ICSE Class 8 Answered

Four types of vaccines prepared are as follows:

• Live virus vaccines: They use the weakened or attenuated form of the virus. The measles, mumps, and rubella (MMR) vaccine and the varicella (chickenpox) vaccine are examples.
• Killed (inactivated) vaccines are made from a protein or other small pieces taken from a virus or bacteria. The whooping cough (pertussis) vaccine is an example.
• Toxoid vaccines contain a toxin or chemical made by the bacteria or virus. They make us immune to the harmful effects of the infection, instead of to the infection itself. Examples are the diphtheria and tetanus vaccines.
• Biosynthetic vaccines contain manmade substances that are very similar to pieces of the virus or bacteria. The Hepatitis B vaccine is an example.