You cannot get the disease from a vaccine.
Most vaccines are inactivated vaccines. This means they have no living bacteria or viruses in them, so they cannot cause disease.
Messenger RNA vaccines (called mRNA vaccines) are a new type of vaccine. Some of the vaccines for COVID-19 are mRNA vaccines. These types of vaccines also do not contain any living bacteria or viruses and cannot cause disease.
Some vaccines, such as vaccines that protect against measles, mumps,
rubella, varicella (chickenpox), or rotavirus, have weakened forms of these viruses. These are called live vaccines.
Live vaccines do not cause disease in healthy people, but they could cause disease in people with a weak immune system. Your healthcare provider will always ask you questions about your health and medicines before you get a vaccine to make sure the vaccine is safe for you.
Some people with a weak immune system may be able to get live vaccines safely, depending on how weak their immune system is. Your healthcare provider will help you decide what is best for you.