Antibiotics are small molecules or compounds that are effective in treating infections caused by organisms such as bacteria, fungi and protozoa.
Vaccines are dead or inactivated organisms or compounds that are used to provide immunity to a particular infection or disease.

Antibiotics are classified according to their structure and mechanism of action into 3 classes: cyclic lipopeptides, oxazolidinones & glycylcyclines. The first 2 are targeted at Gram positive infections and the last one is a broad spectrum antibiotic.
Vaccines are of different types-live and attenuated (vaccines against chicken pox), inactivated (BCG vaccine), subunit (Hepatitis C), toxoid, conjugate, DNA , recombinant vector vaccines and other experimental vaccines.

Side effects
Some antibiotics may have side effects like diarrhea, nausea and allergic reactions.
Some vaccines may cause allergic reactions.

Antibiotics can be derived from natural, semi-synthetic and synthetic sources.

Sources of
 vaccines include live or inactivated microbes, toxins,antigens, etc.