A virus-killing chemical found in insect repellent can also destroy the infection that causes Covid-19, scientists have claimed.
Citriodiol, an ingredient in Mosi-guard and other ‘bug sprays’, was shown to damage the coronavirus in government-run research.
The Defence Science and Technology Laboratory (DSTL) conducted the research on chemical under orders of the British Army.
Early findings claimed Mosi-guard’s natural spray started to attack the coronavirus in just one minute.
It suggests citriodiol has promise against SARS-CoV-2 — the virus that causes Covid-19, having previously shown to work on other similar coronaviruses.
However, experts warned it is still early days, and the chemical has not been shown to prevent people from catching the coronavirus.
Products containing citriodiol can be purchased online at outlets such as Amazon for around £10 ($13) but stocks appear to be low.
Citriodiol found in Mosi-guard among other ‘bug sprays’, has shown to damage the coronavirus in government-run laboratories
Military scientists started trials on citriodiol in February at Porton Down, government run laboratories in Salisbury, Wiltshire.
The DSTL — a branch of the Ministry of Defence — was tasked with the research by the Surgeon General, the most senior medical officer in the British Army.
British armed forces were given the insect repellent as an extra layer of protection against the virus at the start of the pandemic — even though there was no proof it worked, Sky News first reported.
DSTL wanted to determine the level of anti-viral activity of Mosi-guard’s natural spray against the coronavirus.
Preliminary findings published today suggest it ‘can kill the strain of coronavirus that causes Covid-19’, Defence Minister Jeremy Quin said.
What is citriodiol, in which products is it found and how could it combat coronavirus?
Citriodiol is chemical which actively repels insects.
It has long been widely used in commercial repellents.
The chemical is used in the following products:
- Care Plus Natural Insect Repellent
Citriodiol comes from the leaves of the eucalyptus citriodora tree, native to Asia, South America and Africa.
Previous studies have found the chemical is also able to kill the SARS virus, which caused a pandemic almost 20 years ago.
It remains unknown if the chemical is able to destroy SARS-CoV-2, the virus which leads to COVID-19, but the two viruses are closely related.
Deet, another common chemical used to keep bugs away, is not believed to be effective against coronavirus.
Mosi-guard, the commercial product that contains citriodiol, is not available at Boots or Superdrug but can be bought online.
The company which manufactures the product in the UK, Citrefine International Ltd, based in Leeds, is calling on the Government to test the product and see is it is effective.
The Ministry of Defence is believed to be undergoing tests to determine just that.
Two experiments took place, to assess if the chemical kills the virus when applied to it directly as a liquid, as well as on latex ‘synthetic skin’.
After one minute, tests showed a liquid drop of Mosi-guard’s natural spray reduced quantities of the SARS-CoV-2, with a higher dose ‘resulting in no recoverable virus’.
This suggests it has ‘anti viral properties’, the report published on the government’s website says.
‘Additionally, viral studies on latex indicated that Mosi-guard Natural had anti-viral activity against SARS-CoV-2 England-2 isolate,’ it said.
The England isolate refers to the fact the virus particles were taken from an English patient, therefore it is not clear if it would work against strains found in other parts of the globe.
It took longer for the virus to die out on the fake skin than on surfaces, taking four hours for levels to drop enough to be noticed.
Even though SARS-CoV-2 was slowly killed off, it was still detectable from all surfaces tested in the fake skin experiments.
Defence Minister Jeremy Quin said: ‘DSTL’s latest research shows that sprays containing citriodiol, which have been made available to MOD units engaged in the Covid response, can kill the virus.
‘We are sharing our preliminary findings today so others can take forward additional research to confirm and expand on our findings.’
‘Defence has played a wide variety of roles in supporting efforts to tackle coronavirus. We are pleased that this is another example of Defence sourcing innovative ways to keep people safe.’
Dr Matthew Lloyd, a senior lecturer, Department of Pharmacy and Pharmacology at University of Bath, said there is ‘definitely an effect’ of Mosi-guard to a ‘very high’ significance.
He told MailOnline: ‘Looking at the kill tests viral load is been reduced by 100-1000 times. On artificial skin, after four hours, viral loads are only reduced by 10-fold. So the effect is quite small.’
However, he added: ‘The insect repellent formulation also contains ethanol and isopropanol (short-chain alcohols) and these are probably equally effective. As far as I can see they did not actually do a statistical significance test of the alcohols vs. the insect repellent, but they look equally active to me.
‘My feeling is that we need to be cautious as it may be the alcohol carrier rather than the citriodiol killing the virus in the Mosi-guard.
‘One advantage might be that citriodiol would be quite a lot less volatile than ethanol or isopropanol which would make probably it easier to apply. It would probably be an acceptable substitute in the field for using soap and water. It is probably of similar effectiveness.’
Citrefine International Ltd, the company that produces citriodiol, also believed it could offer protection against the coronavirus, but had not carried out its own research.
Jacqueline Watson, managing director the company, said in April she would like the government to support a formal testing programme.
‘What we can say is that we do feel there is a very good chance it could work against this virus but it does of course need to be thoroughly tested,’ she said at the time.
Bug sprays nearly always contain DEET — a chemical that when applied to the skin or clothing provides protection against various insects.
But the laboratory work did not look at DEET and so it is unclear what role this would play.
Even if citriodiol is able to zap the virus in some way, as the reports claim, it is not clear if this prevents people from getting infected.
British troops were given stocks of Mosi-guard early in the pandemic on suspicion it could have an effect on the strain of the disease behind the pandemic.
Preliminary tests have shown that low concentrations of citriodiol can be effective in killing SARS CoV-1, a coronavirus closely related to the one causing the pandemic.
SARS, originally found in China, caused epidemics in 2002 and 2004, predominantly in Asia. But no cases have been detected since.
Secretary of State for Defence Ben Wallace said a citriodiol-based spray has been given to personnel in light of the Surgeon General’s advice it wouldn’t do any harm.
The MP said it should be used on a precautionary basis as against exposure to the virus.
An Ministry of Defence spokesperson told MailOnline at the time: ‘Citriodiol is known to have anti-viral properties and has been used as a barrier against the SARS 1 virus.
‘Its utility for protecting against COVID-19 is therefore being explored by the Ministry of Defence as an additional protective measure for personnel working on the response.
‘Further work is required to determine its full effectiveness, acquisition and distribution.’
But some politicians have expressed concern at the trials. In separate letters, politicians asked Defence Secretary Ben Wallace for more details and clarification.
Chief among their concerns are why, with such little evidence, are resources being diverted to this endeavour.
Stewart McDonald of the Scottish National Party asked to see the evidence that informed the MoD’s decision.
The letter states: ‘If this is based on science, it is vital that the evidence is made public and all frontline workers are given the same advice.
‘If there is no evidence that it will be effective, then the MoD must explain why this product is being issued, creating a false sense of security and putting lives at risk.
‘Clarity on this matter is of the greatest urgency.’
Jamie Stone of the Liberal Democrats wrote in his letter: ‘The over-riding point is that if your decision has been taken on the basis of sound scientific evidence, then why are other frontline workers not also being provided with citriodiol?’
Citriodiol comes from the oil of the Eucalyptus citriodora tree, making it a naturally sourced ingredient.
It has already passed rigorous safety and efficacy tests, making it an attractive avenue for Covid-19 protection.
However, there is currently no proven vaccine, chemical or drug that prevents Covid-19, although work is ongoing.
The advice from the World Health Organisation (WHO) on avoiding infection is still to clean your hands frequently and thoroughly, keep at least one metre distance from others and catch sneezes and coughs in a tissue or your elbow.