Introduction Immunization allows for individuals to be protected against disease Immunity can be conferred in two ways including active immunity that is maintained by the immune system passive immunity that is given transiently from outside Vaccinations are a major source of conferring immunity outside normal infection and include viral vaccines divided into killed vaccines live attenuated vaccines bacterial vaccines Often vaccinations require an adjuvent that enhances the immune reaction against the vaccine provided increases the development of memory to non inflammatory antigens can be of several types including aluminum potassium sulfate muramyl dipeptide LPS/polyribonucleotides Though vaccines are generally safe, contraindications to their use include people with egg allergies who should avoid yellow fever vaccine and other vaccines made in eggs pregnant women who should avoid rubella vaccines immunocompromised individuals who should avoid all live vaccines Active vs Passive Immunity Immunity can be either active or passive with several notable differences Differences Between Active and Passive Immunity Feature Passive Active Acquisition method Receiving preformed antibodies Exposure to infection or to foreign antigens Examples Maternal IgG crossing placenta Babies getting IgA in breast milk Administration of antitoxin Infection with the specific pathogen Administration of a vaccine Onset Immediate upon administration Slow to allow for development of full immune response Duration Very short with a half life between two weeks and four weeks Long or even lifetime Due to generation of memory Viral Vaccines Viral vaccines can either be live attenuated or killed with several notable differences Differences between Live and Killed Vaccines Feature Live Killed Production method Design a nonpathogenic version of a virus that can still grow transiently in the host Inactive pathogen or pathogen antigens by treatment with heat or chemicals Pros Induce both cellular and humoral responsesnduces lifelong immunity (usually) Induces lifelong immunity (usually) Safer than live vaccines because they cannot revert to pathogenic state Cons Cannot give to immunocompromised patients Small chance of reverting to pathogenic state Weaker response (usually only humoral) May require booster shots Examples Everything else MMR VZV Polio (Sabin) Etc Rest In Peace Always Rabies Influenza Polio (Salk) HepatitisA Bacterial Vaccination Bacterial vaccination involves administration of characteristic protein which can be inactivated toxin produced by pathogen called a toxoid coat protein that surrounds the pathogen called a capsule other important proteins that are conserved by the pathogen Select examples of vaccines against pathogenic bacteria include DTaP that is composed of C. diptheriae toxoid C. tetani toxoid B. pertussis toxoid H. influenzae capsular type B S. pneumoniae that comes in two forms including a pediatric version with 7 capsule types think: a 7 year old gets PCV an adult version with 23 capsular types N. meningitidis with 4 capsular proteins Parenterally delivered vaccines are not effective against mucosal bacteria due to inferior secretory IgA response Examples of mucosal bacteria E. coli V. cholerae Orally delivered vaccines are allow direct antigen contact with mucosa, generating a strong secretory IgA response