27. Vaccines 101

Lecture Summary Vaccines are biological tools used to educate our acquired immune system. They have allowed for the prevention of numerous infectious diseases within populations throughout the world. Additionally, they have made it possible to eradicate diseases on a global scale. I believe that vaccines are the greatest clinical medicine advancement ever made. We depend on these biological tools for a modern life. Sadly, they are currently under attack, mostly from loud voices making scientifically baseless claims. Currently available vaccines prevent millions of deaths and hundreds of millions from suffering every single year. Key Points - In 2020, there are vaccines available for the prevention of 27 infectious diseases in the United States. Most are highly efficacious. - Worldwide there are vaccines available for the prevention of an additional 5 or so diseases. Namely malaria, ebola, dengue, tick-borne encephalitis, and hepatitis E. - Vaccines against at least 30 additional diseases are currently in the pipeline for development. - While some vaccines (eg Anthrax) can be dangerous and have common side effects, all vaccines currently recommended for routine use in children and adults are exceptionally safe. - Vaccines come in different forms. These include inactivated whole organisms, live-attenuated, subunit (single or multiple antigens), subunit-conjugated, toxoid, heterotypic, mRNA, and other experimental designs. - Vaccines prevent infection in individuals. When enough people in a population are vaccinated, communicable diseases cannot effectively spread, thereby offering what is called “herd immunity”. - There are very few contraindications to routine vaccinations. - A history of severe allergic reaction to any vaccine or component within a vaccine is the most common (exceedingly rare) contraindication. - Live attenuated vaccines are contraindicated in pregnancy and certain types of immunodeficiency. - Titers are a good way to check for immunity if vaccination status is unknown. - Everybody needs to get back on board with vaccines. They are essential for modern life and will be needed to save us from current and future pandemics. References - CDC. Vaccines schedules: https://www.cdc.gov/vaccines/schedules/hcp/imz/child-adolescent.html; - CDC. Vaccine Information Statements. https://www.cdc.gov/vaccines/hcp/vis/index.html - CDC. Diarrhea global killer. https://www.cdc.gov/healthywater/pdf/global/programs/Globaldiarrhea508c.pdf - WHO. Vaccine recommendations by country: https://apps.who.int/immunization_monitoring/globalsummary - WHO. Individual vaccine pages. Eg. https://www.who.int/news-room/q-a-detail/poliomyelitis-vaccine-derived-polio - Wikipedia.org – Vaccines, pages for diseases prevented by vaccines, pages for individual vaccines. - Uptodate.com – Childhood vaccines, Adult vaccines, Pages for individual vaccines.