COVID-19
General Eye Health

How Doctors Think About COVID

     We are about a year into this pandemic and one thing is perfectly clear.  The main feature of this virus is confusion!  Should we wear a mask?  Should we open schools?  Why are bars open but churches closed?  On and on and on.  Unfortunately, there has been a tremendous disconnect between how doctors think about the virus and putting a public policy in place.  Most of the time, the two do not sync up very well.  In this article, I am going to try and explain how doctors think about viruses and let you conclude what is and isn’t reasonable.

What are Viruses?

     I had better start by explaining the nature of viruses.  This may be the most critical part.  They are one of the most fascinating things in nature.  First of all, viruses are not even alive.  Living cells have certain characteristics.  They eat, move, reproduce and die.  Viruses do none of these.  They cannot exist for very long outside of another living cell.  They are merely packets of genetic material (proteins) that take over other living cells and turn them into little virus factories.  Let’s take the common cold virus.  The lining of your upper respiratory tract produces a thin layer of mucus to smoothly coat your airway.  When you inhale water droplets from someone else with a cold, the virus particles attach to the cells in your airway.  They penetrate the walls of the respiratory tract cells and insert their genetic material in place of these cells.  The respiratory tract cells, instead of producing other normal respiratory tract cells now become little virus factories.  All of that “snot” you cough up and sneeze all over the place are mucous and water droplets chalked full of brand-new virus particles ready to infect someone else.  The only way to stop the spread of a virus is to prevent it from finding a new host to take over.  You can’t even kill a virus since it is not alive to begin with.  If it does not find a new host once it is released into the environment, the virus protein will disintegrate and no longer be infectious.

What Are the Risks of Me Getting Sick?

     I had better start by explaining the nature of viruses.  This may be the most critical part.  They are one of the most fascinating things in nature.  First of all, viruses are not even alive.  Living cells have certain characteristics.  They eat, move, reproduce and die.  Viruses do none of these.  They cannot exist for very long outside of another living cell.  They are merely packets of genetic material (proteins) that take over other living cells and turn them into little virus factories.  Let’s take the common cold virus.  The lining of your upper respiratory tract produces a thin layer of mucus to smoothly coat your airway.  When you inhale water droplets from someone else with a cold, the virus particles attach to the cells in your airway.  They penetrate the walls of the respiratory tract cells and insert their genetic material in place of these cells.  The respiratory tract cells, instead of producing other normal respiratory tract cells now become little virus factories.  All of that “snot” you cough up and sneeze all over the place are mucous and water droplets chalked full of brand-new virus particles ready to infect someone else.  The only way to stop the spread of a virus is to prevent it from finding a new host to take over.  You can’t even kill a virus since it is not alive to begin with.  If it does not find a new host once it is released into the environment, the virus protein will disintegrate and no longer be infectious.

What Are the Risks of Me Getting Sick?

     Here is where the confusion lies.  Not all viruses and situations are alike.  What determines if you get sick?  After all, that is what we really want to know.  There are 5 main areas that we need to look at to figure out your risk of getting sick.

  1. Virulence
  2. Contagiousness (R0)
  3. Size of Inoculum
  4. Time of Exposure
  5. Susceptibly of the Host

Virulence

     Virulence is a pathogen‘s or microbe‘s ability to cause damage to a host.  Basically, how nasty is the bug.  One of the most virulent organisms in history was the “Black Death” from 1346 to 1353.  It was caused by a bacterium that killed a third of the European population at that time.  In other words, if you got sick with this disease, your chance of survival was very slim.  On the other hand, a common cold virus is very contagious but not very virulent.  Most of the time you will be just fine in 7-10 days.

Contagiousness

     How likely is the virus to spread and find a new host?  We measure this with a number called R0 (pronounce R naught) or reproduction number.  How many other people will you infect?  If R0 is less than 1, each existing infection causes less than one new infection. In this case, the disease will decline and eventually die out.  With an R0 of one, a single infected person is likely to give the virus to one other person.  The disease will stick around for a while but not cause an epidemic. With an R0 greater than 1, the same person will likely infect more than one other person and may lead to an outbreak or epidemic.  COVID-19 was originally thought to have an R0 around 2.2 to 2.7.  We now know that it has been reported as high as 5.7.  One of the worst is measles with an R0 of around 12-18.  That means one person infected with measles will give it to 12 to 18 other people.  The R0 for seasonal flu averages 1.28. 

Size of Inoculum

     This refers to the number of infectious particles to which you are exposed.  Picture someone smoking.  As they exhale, a thick cloud of smoke leaves their mouth and nose, which gradually gets thinner as it spreads out.  Viruses are the same.  When you are infected and you exhale, talk, sneeze, cough, yell, scream or shout, you expel a massive cloud of viral particles which dissipate with distance much the same a cloud of cigarette smoke does.  The closer you are to the infected person, the large the number of virus particles and the greater your chance of becoming infected.  You can see from this example that there is nothing magical about the 6-foot distance rule.  It’s not as if you are in terrible danger being 5’11“ away from someone and perfectly safe being 6’1” away.  It’s all relative.  It reminds me of the old smoking/nonsmoking sections in restaurants.  As if a line on the floor and a sign are going to stop the cigarette smoke from crossing over.

Time of Exposure

     This one is pretty straightforward.  The longer you are exposed to an infectious agent, the greater your chance of getting infected.  If you have a small cut on your finger and briefly dip it into some filthy pond water, chances are you will be fine.  If you soak it in the same water for an hour, the result may be a lot worse.  Someone without a mask who jogs by you on their morning run and says a quick hello is far less likely to infect you compared to someone sitting near you in a restaurant and eating for an hour.  Time of exposure matters.  Keep it brief.

Susceptibility of Host

     In other words, how healthy are you?  The best thing you can do is take care of yourself.  You know what to do.  Eat a healthy diet, exercise regularly, and get plenty of sleep.  The same advice doctors have been giving patients since I was a little kid.  Work with your doctor to get as healthy as possible.  I know many people have chronic diseases through no fault of their own, which makes them more vulnerable to infection.  Even little things like improving your diet, taking your medications, or just moving increase your chances of staying out of the ICU.  My father once told me when I was a kid, “Take care of #1.  If you don’t, nobody else is going to do it for you.”

     Now that you know how doctors think about this pandemic, you can see how difficult this is to translate into public policy. Should schools be opened or closed?  Why are churches closed but bars open?  Should we, “Let Them Play”?  Why do professional and college coaches wear a mask on the sideline yet pull it down to yell at players and referees?  Viruses could not care less about the city, county, or state lines, about red or blue states, about personal freedoms or rights.  Their sole purpose is to infect you and turn you into a virus-producing factory, even if it kills you.

     This all reminds me of a story I once heard about a man whose house sat on the border of Russia and Finland.  The Russian government census officials approached him one day and told him he needed to decide if he was going to be a Russian or Finnish citizen.  This gentleman greatly appreciated the Russian government for they had provided him with much support over the years.  He told the Russian officials “I greatly appreciate all you have done for me over the years but I have decided to be a Finnish citizen.  I love Russia and the government, but in my advancing years, I just can’t take the Russian winters any longer.”

     Think about the pandemic in the above terms and it may help make sense (or nonsense) about all of the craziness out there.  Use this information to take care of yourself and your loved ones.  Be smart and stay safe.

     This newsletter does not constitute medical advice.  Make sure to contact your healthcare provider if you experience any of these conditions.  Do not make any changes to your medications before consulting your physician.

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