(Updated March 23, 2020)

In the aviation/occupational community we are suddenly awakening to a new reality which is our world in a pandemic. I am being asked many questions about this, as are most physicians, and so I have prepared this summary, which I will edit on a real-time basis as new data become available. All of this information is available online, but I find too often it is buried in a jumble of chaff and misinformation. And the reality is that people trust their own physicians to filter out the garbage and give them honest truths. At the end of the document I started a chain of FAQs – the things I’m asked most – so that might help you.

First – some basics

What is a virus? Viruses are little bundles of RNA or DNA – the computer code of life. They are not alive – and this confuses some people. Viruses can’t reproduce, move, eat or anything else we associate with “alive”. They need a living cell to do all those things – and your cells will do quite nicely. The virus enters your body in its preferred manner (usually through mouth, nose or eyes – but they can get in other ways – eg. sexually transmitted viruses). It then unpacks itself, injects the malicious DNA or RNA code into your cell, hijacking the cell and telling the cell to make more copies of itself. We have an entire immune system designed to defend against these hijackers. If your immune system recognizes the invader as foreign – it generates an inflammatory response – sort of like pulling a fire alarm. Specialized killer cells flood into the area of invasion and kill the virus. Then a record is made of what the virus looked like (immunity) so it can be rapidly killed if it shows up again. Epidemics happen if a population has never “seen” a virus before – everyone is susceptible – and the virus travels from person to person. When many of us have “seen” it – by being previously infected, or immunized, epidemics aren’t possible because there’s not enough vulnerable people to sustain the forest fire (termed “herd immunity”).

Because they’re not alive, viruses are both easy and hard to kill. Easy – because the DNA or RNA is wrapped in a protein layer like a baggie – and disrupting this is relatively easy – bleach, alcohol, detergents – lots of things will do it . And because they have no cell to protect them things like UV light, heat or cold can also kill them. But hard to eradicate – viruses have been found in permafrost graves of explorers from hundreds of years ago that were still capable of reactivation and infection.

Viruses are small – very small. They range from .06 microns to .14 microns. Thus they float in the air without difficulty because they weigh almost nothing (a study in New England Journal of Medicine, March 17, 2020 found coronavirus blown into the air can stay airborne up to 3 hours. Most droplets however fall right away. For this reason the virus is NOT considered airborne). Here are some size comparisons:

Particle sizes

This is why masks don’t protect well people against viral illness – not only do even good quality surgical masks let 20% of particles of viral size through – the mask is not sealed to your face – so particles just effortlessly flow around it. And they don’t protect your eyes. Hence the WHO advises not to use them if you’re not sick.

What is corona virus? Better question – what ARE coronaviruses – they’re a family. Corona viruses have been around a long time. There are 6 types that infect humans – and four of these cause about a third of what we refer to as “the common cold”. Another half of colds are caused by rhinoviruses. The final 20% of colds are caused by an assortment of 200 different viruses. So what makes this virus so bad? One thing viruses love to do is hop species – and when they do they often undergo mutation (remember “swine flu – started in pigs, hopped to humans or 2002’s SARS originating in civets?). This current coronavirus is called SARS-CoV-2 – named for “Severe Acute Respiratory Syndrome, coronavirus number 2”. We think based on genetic analysis it originated in bats (there’s some commonality with Pangolins at 93%, suggesting it may have passed through them – but bat sourced virus is an almost 98% genetic fit). The virus mutated and emerged in an outbreak in Hunan, China, centered on a seafood market there that also sold live animals. We haven’t proved an animal source but it seems likely.

