How Do Vaccines Work?
Vaccines train your immune system to recognize and fight specific pathogens without causing disease. They contain harmless pieces of a virus or bacteria (or instructions to make them) that trigger an immune response. Your body creates antibodies and memory cells that remember the pathogen, allowing a faster, stronger response if you encounter the real disease later.
Key Takeaways
- Your immune system naturally fights pathogens by recognizing foreign proteins (antigens) and creating antibodies to neutralize them.
- Some vaccines require boosters because immunity wanes over time or the pathogen mutates.
- Herd immunity occurs when enough people are vaccinated that the disease cannot spread easily.
Explanation
Your immune system naturally fights pathogens by recognizing foreign proteins (antigens) and creating antibodies to neutralize them. This process takes time during first exposure, which is why you get sick. Vaccines introduce antigens safely, letting your immune system practice without the dangers of actual infection.
Different vaccine types include: inactivated vaccines (killed pathogens - flu), live-attenuated vaccines (weakened pathogens - MMR), subunit vaccines (pieces of pathogens - hepatitis B), and mRNA vaccines (instructions to make harmless spike proteins - COVID-19). All trigger the same immune learning process through different mechanisms.
After vaccination, memory B cells and T cells remain in your body for months or years. If the real pathogen appears, these cells quickly produce antibodies and destroy infected cells before the infection takes hold. This is why vaccinated people often do not get sick or have milder symptoms - their immune system is already prepared.
Things to Know
- Some vaccines require boosters because immunity wanes over time or the pathogen mutates.
- Herd immunity occurs when enough people are vaccinated that the disease cannot spread easily.
- Vaccine side effects like soreness or mild fever are signs your immune system is responding.