I have heard, with some alarm that the flu c]vaccine has elements of shark in them, and this is used to help boost immunity

And for those of you that may have been asleep, we are in the middle of a virus pandemic, yet I have not once heard of recommendations of how to boost your health and immunity during such times. Surely, our immune system is the bit that protects us, reduces the impact of the virus and ultimately keeps us alive, yet I hear nothing about how we can help ourselves, other than use a hand gel to kill bacteria