241001_Immunizations+Part+1+S17+1553.pdf

Immunizations, Part 1 Session 17 Lisa Kronstad, Ph.D. [email protected] https://www.cdc.gov/vaccines/index.html October 1, 2024 Cholla D 1 Learning Objectives Describe the importance of vaccination for individual and public health Diag...

Immunizations, Part 1 Session 17 Lisa Kronstad, Ph.D. [email protected] https://www.cdc.gov/vaccines/index.html October 1, 2024 Cholla D 1 Learning Objectives Describe the importance of vaccination for individual and public health Diagram the mechanism of protection elicited by the smallpox vaccine Compare and contrast the two immunological approaches used to protect babies from Respiratory Syncytial virus Compare and contrast arti cial and natural passive vaccination including its role in protecting individuals early during a pandemic Describe the differences between a primary and secondary immune response including the properties of memory B and T cells Explain the immunological steps involved in developing a protective immune response to a conjugate vaccine 2 fi Lecture Outline Vaccine history and societal impac Passive vs. Active Immunization Principles Polysaccharide Conjugate Vaccines 3 t Vaccines are our proven best defense against pathogens Vaccination mobilizes the host immune system to prevent disease by triggering immune memor Vaccination helps break the chain the transmission Ability of a vaccination to interrupt future transmission depends on: Length of pathogen incubation period Whether pathogen has a US life expectancy dropped 1.5 years in 2020 systemic stage or remains localized to mucosa 4 y Vaccines stimulate a protective immune response Important to distinguish between protection from disease, i.e. clinically apparent illness, from protection from infection. It is possible to be infected sub-clinically (asymptomatic) for certain pathogens Vaccines DO NOT prevent infection, they reduce disease severity 5  Vaccine History Variolation - deliberate nasal inoculation with dried smallpox scabs from a mild case, practiced in China, 11th century ~2-3 fatality rate Variola major fatality rate: 35% Edward Jenner, 1796, rst to use "cowpox" to protect against smallpox 6 fi Smallpox Vaccine Principle Cowpox/Vaccinia virus used by Edward Jenner triggers production of antibodies that cross-react with Smallpox/Variola virus antigens Led to the eradication of Smallpox from humanity Saves ~5 million lives/year 7 https://ourworldindata.org/smallpox#:~:text=It%20is%20impossible%20to%20know,million%20lives%20have%20been%20saved. Vaccine hesitancy As soon as smallpox vaccine became available, concerns it would lead to the development of cow parts emerged. 8 Large-scale vaccination campaigns have been successful WHO estimates 2-3 million lives are saved each year by current immunization programs Vaccines are a major part of public health measures, however are often less available or even left effective in developing nations (e.g. rubella, measles, rotavirus) Vaccine inequality 9 Principles of Virology, ASM Press https://www.nature.com/articles/s41577-020-00479-7 Vaccine hesitancy can reduce vaccine program efficacy In some cases, medical exemptions to vaccinations are indicated (e.g. SCID for rotavirus vaccine, etc.) These generally should not exceed ~1% of the population, however often do 10 Lecture Outline Vaccine history and societal impact Passive vs. Active Immunizations Principles Polysaccharide Conjugate Vaccines 11 Passive vs. Active Immunization Passive Immunization Administer the products of the immune response (typically antibodies) Short-term protection due to degradation Active Vaccination Administer a modi ed form of the pathogen or material derived from it that induces immunity Longer-term protection 12 Principles of Virology, ASM Press fi : : Natural Passive Immunization IgG in maternal circulation is passively transmitted to the fetus in utero via placenta, IgG levels slowly decline after birth Vaccination of pregnant woman can confer protection to baby during the rst ~6 months of life 13 Principles of Virology, ASM Press fi Respiratory Syncytial Virus leads to severe respiratory illness Respiratory Syncytial Viru RSV can cause bronchiolitis or pneumoni Virtually all children become infected by age 2 years 1-2% need hospitalization and may require oxygen, intubation, and/or mechanical ventilation 14 https://www.cdc.gov/rsv/high-risk/infants-young-children.html a s Respiratory Syncytial Virus leads to severe respiratory illness 15 https://www.youtube.com/watch?v=egGUL7igwTQ Prevention of RSV disease Active Vaccine: NEW IN 2023: ABRYSVO Randomized, placebo-controlled Phase 3 trial of RSV recombinant prefusion F protein in the mom demonstrated ef cacy against lower respiratory tract illness in the baby Recommended for use during pregnancy; given during RSV season to at 32-36 weeks gestation https://www.nejm.org/doi/full/10.1056/NEJMoa2216480 fi ™ Artificial passive Immunization Passive Therapy with Convalescent serum A virologist infected himself with Lassa virus in the 1960's in the laboratory Transfused with plasma from a nurse who had survived Lassa fever Often rst therapy available during the emergence of a new pathogen Convalescent serum (high titer) is still indicated for certain COVID-19 patients 17 fi Convalescent Plasma and Monoclonal antibodies for COVID-19 treatment or prevention Plasma is the liquid part of blood that remains when cells are removed Monoclonal antibodies (antibodies against single epitopes) can block infection Used early during COVID-19 prior to emergence of resistant variants 18 Principles of Virology, ASM Press Prevention of RSV disease Arti cial Passive Immunity: NEW IN 2023: Nirsevima Approved for infants