What makes this one so bad is its outer shell. Like other coronaviruses, SARS-CoV-2 has four structural proteins, known as the S (spike), E (envelope), M (membrane), and N (nucleocapsid) proteins; the N protein holds the RNA genome, and the S, E, and M proteins together create the viral envelope. The spike protein is the protein responsible for allowing the virus to attach to the membrane of a host cell. The virus information is carried in RNA inside the shell. The outer shell spikes bind particularly well to a surface protein on our cells called ACE2. How “sticky” a virus is determines how infectious it is – and this one is very sticky. Once attached to a cell, the virus “activates” by splitting one of the spikes using a chemical produced by quite a few of our cells called “furin”. Then it can inject the RNA into our cell and hijack it. What makes SARS-CoV-2 so nasty is it attacks both upper and lower respiratory cells. We think it may transmit itself while still in the upper respiratory tract where it doesn’t cause many – or any – symptoms. Then it penetrates the lower tract (lungs) potentially causing pneumonia. Even that wouldn’t be so bad, but in certain people, the immune system unleashes a violent immune reaction which causes release of various chemicals – termed “cytokine storm” and this can cause tissue damage from friendly fire as well as leaky blood vessels (fluid in the lungs), kidney damage and heart damage. The lungs clog with dead cells and fluid, kidneys shut down and sepsis (widespread infection) overwhelms the body, ultimately shutting down blood cell production (septic shock, bone marrow suppression). If you’re already elderly or compromised by another disease you may not survive this. This points to the first answers for some of the confusion around possible treatments for this. In already infected people, sometimes inhibiting some of these more counter-productive immune responses can help them – hence the trialing of various high blood pressure drugs and anti-inflammatories. But these drugs do NOTHING to prevent viral spread or kill the virus.

So how about infectivity – the ecology of this virus as it were. We’ve already seen how sticky this particle is – so how does it invade? Generally by either being introduced into our nose/eyes/mouth through an infected person coughing, sneezing or talking, or by being deposited on our surroundings and transferred to our nose/eyes/mouth (the “T zone”) by our hands. The range of infectivity appears to be less than 2 meters (6 feet). Stay that far away and the chances of direct human-to-human transmission drop dramatically (social distancing). Again - this virus is not airborne the way others, like measles, can be.

It now appears from at least one Chinese study that asymptomatic transmission can occur – which is bad if it’s true. WHO said this was highly unlikely in a statement Feb 1, 2020 – however this more recent study theoretically suggests it may be actually common. Normally, respiratory viruses only shed during symptomatic disease – the person feels sick, coughing and sneezing. This one may be able to shed from the upper respiratory tract before the infected person feels ill.

The virus has also been found in other secretions such as bowel contents – diarrhea – this currently is not thought to be a major route of person-to-person spread – but some researchers are questioning this – and this unproven theory is important for you to know! The other tissue that has a lot of ACE2 receptors is your gut - from stomach to rectum. Anal swabs have been found to be positive in 52% of Covid cases. This same article notes the infection tends to swab positive first in the respiratory tract, and later in rectal swabs - after the nasopharyngeal ones have turned negative.

Sorry – the next bit is kind of gross. The work comes from super-outbreaks on board luxury cruises. We know how norovirus spreads aboard cruise ships – fecal-oral route. People do not wash their hands appropriately following a bowel movement. They touch things like hand railings – or worse – prepare your food or drinks – and the virus spreads like wildfire. Researchers are raising the possibility that, since we know corona virus is shed in significant numbers in bowels – maybe this route is another important means of spread. This can be stopped in its tracks by WASHING YOUR HANDS – REALLY WELL.

As far as virus surviving outside its human host, the virus has been shown to survive on plastic or steel for up to 3 days, cardboard/paper 1 day and copper 4 hours. Hence cleaning surfaces at least daily is important, as is frequent hand washing.

So what are the symptoms? As firsthand accounts flood the internet we are getting a more accurate picture. For the vast majority of people with the infection it is just a very nasty, multi-wave infection causing profound fatigue, muscle aches/weakness, dry cough and mental fogginess. Fever, often coming and going, of around 101 degrees F seems common. Here is a table of symptoms from the most definitive study we have to date:

“Symptoms of COVID-19 are non-specific and the disease presentation can range from no symptoms (asymptomatic) to severe pneumonia and death. As of 20 February 2020 and based on 55924 laboratory confirmed cases, typical signs and symptoms include: fever (87.9%), dry cough (67.7%), fatigue (38.1%), sputum production (33.4%), shortness of breath (18.6%), sore throat (13.9%), headache (13.6%), myalgia or arthralgia (14.8%), chills(11.4%), nausea or vomiting (5.0%), nasal congestion (4.8%), diarrhea (3.7%), and hemoptysis (0.9%), and conjunctival congestion (0.8%).”

