COVID-19 vs Spanish Flu

As the world of the 21st century struggles to rein in the COVID-19 pandemic, many public health officials are looking back at other pandemics for insights that could help shorten and mitigate this crisis. Although there have been many pandemics including the Black Death, HIV, and cholera, the one that historians most often point to is the Spanish flu pandemic of 1918.

There are many similarities between the present pandemic and the one that began in 1918, but the scale of the crises were quite different. To date, COVID-19 has killed more than 100,000 people in the United States, as well as more than 350,000 throughout the world. While this is a staggering number of deaths, it pales in comparison to the 40 million that died during the Spanish influenza pandemic.

The Causes of These Two Pandemics

There is still ongoing research into the nature of the coronavirus that is the cause of our present health crisis, but there are some facts that most virologists agree on about the nature of COVID-19.

  • Like other coronaviruses, the one causing COVID-19 labeled SARS-CoV-2 may adapt to target new species. It has been theorized that SARS-CoV-2 originated in bats and migrated to humans.
  • SARS-CoV-2 is much more lethal than previously discovered coronaviruses because it so readily attacks human cells, especially those in the throat and lungs.
  • SARS-CoV-2 is extremely large with more than 30,000 genetic bases, making it three times the size of HIV or hepatitis C, and twice the size of influenza. This enormous genetic diversity may allow it to recombine more quickly with other SARS-CoV-2 and develop into more problematic strains.
  • Unlike many other viruses, SARS-CoV-2 also has a genetic proofreading mechanism that inhibits mutations.  This is probably why antiviral medications are less effective against SARS-CoV-2 because such drugs induce mutations that blunt the lethality of the virus.

Although the Spanish flu pandemic struck more than a century ago, it wasn’t until recently that scientists unlocked its genetic structure and morphology.  Using the frozen DNA of an Inuit woman who died from the Spanish flu, researchers have uncovered new details of that virus.

  • This strain of influenza is denoted as H1N1 and originated in birds. The 1918 strain had only recently migrated to humans which meant that fewer people had immunity and the virus was particularly lethal unlike older viruses which are more sustainable.
  • Influenza regularly causes globe-spanning epidemics that typically have a mortality rate of about 0.1 percent, but this Spanish flu had a mortality rate of 2.5 percent. The particular virulence of this strain is still not fully understood, but most researchers agree that multiple genetic factors contributed.
  • One clearly important characteristic of the Spanish influenza virus was its ability to rapidly reproduce and remain in the lungs. One study among mice found 39,000 times higher levels of the H1N1 virus in mice lungs than other kinds of influenza.

Similarities between COVID-19 and the Spanish Flu

We are still in the middle of the current COVID-19 pandemic, so it is difficult to guess what the scope and after-effects of this public health crisis will ultimately be, but there are already some striking similarities with the 1918 pandemic. Both the SARS-CoV-2 and the H1N1 viruses were new to human populations which means that there was no natural immunity to them.  This partially explains why the fatality rates of both diseases were significantly higher than seasonal influenza and coronavirus outbreaks.

Like the current pandemic, the 1918 flu had multiple waves—although the current situation is still developing, it is likely to mimic other pandemics. The 1918 pandemic appeared almost simultaneously in the U.S., Europe and Asia before sweeping through the global population. This initial wave in the spring of 1918 was mild with most people recovering from infection.

A second wave followed in the fall of the same year, but with far more lethality. Instead of recovering, many of the infected this time died within hours or days. The most common cause of death was fluid filling the lungs due to secondary infections like pneumonia.

Many researchers believe that a similar mechanism is at work in COVID-19 patients. Like the 1918 flu, COVID-19 produces a massive release of immune proteins called cytokines. This “cytokine storm” primarily targets lung tissue which dies as a result. The resulting condition is pneumonia often followed by oxygen deprivation and death.

Lessons to Be Learned from the 1918 Influenza Pandemic

It is human nature to avoid the unpleasantness of health crises, and this hasn’t changed much in the century since the Spanish flu pandemic. Then as now, many public officials downplayed the seriousness of the health crises. For example, Philadelphia leaders misdiagnosed the cause of widespread illness, labeling it the regular flu, and went ahead with a parade that attracted tens of thousands of city residents in late 2018; in just a few months, the city saw more than 15,000 people die from the Spanish flu.

On the other hand, cities like San Francisco and St. Louis enacted strict policies like banning public gatherings, shuttering schools, and masks in public.  These municipalities saw significantly lower death rates.

Unlike COVID-19 which appears to hit hardest the elderly, the Spanish flu struck down primarily young adults. This may be why fear was so much greater among the general public and why lockdown measures may have been more palatable than they are now.

In the case of both pandemics, there was no treatment at the time. Despite a ferocious effort around the world for vaccines and therapies for COVID-19, there is no treatment that lowers the viral load (although the medicine Remdesivir does appear to shorten hospital stays).

Until a therapy is developed that prevents transmission or counters the effects of the virus, the primary defense is social distancing. As in 1918, the best way to protect the public is limit person-to-person contact which may allow respiratory droplets to transmit the SARS-CoV-2. This means maintaining face coverings while in public, remaining 6 to 12 feet apart and regular hand washing.

Article written by: Dr. Robert Moghim – CEO/Founder Colorado Pain Care

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