reduce anxiety and relieve pain.
However, CBD product some manufacturers have come under fire for claiming the cannabis compound is a panacea that can help cure diseases such as cancer and Alzheimer’s.