This study suggested 80% will have mild to moderate disease with no or mild pneumonia, 14% will have severe disease with pneumonia and respiratory compromise, and 6 % life threatening multisystem disease.

Onset of symptoms is highly variable depending on which study one reads. The Chinese study suggested a mean of 5-6 days following exposure (but the range was 1-14 days).

Death rates are highly controversial – as they depend on how many people are tested. Initial estimates of a 3-4% death rate now seem high, and Germany is currently reporting 0.3%. Britain is 4.6% while Italy is 9% - but these numbers are strongly influenced by a relative shortage of testing. The other key issue is the characteristics of those experiencing more severe illness. It appears to skew more towards older patients – above age 60, and obviously those with other health problems such as chronic respiratory disease, immunosuppression, diabetes and more severe cardiovascular disease.


This is the meat of the subject. People want to know what to do. Here an aviation analogy is apt – the safest (zero risk) flight is one that never leaves the ground. Those pilots seeking to minimize their risks as low as possible should never leave the house. This is impractical to say the least. Groceries need to be purchased, children transported etc. Aviation is all about acknowledging risk and mitigating it, not demanding it be zero. Applying what is already known, here are the best current practices.

The most obvious statement is do not report to work if you are unwell. Any of the foregoing symptoms should result in a book-off and behaviour consistent with a presumptive diagnosis of Covid-19 (i.e. if on a pairing immediate contact with Flight Operations, self isolation when appropriate and mask wearing, rigorous hand cleansing during transport back home.

Social isolation – stay 6 feet away from others when possible. If you wish to chat do it via cell phone or other media – not face-to-face unless unavoidable. Flight crew tend to be sociable creatures – this is not appropriate now. CRJ cabin width is 7 feet 1 inch – the cockpit is narrower. 737 cockpit is 2 m – so obviously crew are going to be within the social isolation zone. That means rigorous observance of behavioural measures to limit aerosolization of saliva/secretions (cough/sneeze into the crook of the arm, no close quarters talking – use the intercom). Rigorous hand cleansing with sanitizers should be performed. No touching of one’s T zone without first cleansing. This information and more on aircraft cleaning has been published by EASA. ALPA has also published some advisory documents. Most of these are pretty generic.

The cockpit should be wiped down using approved cleaners prior to use. A list of cleaning solutions appropriate for Covid-19 eradication has been published by the US EPA, although not all of these may be acceptable for use in aircraft.

Socializing during pairings (crew dinners, going sight-seeing etc.) should be eliminated as much as possible.

Everyone should be carrying a thermometer on pairings. If you feel ill one of the first questions any health professional will ask is “do you have a fever?” Without a thermometer you can’t be sure. Everyone should be carrying a nail brush. Clean under your nails for 20 seconds while hand washing, as many times a day as you can – but certainly every morning and night. Carry one or more bars of soap – that way you know you’ll always have access.

If you become ill during a pairing – you will have been issued a mask. Use it. Notify Crew Sked/ Fight Operations immediately and follow their direction. You must be returned home as safely and expeditiously as possible. If you are having difficulty breathing it is not safe to fly and you must be medically assessed. The local health authority will have guidance on this in Canada.


As a physician in a pandemic I am being asked a steady stream of questions. As we learn more, the answers are changing. I will add to this list as the questions come in – if they seem to be of general interest.

