1976 was the year of the Swine Flu.
Hybrid animal-human flus like that are especially dangerous, they supposedly can provoke cytokine storms. The 1918 flu was one such flu and it’s very high death rate may have been from cytokine storms.
As a result the vaccine was rushed into production and there were suspicions that it could have been causing Guillain-Barre syndrome in about 1,000 people so the vaccine program was halted.
Ah yes, the pig flu! I rarely catch flu, but I had the pig flu in 2009. It was horrible :(