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expert reaction to comments from the US acting homeland security under-secretary for science and technology, William Bryan, about the effects of sunlight, temperature, humidity and bleach on the coronavirus; and questions from Donald Trump about disinfectant and injections

At a White House press conference the US acting homeland security under-secretary for science and technology, William Bryan, made comments about the effects of sunlight, temperature, humidity and bleach on the coronavirus and survival on surfaces. There were also questions from President Donald Trump about disinfectant and injections.


Prof Paul Hunter, Professor in Medicine, UEA, said:

“That UV light inactivates SARS-CoV-2 is not surprising.  UV inactivates most viruses very efficiently.  Indeed UV disinfection is widely used for disinfection of drinking water.  Given the nature of coronaviruses we would expect them to be especially sensitive to disinfection by either hypochlorite (bleach) or UV light.  Any virus suspended in the air in sunlight would be expected to be inactivated pretty rapidly.  The same is true for any virus on surfaces exposed to sunlight or artificial UV irradiation.  The use of chlorine disinfectants such as household bleach on surfaces in rooms where patients are being nursed is already part of current advice.  It is true that any virus on surfaces in direct sunlight will be inactivated quite quickly.  But this is not new knowledge.

“However, these observations will have very little relevance to the control of COVID-19.  We know that COVID19 is mainly transmitted by droplet spread.  Most of those infected droplets will have either fallen onto the ground or other surface or been breathed in by another person before the UV disinfection takes effect.

“Any suggestion that UV could be used to treat this infection is just science fiction.  There is no way currently that UV could be used to irradiate inside the body that would do any good.  UV is also toxic to human cells.  Shining UV on people’s skin can cause burns and skin cancer, into peoples eyes it can cause conjunctivitis cataracts and blindness.  Even if we could shine it into people’s lungs it would also likely do immense harm and increase the risk of cancer.

“At a time when so much dangerous misinformation about COVID-19 is circulating some of which is likely to cost lives.  It is really important that our political leaders do not add to this death toll by making irresponsible statements that if acted upon could lead to serious harm and death.”


Prof Sally Bloomfield, Honorary Professor, London School of Hygiene and Tropical Medicine, and International Scientific Forum on Home Hygiene (, said:

“There is a considerable (although not exhaustive) database of publications which show that bleach can kill viruses on  surfaces – i.e. reduce them to a ‘safe’ non-infectious level, provided that it is used at a concentration of at least 1000ppm available chlorine, but preferably higher because it appears that coronaviruses have a very low ‘infectious dose’ (current estimates say it may be as little as around 200 virus particles).  Bleach is NOT suitable for internal use.”


Prof Kim Barrett, Distinguished Professor of Medicine, University of California, said:

“It would be disastrous to inject bleach or disinfectant into the body.  These are non-specific ways to kill living cells.  So they would not discriminate and would kill human cells too.  In fact, a major medical emergency occurs if people drink bleach.  It destroys cells that line the mouth, esophagus and stomach (basically by chemically burning them) and results in bleeding, chest pain, coma and potentially death.”


Dr Richard Parsons, Senior Lecturer in Biochemical Toxicology, King’s College London, said:

Would it be dangerous to inject disinfectant or bleach into the body?

“It would be incredibly dangerous.  Bleaches and disinfectants are designed to kill bacteria and viruses, using relatively crude and harsh chemical methods, so by definition they would also kill human cells.

What would likely happen to someone if they did inject disinfectant or bleach into the body?

“The effects would depend upon the amount and where it is injected, but any dose would be incredibly dangerous.  For a start, it would be incredibly painful.  Bleach is very alkaline, and would react with the components of the cells, such as proteins, which are essential for cells to work and would thus stop them from working.

“Detergents also contain anionic and non-anionic surfactants, which are designed to get rid of fats.  This would dissolve the fats that make the outer layers of the cells, breaking the cells apart and killing them.  At low doses, there would be significant death of the tissue surrounding the injection site, this is called necrosis.  If it is in the blood stream, the alkalinity of the bleach would change the delicately balanced pH of the blood, which would have serious repercussions for the function and survival of the red and white blood cells.  You would also get proteins in the blood coagulating, which could block the vessels.  It would also cause the internal walls of the blood vessels to be damaged, which would possibly make them burst and thus cause severe bruises to appear.  A high amount injected into the blood stream would have issues for areas far from the site of injection, as the blood would carry it around the body.  This could cause problems primarily with the heart, due to the muscle wall being killed off.  This could potentially cause a heart attack.  You would also damage your kidneys, as they filter the blood, and you could also suffer from brain damage, as the brain is the first port of call for blood coming from the heart due to its importance.

“Either way, it would be incredibly painful, most likely cause long-term organ and tissue damage, with the very high potential for fatality.  It would also have no therapeutic use whatsoever.  It is an incredibly dangerous thing to suggest, as people may feel that this is an option, especially when suggested by a government official.  We all have access to bleach and detergents at home as cleaning products.  Although hypodermics are not usually found in homes, some may drink the bleach thinking that this will protect them.  Also, the attacking of 5G masts because of the incorrect statements about them causing COVID infections and/or suppression of the immune system, thus making us more susceptible to infection, shows that people tend to listen to what is said in the media, no matter how scientifically incorrect it is.”


