Here, President Donald Trump gets a lot confused.
Colloquially, the Spanish Flu is known as 1918 flu pandemic.
Due to World War 1, news of the pandemic was censored in the United States. Newspapers in Spain, a neutral country during WW1, were able to report on the pandemic. Because of this, people assumed that Spain was extraordinarily hard hit by the virus relative to other countries.
1918 Flu Pandemic and the end of World War II
The 1918 flu pandemic was not the proximate cause of the cessation of hostilities in Europe and Japan.
In Europe, immediate hostilities ended after Adolf Hitler committed suicide and Berlin was taken by allies. The U.S. didn’t formally end hostilities with Germany until 1951.
In the Pacific, hostilities ended only after the United States dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki. These attacks instantly killing thousands of Japanese civilians. Following these bombings, the United States and Japan signed a peace treaty on September 2, 1945.