What Is A Vaccine? Do Vaccines Work?

VACCINE What is a vaccine?Do vaccines work?A vaccine is a biological preparation that provides active acquired immunity to a particular infectious disease. A vaccine typically contains an agent that resembles a disease-causing microorganism and is often made from weakened or killed forms of the microbe, its toxins, or one of its surface proteins. A vaccine stimulates a person's immune system to produce immunity to a specific disease, protecting the person from that disease. They are usually administered through needle injections, but can also be administered by mouth or sprayed into the nose. Immunization began with smallpox. It was only based on the observation that immunity could be conferred by rubbing smallpox scabs against the skin, which usually resulted in a mild case of the disease. Inoculation of individuals with the disease smallpox was done in China and some parts of Africa. Later on, inoculation was started in Britain and some parts of America in the early 18th century. These inoculations lead to many deaths resulting in many controversies about the risks of the procedure and it created ways in search of a better way of obtaining vaccines. The search was later focused on the disease