Preventing Measles


There is no cure for measles, so the best approach is to prevent people from getting infected, by vaccinating them before they are exposed to the virus.

Vaccines are made from the kind of germ they are designed to protect against. Some vaccinations are made from inactivated or killed viruses or bacteria. Others are made from certain products or parts of the invader, but not the whole disease germ. Many effective vaccinations are made with live viruses or bacteria that are particularly weakened so that they can not cause disease in the body. Scientists have found, for example, that when measles viruses are grown for a long time in animal cells in a test tube, they gradually change and eventually become less capable to spread in people and cause illness. Such weakened strains of germs are referred as to attenuated.

How vaccines work

Vaccines trick the body into building up defenses against a particular disease-causing virus or other body invader without actually exposing it to the danger of disease. The vaccine contains look-alike chemicals that are similar to parts or products of disease germs. The immune system recognizes these chemicals as "foreign" (things that do not normally belong in the body), and therefore produces antibodies against them. These antibodies can also match up with parts of the real disease germs.

So if measles viruses, for example, enter the body of a person who has received injections of measles vaccine, cells coated with antibodies floating in the person's blood quickly recognize the invader and neutralize it. These cells remember the antigen from the vaccine and mass-produce measles antibodies, which continue to attack the invading viruses and kill them before the can multiply to dangerous levels.