1. I have an underlying health condition – or someone in my family does – should I be flying?

This is actually more philosophical question than a medical one. As I stated the only 100% safe flight is one that never leaves the ground. If you wish to minimize risks to yourself or to others to a maximum extent, then you should not fly. The challenge this represents is that the next question that always follows this one is whether the affected employee should apply for short-term disability. Unfortunately, disability insurance plans cover actual illness, not potential illness. Anxiety over getting ill does not constitute a disability in the definition of most plans. That being said, please consult your benefits people for more specific information. Various insurance companies have put up information sheets on their websites. Consult them too.

2. My medical certificate was not valid on March 17 – but I’m fit to fly now – can I get a medical?

No – Civil Aviation Medicine has forbidden Civil Aviation Medical Examiners from performing medicals without specific permission from the Regional Aviation Medical Officer for the time being. This is only being granted currently in essential public safety interests (eg. police pilots, fire suppression pilots).

3. Is it safe to be flying?

This is a variation on question 1. Nothing is totally “safe”. However it is my opinion that aircraft cockpits are being cleaned more rigorously than most other public venues, there is low traffic through them (unlike, say, grocery stores), air is HEPA filtered and heated to high temperatures in compressors/air packs, pilots tend to follow rules – they will likely follow these social hygiene ones – while the public tends not to.

4. Should I wear a mask or gloves on pairings?

Masks are ineffective in filtering viral particles as explained above. The only value is in trapping saliva or cough droplets in an ill person. The only other slight value that can be argued is they may remind you not to touch your T zone. Likewise, gloves get contaminated and people don’t tend to wash their hands when wearing gloves. So use them to gather trash if grooming, then discard. Wash your hands for 20 seconds at a time!

5. I heard that xxx is being used to treat this – does it work?

There are lots of suggested treatments – from some of the antiviral drugs used in fighting HIV/AIDS to some older drugs like chloroquine or hydroxychloroquine . Three anti-virals - favipiravir, remdesivir, and ritonavir are being trialed currently. No decision yet on their effectiveness – however a combination of ritonavir and lopinovir in China recently proved ineffective in treating Covid-19 pneumonia. In February China published some results showing potential benefit in using chloroquine in others suffering from Covid pneumonia – and this is being pursued by other countries. Vaccines have been developed in the past against other types of corona virus – so theoretically we should be able to fast track this. Initial clinical trials have already begun. Realistically we are 12-18 months away from having a widely available tested vaccine for use.

There are many other drugs from monoclonal antibodies to novel antibiotics in initial testing. None are definitively useful yet.

6. Which is better – hand washing or hand sanitizer?

This is a judgement call, but fundamentally vigorous hand washing with soap is best. Read what CDC has to say here:

(The article unhelpfully refers to “germs” which is meaningless. Coronavirus is an envelope virus – so alcohol works by tearing this apart). Pilots have to weigh up the risks of leaving the cockpit – a controlled environment, and particularly mixing with crowds, or crowded or dirty washrooms, in order to wash with soap and water. If they deem these risks either excessive or unknown – hand sanitizer containing at least 60% alcohol is the next best choice. Take a palmful of sanitizer, carefully coat all areas of your hands, and keep massaging until it all dries. This should take about 1 minute.

Here is a fun readable article that gives similar information:

7. Is it safe to take ibuprofen to treat symptoms of COVID-19?

Some French doctors advise against using ibuprofen (Motrin, Advil, many generic versions) for COVID-19 symptoms based on reports of otherwise healthy people with confirmed COVID-19 who were taking an NSAID for symptom relief and developed a severe illness, especially pneumonia. These are only observations and not based on scientific studies.

The WHO initially recommended using acetaminophen instead of ibuprofen to help reduce fever and aches and pains related to this coronavirus infection, but now states that either acetaminophen or ibuprofen can be used. Rapid changes in recommendations create uncertainty. Since some doctors remain concerned about NSAIDs, it still seems prudent to choose acetaminophen first, with a total dose not exceeding 3,000 milligrams per day.

