Certain vaccines are live which means they are putting the actual virus into the patient thought the injection. This means people who are immune compromised can’t have these because they will get very sick. This is the only way I know how to answer
Not everything is used when it comes to food but everything is used with energy in the body!
Fruit I think would be the table
Yes if have them in the refrigerator for a long time and then take them out and leave them on the counter for a good 2 days