C. Are There Concurrent Causes?

There may be other factors that have an effect on the death rate.  One factor is the existence of multiple concurrent causes.  Concurrent causation is where two or more causes combine to cause the result.  It happens so often that there is a standard jury instruction given in most civil trials. 

For example, did the failure of the automobile braking system cause the accident, or was it the fact that the driver was speeding at the time, or was it a combination of both.

Concurrent causation is the rule not the exception

Concurrent cause must be a substantial cause in bringing about the result.  It is not any potential contributing cause.  It must have a direct, substantial affect on the outcome.  There is evidence of  concurrent causation between COVID-19 and influenza. 

1.  Combination of COVID-19 and Influenza.  The flu season is widespread in most of the 50 states from January until mid-March.   Resulting deaths usually lag behind the infections by about 3 to 4 weeks, depending on how quickly the deaths are officially reported.  The peak deaths on April 21, 2020 would translate to a March 21-28 infection date.  That time window corresponds with the vast majority of the states having influenza rated as being widespread. 

Few would dispute that both influenza and COVID-19 were present at the same time, at every location.  

The data further illustrates that the majority of the victims had the influenza virus.  This is shown in Figure 5 which depicts data from the CDC on the influenza virus presence tracking.  The dramatic rise in influenza deaths, shown at the right hand side of the graph, is due to the co-existence of influenza and COVID-19 viruses.  

Figure 5 is the United States Flu & Pneumonia Weekly Deaths. The circles indicate common fluctuation in the peaks before it begins to go down. The horizontal axis is the number of weeks from Sept 2015 to April 2020. The vertical axis is the weekly deaths. Data from the CDC.

Figure 6 shows the influenza presence in the US over the last 7 years. This is a computation of the data shown in the Flu Map published by the CDC. It tracks how the influenza virus spreads across the United States. The influenza rating in Figure 6 was obtained by assigning “0” to no activity, “1” to sporadic activity, “2” to local activity, “3” to regional activity, and “4” to widespread activity.

Figure 6 is the Influenza Spread Rating for the United States from 2013 to 2020. The horizontal axis is the state number, including the District of Columbia and Puerto Rico. The vertical axis is the accumulated Flu Spread Rating. Data from the CDC.

The places with the lowest influenza spread rating had a dramatically lower COVID-19 death rate.  This is shown by the green shading.  Conversely, the six states with the highest influenza presence had a ten times higher death rate, illustrated by the yellow shading.  It is possible that this could be a coincidence, but the timing tends to negate that.

There is also support from a hemispheric comparison.  The COVID-19 virus spread out of China, throughout the world, via air travel.  Up until now, the only place in the world where COVID-19 has had a high death rate has been in the Northern Hemisphere.  This is consistent with a high influenza presence.  The Southern Hemisphere, on the other hand, has had a low influenza presence and a correspondingly low COVID-19 death rate. 

The influenza season is now beginning in the Southern Hemisphere, with peaks usually occurring in July and August [Australian Government Department of Health Influenza Season, Summary for each year].  Under a concurrent cause analysis, it may be a good idea for everyone in the Southern Hemisphere to protect themselves. 

Figure 7 plots the weekly influenza presence in 2020, from the CDC Flu Map, superimposed over the plot of weekly COVID-19 deaths.  A 3-4 week delay is applied between the date of infection and the date of death. Another 2 to 3 week delay is applied between influenza’s presence and the time of infection. 

Figure 7. Influenza Spread Rating superimposed on COVID-19 Deaths for 2020. The horizontal axis is the number of weeks from March to December 2020. The left hand side vertical axis is Weekly Deaths in the US. The right hand side vertical axis is the weekly Flu Map Rating total for all 50 states plus Puerto Rico and the District of Columbia. Data used is from the CDC weekly Flu map.

Figure 7 shows a strong relationship between the drop in influenza presence and the drop in COVID-19 deaths.   The influenza Flu Map data stopped in May 2020 and it appears that 100% of the flu deaths were then classified as COVID-19 deaths.  This is unlikely since the graph in Figure 5 showed that for a normal flu year during the summer months from all prior years there were approximately 2,800 to 3000 flu and flu caused pneumonia deaths each year.   For that to stop for no apparent reason, does not make sense.  The CDC does not explain why this is happening nor do they explain why they changed their procedures for 2020.

On September 1, 2020, the CDC put out an update on the coronavirus and its connection to co-morbidities.  In Table 1, Column 2 it reports that the deaths involving COVID-19 was 169,419.  Column 5 reported pneumonia deaths “that also involve COVID-19” but excludes “pneumonia deaths involving influenza” was 173,669.  Column 6 reported COVID-19 deaths and pneumonia deaths but excluded influenza deaths to be 75,199.  Column 8 reported COVID-19, pneumonia, and influenza deaths to be 273,560.  Subtracting column 8 from column 2 yields the number of pneumonia and influenza deaths to be 104,141.  This means that the number of deaths from COVID-19 is 62% of the total and pneumonia and influenza deaths is 48%.   Column 7 reports that influenza deaths that did not involve pneumonia was 6,657.  This suggests that almost all influenza deaths causes pneumonia.  This is consistent with studies that connect influenza deaths to pneumonia.  [Noymer A, Nguyen AM. Influenza as a proportion of pneumonia mortality: United States, 1959-2009. Biodemography Soc Biol. 2013;59(2):178-190.]

The CDC reported number of pneumonia and influenza deaths in 2018 was 191,680 [CDC National Center for Health Statistics-Data16].  This study suggests that COVID-19 and Influenza are related.  It also supports that COVID-19 and Influenza/pneumonia have essentially the same morbidities (180,000+ = COVID-19 deaths to 191,680 = 2018 influenza/pneumonia deaths).

A study out of Italy compared Covid-19 deaths between people that had a Flu shot and those that did not.  It showed that people without a flu shot had around 12 percent deaths whereas those that had a flu shot had a death rate of around 6 percent.  That is a very large and significant difference showing the existence of a possible concurrent cause situation.

2. Combination of COVID-19 and Other Diseases.   It is also possible that the COVID-19 virus may be combining with other diseases.  Heart Disease is a prime target.  Substantial research would be required to establish this pathway. 

3. Combination of Influenza and Common Cold.   A randomized study of 36,000 people showed that 35% tested positive with the influenza while only 8% tested positive for the cold virus. 

One researcher opined that the two viruses were competing for the same host cells and so one backed off.  She gave the analogy of a lion and a spotted hyena’s competition for the same food.   

But that does not fit with COVID-19.  COVID-19 struck while the influenza virus was at its peak.  If competition for the host cells was an issue, it’s unlikely that we would see much overlap between the two viruses. 

Biology is very complicated and, if anything, it illustrates why mathematical models are always poor predictors.