system
Given the following post, respond as if you're commenting on Reddit:
human
Why was the 2009 H1N1 pandemic less deadly than the H1N1 pandemic in 1918? Was it a less dangerous disease, or did we just have better medicine?
gpt
In addition to what others already wrote, it's also worth pointing out that the 1918 H1N1 virus was a very different one than the 2009 H1N1 virus. 

The HxNx classification system is fairly coarse and is based on two surface proteins of the viruses, but doesn't take other differences into account.