there are two major categories of vaccines. the first category of vaccine is made from live viruses that have been "attenuated" or weakened so that they usually do not cause the disease. in some cases the vaccine itself does cause the disease. usually the disease caused by the vaccine is milder than the natural disease. the second category of vaccine inactivated vaccine is produced by growing the bacterium or virus in culture and then inactivating it (killing it) by using heat or chemicals. these vaccines cannot cause the disease but allow the body to develop immunity. while these vaccines are safer they do not produce protection as good as that from the live vaccines. these vaccines require multiple doses and often require periodic supplementation. live attenuated vaccines measles mumps rubella vaccinia varicella zoster yellow fever rotavirus intranasal influenza oral polio bcg oral typhoid inactivated (killed) vaccines diphtheria tetanus polio shot hepatitis a hepatitis b rabies influenza shot pertussis acellular pertussis human papillomavirus anthrax typhoid cholera pneumococcal meningococcal salmonella haemophilus influenza type b
are there different types of vaccines?