Influenza: 1968 Hong Kong Flu

Hi, I'm Hong Kong flu.
I started out as my 1957 friend.
In 1968 I went through antigen shift,
I then became H3N2 and spread.
I moved from China to Hong Kong.
I lasted for 2 years.

I was milder than my earlier flu friend.
Not as many people died.
I also came from mixing of human and bird strains.