Making Vaccines

Effective Vaccines Have low levels of side effects or toxicity. Protect against exposure to natural, or wild forms of the pathogen. Should stimulate both an antibody (B-cell) response and a cell mediated (T-cell) response. Have long term, lasting effects that produce immunological memory. Should not require numerous doses or boosters Are inexpensive, have a long shelf life and are easy to administer.

Routes of Administration The majority of vaccines are administered by injection –Subcutaneous –Intramuscular –Intradermal Oral vaccines are available for only a few diseases

Types of Vaccines Killed whole cells or inactivated viruses –Even though they are harmless, they still contain recognizable antigens on their surface –Because the microbe does not multiply, larger doses and more boosters are required. Live, attenuated (weakened) cells or viruses –Vaccines are longer-lasting and require fewer boosters –However, the disease agent could mutate back to pathogenic strain

Types of Vaccines Toxoid vaccines –A purified toxin produced by the antigen is used to elicit immune response. Genetically engineered microbes or microbial antigens –Genes for microbial antigens are inserted into a plasmid vector and are cloned in appropriate hosts. –The resultant protein product is used to provoke immune system. DNA vaccines –These vaccines contain all or part of the pathogen DNA, which is used to “infect” a recipient’s cells.

Herd Immunity More individuals that are immune decreases the incidence of the disease and the occurrence of the pathogen. With greater numbers immunized, it is less likely that an unimmunized person will encounter the pathogen. Mass vaccination confers indirect protection for those who do not receive the vaccine resulting in “herd immunity”.