Most vaccines are animal based

The most common way that flu vaccines are made is using an egg-based manufacturing process that has been used for more than 70 years. Egg-based vaccine manufacturing is used to make both inactivated (killed) vaccine (usually called the "flu shot") and live attenuated (weakened virus) vaccine (usually called the "nasal spray flu vaccine").

The other two methods are not vegan either. The other one uses mammal cells and recombinant vaccines use animal testing in most cases.