How do pandemics end? Now that COVID-19 vaccines have been approved, we’re all hoping this is the beginning of the end of this coronavirus pandemic. What about a history lesson—how did the last large respiratory viral pandemic end? The 1918 Spanish flu pandemic killed between 50 million and 100 million people, and was the third worst pandemic in the past 1000 years. (Number one was the bubonic plague/Black Death in the 1300s which killed 75 to 200 million people, up to 70% of Europe’s population.1 Number two is the HIV/AIDS pandemic which has killed 32 million people from 1981 to the present.2) How did the Spanish flu pandemic end? There was no vaccine technology in 1918. There were no intensive care units, there were no ventilators, and there wasn’t even a microscope powerful enough to see or identify the virus. There were no anti-viral drugs such as remdesivir or Regeneron’s monoclonal antibodies, and there were no antibiotics to treat the bacterial pneumonias that developed as complications of the flu. When people got a severe case of the Spanish flu, they died. 

H1N1 influenza virus

Novel coronavirus

The difference between the 1918 pandemic and the 2020 pandemic is the fact that the Spanish flu was an influenza virus, and COVID is caused by a novel coronavirus. Both are respiratory viruses, but influenza and coronavirus are two very different entities. Influenza is a seasonal infection which usually runs from autumn until spring. In a typical year, 200,000 Americans are hospitalized for flu-related complications. Over the past thirty years there have been between 3,000 to 49,000 influenza-related U.S. deaths every year. The 1918 Spanish flu pandemic was caused by an H1N1 influenza virus A. It lasted from 1918 to 1920, and infected 500 million people, more than one-third of the world’s population. REF  ). The pandemic killed between 50 million and 100 million people, including 675,000 in the United States. The pandemic occurred during World War I. The press in the United States and much of Europe censored early death tallies from the disease to minimize global panic. Spain was a neutral country in the war, and their newspapers were free to report on the disease, especially since their King Alfonso XIII  contracted the disease. Early stories from Spain created the impression that Spain was hard hit by the disease, and because of this the pandemic was named “Spanish flu.” 

The first wave of the Spanish flu began in the spring of 1918. The second wave began in August, and was more lethal than the first wave. In the United States the peak number of deaths were reported between September and December of 1918.  Infected individuals experienced typical flu symptoms such as sore throat, headache and fever. In January 1919 a third wave of the Spanish flu spread in Europe. The troop deployments and trench warfare of World War I facilitated disease transmission. Death was often caused by bacterial pneumonia  due to common upper respiratory-tract bacteria which invaded the lungs by infecting the viral-damaged airway cells.

Ninety-nine percent of Spanish flu deaths in the United States occurred in people younger than age 65, and fifty percent of the deaths were in young adults 20 to 40 years old. As in the COVID-19 pandemic, the entertainment and service industries suffered heavy economic losses. Public policy on curbing the spread of the Spanish flu was similar to the advice offered in the COVID pandemic: social distancing and masks-earing were encouraged. Frequent hand-washing, quarantining of patients, and closure of schools, public spaces and non-essential businesses were all utilized to minimize the spread of the disease.

How did the Spanish flu pandemic end? Individuals who were infected either died of influenza or survived and developed immunity. In the middle of 1920, the Spanish flu faded away enough on its own so that the pandemic ended.

Let’s compare this to the current novel coronavirus pandemic. As of this week there have been 300,000 COVID-19 deaths in the United States and 1.7 million deaths worldwide. So far less than 1 percent (74 million infected/7.8 billion total world population = .0095) of the world’s population is known to have been infected with the novel coronavirus. While the Spanish flu eventually faded away, as annual seasonal influenza usually fades away, the novel coronavirus has so far showed no signs of weakening. We are nowhere near herd immunity. Herd immunity is defined as “when a large portion of a community (the herd) becomes immune to a disease, making the spread of disease from person to person unlikely. As a result, the whole community becomes protected — not just those who are immune.”  

Doctors don’t expect the current COVID-19 pandemic to end until a significant percentage of the world’s population is vaccinated. According to Dr. Anthony Fauci, “Let’s say we get 75 percent, 80 percent of the population vaccinated. If we do that, if we do it efficiently enough over the second quarter of 2021, by the time we get to the end of the summer, i.e., the third quarter, we may actually have enough herd immunity protecting our society that . . . we can approach very much some degree of normality that is close to where we were before.”

Between twenty and forty percent of Americans say they will not take the COVID vaccine. This is a high number, and it strikes me as lunacy. The health consequences of you, your family members, or your friends developing a severe case of COVID-19 are well documented. Both the Pfizer and the Moderna vaccines showed minimal side effects in their clinical trials. Be smart. Get vaccinated as soon as you can. Herd immunity to the COVID-19 virus will only develop if we vaccinate the populace. Hopefully vaccine-induced immunity will curb the COVID-19 pandemic so the world can once again return to the lifestyles and freedoms we enjoyed in 2019.


  1. Austin Alchon, Suzanne (2003). A pest in the land: new world epidemics in a global perspective. University of New Mexico Press. p. 21. ISBN 978-0-8263-2871-7. Archived from the original on 2019-04-01. Retrieved 2016-04-22.
  2. “UNAIDS report on the global AIDS epidemic 2010”. UNAIDS. UNAIDS. 2010. Retrieved 5 September 2020.




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