However, if you suspect or know you have COVID-19 and cannot take acetaminophen, or have taken the maximum dose and still need symptom relief, taking over-the-counter ibuprofen does not need to be specifically avoided.

(This FAQ was sourced directly from and it was well written so I didn’t change anything.)

8. Can coronavirus live on clothing and should I change when I get home?

While we know viruses can live on hard surfaces, softer ones like cloth are less hospitable. Firstly – philosophically – if you can easily change your clothing when you get home after a pairing – why not? There’s no downside. Is this likely a significant mode of viral transfer – all evidence would suggest not. This is a pretty good lay-article on the subject -

You’ll notice all the experts are equivocating and guessing. The theory is that fibrous surfaces like cloth can dry out the virus and deactivate it. So bottom line? Not likely a significant source of risk, however, if you can, go ahead and do it. Don’t freak out if you can’t. What should you absolutely do first thing when you get home? WASH YOUR HANDS – THOROUGHLY! (Are you sensing a pattern here?)

9. I heard a sudden loss of sense of smell (anosmia) could be a sign of Covid-19.

This is anecdotal at this stage – but two groups of Ear Nose and Throat specialists have noted their members are seeing this phenomenon. Here is the quote from the British ENT organization: (Source: )

“Post-viral anosmia is one of the leading causes of loss of sense of smell in adults, accounting for up to 40% cases of anosmia. Viruses that give rise to the common cold are well known to cause post-infectious loss, and over 200 different viruses are known to cause upper respiratory tract infections. Previously described coronaviruses are thought to account for 10-15% cases. It is therefore perhaps no surprise that the novel COVID-19 virus would also cause anosmia in infected patients.

There is already good evidence from South Korea, China and Italy that significant numbers of patients with proven COVID-19 infection have developed anosmia/hyposmia. In Germany it is reported that more than 2 in 3 confirmed cases have anosmia. In South Korea, where testing has been more widespread, 30% of patients testing positive have had anosmia as their major presenting symptom in otherwise mild cases.”

And here is the same observation from America:

10. Why did testing criteria in Alberta change, as of March 23?

(I copied this directly from the AHS Bulletin of March 24. I like it because it explains why a test is not as important as isolation)

“The testing criteria implemented as of March 23 allows us to focus Alberta’s testing capacity on those most at risk. This is consistent with the approach happening across Canada. Our approach allows us to strategically use our testing resources, and reflects the fact that the most important thing anyone can do if they have mild symptoms isn’t to get tested—it’s to stay home and self-isolate. This includes all healthcare workers. Alberta is already a world-leader when it comes to testing for COVID-19. We are confident that Alberta’s testing criteria this provides us with our best chance of fighting this pandemic. The new testing criteria will help all of us, but only if all of us follow the protocols. If you are sick or do not feel well, stay home for 14 days. Are we doing anything else differently for returning travelers,as of March 23? AHS is building extra capacity to be able to provide advice to returning travellers with symptoms, ensuring they are following proper medical directions including staying home and away from others, and monitoring their symptoms. These resources are expected to be in place late in the week of March 23.”

11. Should I wash my face after my hands to prevent Covid?


I was asked this question today – and apparently it comes from some worksite screening advice not produced by any health authority. In these FAQs I am recommending ONLY those things I know to be true and can be verified from authoritative sources. NO AUTHORITATIVE sources are recommending this – and I can see some potential problems. If your hands become contaminated – and you wash them inadequately – and then start washing your face – you may transfer viable virus exactly where you don’t want it – your face! There is no reason non-medical personnel should encounter facial contamination by corona virus. There is no information to support this practice at this time.

Further reading

  1. This is a good, readable article from which some of my material is sourced:
  3. Wikipedia actually has some really good summaries. This quote came from
  7. This is a good, scholarly paper on all the pressing issues concerning Covid. It is quite technical.
  8. This is the WHO myth busters page. They keep adding to it as myths multiply on the internet. So…..cocaine DOESN’T protect against corona….

Brendan Adams MD

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