Most of the vaccines we receive have origins in bacteria. The vaccine is made of germs that cause the disease, but are in an inactive or weakened form so you don't get sick.

Usually, the flu vaccine is made in chicken eggs. There are three vaccines that use gelatin from pigs to make the vaccine more stable in storage. They are three variations of the flu, MeaslesMumpsRubella (MMR), and adult shingles vaccine that use this gelatin from pigs.

However, yes, there are many other options for these vaccines which are equally effective.