Vaccines are used for protection against potential future infection and designed to induce a protective immune response in your body. The specific, protective immune cells have a memory element to protect for any future infection by that particular virus. These memory cells allow for a quick response so that when exposed to that virus, you are quickly protected and can avoid becoming ill.
Antibiotics are effective for eradicating bacteria but do not have any effect on viruses. Antibiotics are used when there is a current bacterial infection present. Inappropriate use of antibiotics is a growing concern globally now, with some bacteria developing antibiotic-resistant strains, like Methicillin-resistant Staphylococcus aureus (MRSA) , ESBL E Coli or Carbapenem Resistant Enterobacteriaceae (CRE), resulting in certain antibiotics becoming ineffective. You can read more about drug-resistant bacteria here and how Antibiotic Research UK is tackling this problem.