Was anyone really surprised that Mr Trump caught COVID-19? Were you surprised that a large number of people who attended his rally to appoint a new Supreme Court justice also caught the disease? If you have been reading these articles, you will not be.
As you may have realised, I have a professional interest in the transmission of diseases by airborne particles, what was once called miasma but which now is understood to include both microbes and inanimate matter. In the field of industrial disease, biologists, physicists and chemists have for over a century worked with physicians and pathologists to understand the methods of transmission of coal, asbestos, silica and even farmyard and domestic dusts. More recently, we have turned our attention to nanoparticles (particles measured in thousand millionths of a metre, the size of a virus) in relation to the apparent consequences of inhaling polluted air. This is the hard physical and chemical science that has been under-stressed by both politicians and media, as well as by their scientific advisors, when discussing COVID-19.
What we have heard a great deal about is 'The Science' and following it, and we are all now familiar with epidemiological data as presented at news conferences. Epidemiology is the science of describing the patterns of health and illness in populations and drawing conclusions from them by inductive reasoning. This then allows predictions to be made by mathematical modelling as to what might happen in light of different approaches to management. All such predictions are surrounded by uncertainty. This is what might be regarded as soft science, useful for testing hypotheses and for proposing new ones. It has been the dominant basis of our response to the pandemic, but it is not easily testable experimentally. The reliability of the predictions can only be tested by seeing the consequences, and then only very approximately.
For example, how would you find out whether closing pubs at 10pm has worked? A moment's thought will tell you that any changes in infection rates following this action could be a consequence of many different associated behaviour patterns in the owners and customers affected by the rule.
Epidemiology has another very significant weakness. Save in exceptional circumstances, it provides very little information on the dose of the particles which you require to receive before falling ill, yet dose is fundamental to understanding how particles cause disease. The study of the dose of dangerous substances, poisons, is called toxicology, and a principle of toxicology is that the higher the dose, the greater the risk. It is particularly difficult to measure doses of microorganisms in epidemiology, yet this is important to understanding the spread of infections. In spite of the apparent dominance of epidemiology in the media account of COVID-19, much of the advice given has been based on the harder science, yet this has hardly been discussed. I believe it would be more helpful for people in terms of understanding what we are asked to do if this science were made clearer.
So here I go again; some hard scientific facts:
• SARS-CoV-2 is about 100 nanometers in diameter and is exhaled in droplets of water. It will therefore remain suspended in air according to physical laws, depending primarily on particle diameter, for from a few seconds to many hours. The smallest fall very slowly indeed.
• If exhaled into still air in a room or average bar, many virus particles will remain suspended and available for you to inhale as long as you remain there. The longer you remain, the more you will inhale, and being a few feet from the infected person will give little protection.
• If you are infected with SARS-CoV-2, you start to exhale viruses before you get symptoms. This was not known before this pandemic and does not apply to all viruses. It is one reason why this one is so infective.
• The amount of air you exhale rises with increasing rate and depth of breathing, so loud talking, coughing, singing, and exerting yourself causes more viral particles to be exhaled if you are infected. Equally obviously, the more infected people in a space, the more virus is floating around; the poorer the ventilation of the space, the greater the virus concentration in it. These facts tell you why pubs, small restaurants and busy shops are particularly dangerous, but also what measures are necessary to reduce these risks. Reduce numbers and increase ventilation to reduce risks. Noisy places cause loud talking, so reduce noise levels.
• The science behind masks is very well understood. To protect you completely from virus-sized particles they need to fit your face closely all round and be of special quality. These are used by staff in intensive care. Medical quality masks that do not fit perfectly or are worn over a beard give a measure of protection but are most useful to protect others from you if you are harbouring the virus. The face coverings that most of us wear are not efficient filters of viruses but do catch the larger liquid droplets and are known to reduce spread of infection if worn by a high proportion of people. You can see and test your mask's effect on droplets on a cold frosty morning.
