Vaccines PDF

Vaccines Prof. L.J. Egan VACCINES History of vaccination: Jenner and smallpox Milkmaids seldom got smallpox: why? Milkmaids often got cowpox: a mild disease similar to smallpox Eradication of smallpox     Recovery: 70% Mortality: 30% No reported cases in community since 1977 Attributed to worldw...

Vaccines Prof. L.J. Egan VACCINES History of vaccination: Jenner and smallpox Milkmaids seldom got smallpox: why? Milkmaids often got cowpox: a mild disease similar to smallpox Eradication of smallpox     Recovery: 70% Mortality: 30% No reported cases in community since 1977 Attributed to worldwide uptake of vaccine Last case of Smallpox at University of Birmingham  Laboratory worker in University of Birmingham 1978    Contracted smallpox and died 2 days later Led to drastic improvements in laboratory handling of dangerous pathogens Only two laboratories in the world now hold smallpox Vaccines harness the adaptive immune system Successful vaccination campaigns. Viruses are traditionally attenuated by selecting for growth in nonhuman cells Attenuation can be achieved more rapidly and reliably with recombinant DNA techniques. Live attenuated vaccines eg Measles mumps rubella Inactivated vaccines eg Hepatitis A Subunit/conjugated vaccines eg Hepatitis B How do vaccines work?   Antigen provides specificity of response to adaptive immunity Adjuvant provides innate immune activity to boost adaptive immunity Vaccination & subsequent infection Antibody response to vaccines and infection Herd Immunity    Indirect protection against disease that results from a sufficient number of individuals in a community having immunity to that disease. With enough immune individuals, the transmission of a disease can be reduced, thus limiting the potential for any one individual to be exposed to it. Herd immunity does not apply to diseases, such as tetanus, that are not spread via person-to-person contact. Herd Immunity Unvaccinated Successful herd immunity Unsuccessful herd immunity Childhood Immunizations in Ireland Boosters needed Reasons for inability to develop effective vaccines: HIV     Lack of natural immunity to HIV Variability of HIV types Lack of correlates of protective immunity Lack of an animal model that reliably predicts vaccine efficacy in humans Passive immunization    Vaccines stimulate active immunization Administration of antibodies from an exposed donor specific to the infectious agent provides passive immunity Examples:    Diptheria antitoxin (horse) Hepatitis A RSV (monoclonal antibody) Human papilloma virus vaccine: protection against certain cancer     HPV is a common STI Infection at sexual debut Most infected persons clear HPV infection Chronic HPV16 infection causes certain cancers:     Cervical Anal Penile Head and neck Harald zur Hausen Nobel Prize for Medicine 2008 Gardasil: HPV vaccine effectiveness     Universal vaccination for teenage girls 2010 Uptake variable Anti-Vaxx movement Role out universal programme for boys 2019 Introduced 2010 False link between MMR vaccine and autism     Claimed link between MMR vaccine and autism Results not reproducible Scientific misconduct Struck off register by UK General Medical Council Dr Andrew Wakefield Anti-vax campaigns arguments     Trust: emphasizing suspicion about the scientific community, concerns about personal liberty Alternatives: focusing on chemicals in vaccines, use of homeopathic remedies over vaccination Safety: perceived risks and concerns about vaccination being immoral Conspiracy: that government "hides" information that anti-vaccination groups believe to be facts How to counter anti-vax movement Questions?