Britannica Sources used in this answer

How do vaccination and previous infection protect people from measles?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Know the investigations of researchers using genomic information to reconstruct the cause and transmission routes of the bubonic plague and the Black Death — epidemiology Researchers using genomic information to trace the transmission routes in past epidemics of plague.

Both vaccination and previous infection protect individuals from measles by stimulating the immune system to develop immunologic memory, a process grounded in the principles of specificity and memory.12

When a person is infected with the measles virus, their immune system produces antibodies and specialized cells that specifically recognize and neutralize the pathogen. Once the body has successfully fought off the virus, it "remembers" the specific antigen for years or even a lifetime, allowing for a faster and stronger response if the individual is exposed to the virus again.123

Vaccination mimics this natural process safely. By introducing a live attenuated form of the virus, the vaccine stimulates the immune system to produce antibodies and lymphocytes without causing the disease itself. This ensures that the body is prepared to defend against the virus before actual exposure occurs. Through this active immunization, both natural recovery and vaccination provide long-lasting protection, which is essential for maintaining individual health and contributing to herd immunity within a population.4125