evidence: As a result of having the Spanish flu, many people died from pneumonia and other respiratory illnesses. Some people died on the same day that they became ill. [...] Some of the reasons why the Spanish flu killed so many people include: [...] COVID-19 has killed as many people in the U.S. as the Spanish flu did. But the population of the U.S. is now three times more than it was in 1918, so Spanish flu killed a larger percentage of Americans than COVID-19 has to date. If we look at the cause of death, people who had Spanish flu generally died from pneumonia and people who had COVID-19 died from multiple organ failure. Even in the case of people who developed ARDS after infection by each virus, the fatality rate was 100% for Spanish flu, as compared to 53.4% for COVID-19 because there were no treatments for infected individuals. The Spanish flu was also more deadly to healthy younger people, while COVID-19 has mostly affected people who are 65 years or older who have other diseases until the delta variant, which is infecting younger and healthier people more than prior COVID-19 variants.