What is the difference between a virus and bacteria?
Bacteria are tiny living cells that can reproduce on their own, while viruses are much smaller particles that can only multiply inside the cells of another living thing.
Bacteria are single-celled organisms with their own machinery for making energy and copying their DNA. They live almost everywhere, including in soil, water and our bodies. Most bacteria are harmless or helpful, such as those in the gut, but some cause illnesses like strep throat, tuberculosis and food poisoning.
Viruses are made of genetic material, DNA or RNA, wrapped in a protein coat. They cannot eat, grow or reproduce on their own. Instead, they enter a host cell and take over its machinery to make copies of themselves. Colds, flu, measles and COVID-19 are caused by viruses.
Why it matters for treatment
Antibiotics can kill bacteria or stop them from growing, but they do not work against viruses. Taking antibiotics for a viral infection does not help and can contribute to antibiotic resistance. Viral infections are prevented with vaccines and sometimes treated with antiviral medicines.
Did You Know?
Viruses can infect bacteria too. These viruses, called bacteriophages, are being studied as a possible treatment for infections that resist antibiotics.