Coronavirus: Breaking the chain

The graphic illustrates the CDC's Chain of Infection for the coronavirus, or COVID-19.

In 1918, the world experienced an extremely deadly pandemic known as the Spanish flu.

In the end, nearly 30% (500 million people) of the world became infected and 17 million to 50 million people died. 

At that time, the world was engulfed in World War I, men were in trenches and there was no opportunity for people to practice social distancing.

People were not told to wash their hands carefully. Hospitals were quickly over-run, the virus ran rampant and millions lost their lives. 

This is 2020, and we have the advantage of knowledge, history and science on our side. We can listen to scientists, look to the past and minimize the risks of COVID-19.

COVID-19 is presumably a zoonotic infectious disease, meaning it originated in an animal and jumped to humans. 

The most likely reservoir is a bat. Just like with influenza coming from birds or pigs, the bat coronavirus and an unknown animal coronavirus infected the same cell in that unknown animal. Then that animal came in contact with a human and COVID-19 was the result.  

Jill Henning

Jill Henning

The issue with COVID-19 is that it is very contagious and has the ability to make people very sick. The current stats say that 80% of the people who get COVID-19 will be sick but only have to stay at home; they will not need a hospital.

About 6.1% of people who get sick, no matter their age or immune status, will require hospitalization and ventilator support. This is scary because it will cause our ICU beds to be overrun and create massive issues with access to health care.  

Thus, if 1,000 people in a community get sick, then 61 people will be in ICU. Hospitals cannot accommodate that many ICU patients. The other issue is the mortality rate of 3.4%. This is an average over all ages, but if you are over 65, the mortality rate is 10% (this is the same if you are immunocompromised).

So let’s go back to the 1,000 people; 34 people die in total (approximately 100 if the population is older), 61 in the hospital and likely the 34 would be in-patient before death (95 people).

So mathematically speaking, you could have between 95 and 195 people in the hospital in need of ICU in a population of 1,000.

Scale that up for a larger population and you can see the issue. 

The city of Johnstown has approximately 21,000 people and Conemaugh Memorial Medical Center has a pulmonary ICU of 25 beds. Figures so far indicate that as much as 6.1% of the infected population requires an ICU stay (average of 10 days long). If everyone in Johnstown gets infected, the infected need to be spread over a period of 510 days to not overwhelm ICU capacity.

This also assumes that no one else from outside of Johnstown needs to go to the Conemaugh ICU and that there are no non-COVID-related cases requiring a visit to the pulmonary ICU over those 510 days.

This isn’t what the flu does to a population. Who wants to be the person that has to choose who gets the ventilation and who doesn’t? This is the current situation that Italy is in. 

If we take the same 1,000 people in a community and use the current stats for influenza, this is how it would look. The mortality rate for influenza in 2018-2019 was 0.02%. During the 2018-19 flu season, about one out of every 1,000 people died. Thirty-four people dead from COVID-19 is a lot more dead than one.

We can also learn from other countries. South Korea has lowered its infection rate by testing at extremely high rates and isolating all cases of COVID-19, and also sharing all of its data with its citizens. Italy was slower to test. Its infection rates have skyrocketed, its hospitals are over-run and it is choosing who to ventilate and who to allow to die. 

So, what can you do? You can socially distance yourself. You may get sick and be OK, but your elderly neighbor may not have it so lucky. 

Stay home. Wash your hands regularly.

If you are looking for resources, Pitt-Johnstown has compiled a great resource bank on its website: coronavirus toolkit – Pitt-Johnstown – University of Pittsburgh › coronavirus-toolkit.

It is full of helpful info about the virus and how to keep safe.

Jill Henning is a professor at Pitt-Johnstown. Professors Christine Dahlin, Luis Bonachea and Paul Newman contributed to this column.

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