How has the measles vaccine prevented diesease?

Answer 1

Measles vaccine prevents from measles and is administered to children of 18 months with a second dose before age of 4 or 5 years.

Vaccine of measles contain alive viruses (called antigens). The alive antigen can reproduce inside the human body but they do not damage host because they are weakened in laboratory to the point where they are still alive and able to reproduce but can not cause serious illness.

When this vaccine is injected into the human body, the T cells of lymphocytes (White blood cells) detect the type of viruses in it. Then B cells of lymphocytes produce antibodies against these viruses. The viruses reproduce inside human body therefore the lymphocytes produce more antibodies against this specific type of viruses. Antibodies bind to the viruses, stop their activity and destroy them.

Now the viruses of vaccine have been destroyed but the antibodies against them are still present and they prevent the actual viruses (harmful) of measles to cause illness.

The person who has once caught measles also has the antibodies against measles viruses after the actual viruses entered the body and caused illness. Therefore the patient will recover within a week without using the vaccine.This person can not get measles again in life because the antibodies against measeles are already produced for prevntion by catching measles once. These antibodies are memory cell for this specific type of viruses.

The vaccine of measles does not cure but it is used for prevention because it helps in production of antibodies against measles without causing illness.