Answer:
Negative feedback occurs when a system's output acts to reduce or dampen the processes that lead to the output of that system, resulting in less output. In general, negative feedback loops allow systems to self-stabilize. Negative feedback is a vital control mechanism for the body's homeostasis.
The balanced reaction would be:
2 C4H10 + 13 O2 ----> 8 CO2 + 10 H2O
Like this both side of the reaction would have:
8 atoms of C
20 atoms of H
26 atoms of O
I think its because vaccines are just to help your body learn how to fight off the virus, it’s not to actually give you the virus. Hope this helped!