• This virus is known to survive for up to a few days on surfaces, the duration depending on the material. How relevant this is to transmitting infection is not known but in terms of dose is likely to be less important than airborne spread. However, some diseases such as childbirth fever have been known for more than 200 years to be transmitted by personal contact and there is biological evidence that SARS-CoV-2 can be transmitted in this way, hence the importance of hand and face contact and frequent vigorous handwashing.
If you understand these simple scientific facts, you don't need rules, laws and fines. You can protect both yourself and others. Just as mosquitoes spread malaria, other people (and maybe you) spread the disease COVID-19. You don't need to ask what the epidemiology predicts; when someone tells you that a place is safe or dangerous, you can see for yourself and make your own risk assessment before venturing in. Just remember, anyone can be a spreader, your boyfriend, your daughter, your neighbour. The more people you spend time talking to, the more likely you are to catch the virus. Act accordingly. But there is one other thing.
What epidemiology does tell us, and it is doing this very well indeed, is the overall risk as opposed to the likely increase in risk in specific places, and how that risk is changing. The overall risk relates to the numbers of people infected in the area you live in. In general, you can be guided by Public Health Scotland
figures which vary around the country and are increasing, but show one to two per 1,000 found per week in all areas with positive swabs. This is why it is so important for politicians to regulate the numbers of people meeting together indoors. As those detected may well have infected others already, you may reasonably assume that the number with positive tests seriously underestimates the numbers infected, so for an instant risk assessment in a city in Scotland there may now be about a one in 100 chance that the person you are talking to is infected. If the room or shop you enter has 10 people in it, there is a one in 10 chance that one is infected.
I think you will agree that this is all both easy to understand and alarming. Why then did Mr Johnson initially, and Mr Trump persistently, not understand it? My heart sank when the former encouraged us all to go back to bars and cafes; it was so obviously the wrong thing to do at the time, but it took him an age to see the light. As for the extraordinary Mr Trump, it appears that he is so severely narcissistic that he believed himself invincible even to viruses and cared little for the safety of his electorate. Now it appears that much (though not all) of the Republican hierarchy is afflicted with the same personality disorder as well as by COVID-19.
It is too early to comment on the very important matter of Mr Trump's recovery other than to note that it will be some weeks before we shall know. His unusual behaviour and apparent euphoria as I write is commonly seen as a side effect of high-dose steroids, which he is known to be taking, and may give a misleading indication of his response to the infection. We must hope that he will make a full recovery. Many Americans must be contrasting the care he is receiving with that of the hundreds of thousands who have died from this disease in the USA and thinking of the situation generally in that country of those who are unable to access decent healthcare, such as diabetic and asthma medications. Perhaps they will notice that our Prime Minister was treated in the NHS. They may be thinking of Trump's attitude to Obamacare and wishing they could have a bit of Trump's care.
As the tides of the pandemic have ebbed and flowed, we have learnt a lot about this new virus and there are fewer excuses now for political mistakes. It is apparent that since its initial decline it has come back vigorously, as was expected when students went back to universities and colleges. This occurs locally and could be controlled locally if track and trace is quick and efficient and if people isolate.
Return to education by people of student age is essential. Opening of shops and restaurants is essential to the economy and is being controlled fairly effectively so far by regulation of distancing, masks and numbers. Outdoor work is generally safe if workers distance themselves and many office workers can work from home.
It has become apparent that local outbreaks are the source of most infections in UK now, often associated with multiple household contacts or superspreading events when many become infected simultaneously. While these latter events may be associated with a highly infective individual, I suspect that most are simply due to many people sharing the same space with several infected individuals who are not taking precautions. While a drunken pub crawl is an obvious example, the recent White House event is a more telling one and is likely to have very widespread and serious consequences. It was clearly due to failure to believe that the virus can infect anyone, even the wealthy and privileged. Have they learnt this lesson? I hope so.
Anthony Seaton is Emeritus Professor of Environmental and Occupational Medicine at Aberdeen University and Senior Consultant to the Edinburgh Institute of Occupational Medicine. The views expressed are his own