That's one opinion. Here's another that has some strong evidence behind it:

"The 1918 flu was first observed in Europe, the United States and parts of Asia before swiftly spreading around the world."

Then they finally tell the truth later in the article, while still trying to hide the fact that it originated in the US:

"Scientists still do not know for sure where the Spanish Flu originated, though theories point to France, China, Britain, or the United States, where the first known case was reported at Camp Funston in Fort Riley, Kansas, on March 11, 1918."

The first known case was reported on a military base that was working on a meningitis vaccine...coincidence? Of course the vaccine didn't cause the Spanish flu, but it likely weakened the immune systems of all the soldiers that eventually caught the flu and eventually bacterial pneumonia.