There is plant-based squalene too. Also, I really don't understand the logic of putting sharks' lives before humans. If we need to kill all sharks to save humanity, then so be it.It's not just the possibility of the vaccine not working, conservationists are claiming that if everybody got one dose of vaccine, another 250.000 on top of the 3million sharks currently being killed for their squalene for human use. Squalene supposedly enhances the vaccine by creating a stronger immune response.