Prof Alastair Hay, Professor (Emeritus) of Environmental Toxicology, University of Leeds, said:

“There is a good reason why containers of disinfectant, and bleach in particular, warn about the danger of ingestion: the chemicals are dangerous.

“The hypochlorous acid in bleach burns all tissue with which it comes into contact and causes profound inflammation.  People who swallow bleach die horribly or are permanently scarred.

“Injections of bleach will not only destroy blood vessels but will impair the body’s natural defences.

“President Trump’s musings about injecting bleach are dangerous, so irresponsible, and a disgrace.  The president should be helping not hindering US doctors.”


Prof Atholl Johnston, Professor of Clinical Pharmacology, Queen Mary University of London, said:

“President Trump should read the label on his bottle of bleach.  The one I have in my hand says “do not ingest” along with many other dire warnings about getting on your skin or in your eyes.”


Prof Rob Chilcott, Professor of Toxicology, University of Hertfordshire, said:

Would it be dangerous to inject disinfectant or bleach into the body?  What would likely happen to someone if they did inject disinfectant or bleach into the body?

“Injecting bleach or disinfectant at the dose required to neutralise viruses in the circulating blood would likely result in significant, irreversible harm and probably a very unpleasant death.  It would not have much effect on viral particles within the cells and so, in that regard, would be rather pointless.  Such an act of stupidity would certainly qualify for a Darwin Award!”


Prof Crispin Halsall, Environmental Chemist, Lancaster University, said:

“I suspect Mr Bryan (acting Homeland Security Undersecretary) was referring to the work of scientists that examined the effects of solar UV light and higher temperatures on deactivating the virus present on environmental surfaces (not the human body!).  It is vital that the general public DO NOT interpret this news as a green light to wash with, ingest or inject detergent or bleach, or expose themselves to harmful UV radiation.”


Dr Penny Ward, Visiting Professor in pharmaceutical medicine at Kings College London and the Chair of the Education and Standards Committee of the Faculty of Pharmaceutical Medicine, said:

“UV irradiation and high heat are known to kill virus particles on surfaces and coronavirus particles are no exception to this general rule.  Similarly evidence shows that bleach in an appropriate concentration will also clear viruses and bacterial contamination of surfaces.  These principles are applied for cleaning of contaminated rooms, and to maintain hygiene and prevent fomite transmission of infection in public areas.  Neither sitting in the sun, nor heating will kill a virus replicating in an individual patients internal organs.  Drinking bleach kills.  Injecting bleach kills faster.  Don’t do either!”


Dr Wayne Carter, Associate Professor (Toxicology Lead), School of Medicine, University of Nottingham, said:

“Disinfectants and bleach are strong oxidising agents, useful to kill bacteria or viruses when they are deposited on surfaces, but these agents should not be ingested or injected.  These agents can cause severe tissue burns and blood vessel damage.  As with other potentially poisonous agents, it is the dose (amount taken into the body) that makes the poison, but ultimately, under no circumstances should members of the public ingest or inject disinfectants or bleach.”


Prof Graham McGeown, Reader in Physiology, Queen’s University Belfast, said:

“The experiments that were carried out were looking at how the virus can best be killed on surfaces and materials, presumably with a view to reduce spread via indirect contact.  These results cannot, and were never intended to be applied to the problem of treating the virus in humans.  Bleach is toxic to human cells and would damage any tissues they come in contact with if it were injected.  Swallowing bleach can be fatal.  Even strong UV light is potentially harmful and could cause burns and potentially result in cancer if shone on the skin, just as sunburn does.  So, while bleach and UV may help to kill viruses on objects around us, they are much too toxic to inject or apply directly as a treatment in humans.”


Commenting on the remarks from Trump about disinfectant and injections:

Prof Parastou Donyai, Director of Pharmacy Practice and Professor of Social and Cognitive Pharmacy, University of Reading, said:

“Medicines or poisons taken by people start their effect on the body at different speeds, depending on how they are taken.  For example, ordinary tablets go into the stomach first before being taken into the rest of the body and this slows down their effect.  The quickest way to get something into the body is by injecting it.  Sadly, this gives very little time to step in and reverse the injection of a poison.  We have already seen people mistakenly poisoning themselves by taking chloroquine when their hopes were raised by unscientific comments.

“What is shocking about these latest comments is that they completely bypass other important facts about injections too: not only will home-made injections bruise, burn, or block the veins, they will almost certainly also introduce new infections straight into the body, the very thing people are desperate to avoid.  People worried about the Coronavirus or COVID-19 should seek help from a qualified doctor or pharmacist, and not take unfounded and off-the-cuff comments as actual advice.”



All our previous output on this subject can be seen at this weblink:


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