04 May It’s no worse than the flu-3
I discussed in the previous blog the importance of the the reproduction number (R0 value). If the R0 value is < 1, then the rate of infection is decreasing. Yet another important aspect of the R0 value is how viruses stack up against each other. You can have a virus that is not likely to kill you, such as the measles, but has a very high R0 value. From the table you can see that for measles 1 infected individual has the potential to infect 12-18 others. The seasonal flu has a R0 value of only 1-2, but it has a significant mortality rate compared to measles. When you combine a high R0 value with significant morbidity and mortality, such as COVID-19, then the stakes become much higher.
|DISEASE||REPRODUCTION NUMBER R0|
|Ebola, 2014||1.51 to 2.53|
|H1N1 Influenza, 2009||1.46 to 1.48|
|Seasonal Influenza||0.9 to 2.1|
|Measles||12 to 18|
|MERS||2 to 7|
|Polio||5 to 7|
|SARS||<1 to 2.75|
|Smallpox||5 to 7|
|SARS-CoV-2 (causes COVID-19)||1.5 to 3.5|
The above chart and cartoon describe the number of additional cases of a disease each infected person will cause during their infectious period. The numbers are a range, because they depend on a variety of factors that vary from situation to situation. As you can imagine, the R0 value for measles in New York City will have more deleterious effects than Elko, NV.
Yet you can also imagine if just one person infected with COVID-19 assimilates into a rural area with marginal healthcare access, this can be worse than urban exposure. If you don’t have the hospital capacity to care for the sick, then you are no better off than being situated in a densely populated area with easy access to hospitals. This is becoming a troublesome factor in all the COVID-19 hotspots centered around meatpacking plants in South Dakota, Iowa, Texas and Colorado.
I understand why people in less populated areas want to lift social distancing restrictions. But there are many other factors to consider. That is why epidemiology is so much more complicated than calculus and logarithmic graphs. There is the human component involving individual’s freedoms and fears. There is the fact that no two bodies will act exactly the same. And most importantly, this is a NOVEL virus. We have no history of how it will act, nor can we predict how it will act. What I can predict is that Dr. Fauci and his team will lead us in the right direction, and I hope that we can give them the respect they deserve and follow their suggestions.