Thanks to KiwiCo for supporting this episode of SciShow! Head to https://www.kiwico.com/mlp/SciShow50 to get 50% off your first month of any crate. Vaccines teach your immune system to recognize pathogens, but sometimes your body needs a bit of a reminder. Hosted by: Hank Green SciShow has a spinoff podcast! It's called SciShow Tangents. Check it out at http://www.scishowtangents.org/ ---------- Support SciShow by becoming a patron on Patreon: https://www.patreon.com/scishow ---------- Huge thanks go to the following Patreon supporters for helping us keep SciShow free for everyone forever: Silas Emrys, Charles Copley, Drew Hart, Jeffrey Mckishen, James Knight, Christoph Schwanke, Jacob, Matt Curls, Christopher R Boucher, Eric Jensen, Lehel Kovacs, Adam Brainard, Greg, GrowingViolet, Ash, Laura Sanborn, Sam Lutfi, Piya Shedden, KatieMarie Magnone, Scott Satovsky Jr, charles george, Alex Hackman, Chris Peters, Kevin Bealer ---------- Looking for SciShow elsewhere on the internet? Facebook: http://www.facebook.com/scishow Twitter: http://www.twitter.com/scishow Tumblr: http://scishow.tumblr.com/ Instagram: http://instagram.com/thescishow ---------- Sources: https://www.cdc.gov/vaccines/vpd/vaccines-diseases.html https://cmr.asm.org/content/32/2/e00084-18 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4962729/ https://pedsinreview.aappublications.org/content/40/1/26 https://stm.sciencemag.org/content/10/433/eaao5945 https://www.cdc.gov/pertussis/about/faqs.html https://www.nature.com/articles/s41577-020-00479-7 https://www.cell.com/cell-host-microbe/fulltext/S1931-3128(11)00128-4 https://link.springer.com/protocol/10.1007/978-1-4939-7762-8_5 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5123673/ https://www.pnas.org/content/117/30/17720 https://www.frontiersin.org/articles/10.3389/fimmu.2019.02247/full https://www.nature.com/articles/s41577-020-00434-6 https://www.immunize.org/askexperts/experts_mmr.asp#general https://www.cdc.gov/measles/about/faqs.html https://www1.health.gov.au/internet/main/publishing.nsf/Content/cda-cdi3301c.htm https://www.liebertpub.com/doi/full/10.1089/vim.2017.0143 https://www.cdc.gov/vaccines/schedules/hcp/imz/adult.html https://www.cdc.gov/vaccines/schedules/hcp/imz/child-adolescent.html https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4848602/ https://www.who.int/biologicals/vaccines/pertussis/en/ https://pediatrics.aappublications.org/content/144/1/e20183466 https://www.cdc.gov/vaccines/vpd/pertussis/recs-summary.html https://www.healthaffairs.org/doi/10.1377/hlthaff.2014.1199 https://www.cdc.gov/vaccines/covid-19/info-by-product/clinical-considerations.html https://investors.modernatx.com/static-files/d427592c-dab4-4715-a568-31207d9832ab https://www.cnbc.com/2021/01/14/moderna-looks-to-test-covid-19-booster-shots-a-year-after-initial-vaccination.html https://investors.modernatx.com/news-releases/news-release-details/moderna-covid-19-vaccine-retains-neutralizing-activity-against https://www.bmj.com/content/372/bmj.n232 Image Sources: https://www.istockphoto.com/photo/talking-about-patients-diagnosis-gm1283161265-380667753 https://www.istockphoto.com/photo/vaccination-healthcare-concept-hands-of-doctor-or-nurse-in-medical-gloves-injecting-gm1126118968-296314868 https://commons.wikimedia.org/wiki/File:Hepatitis_A_virus_01.jpg https://commons.wikimedia.org/wiki/File:Clostridium_tetani.jpg https://commons.wikimedia.org/wiki/File:Papilloma_Virus_(HPV)_EM_(new_version).jpg https://www.istockphoto.com/vector/immune-system-gm480156534-68280651 https://www.istockphoto.com/vector/vaccine-shot-injection-syringe-background-gm1289926784-385462381 https://commons.wikimedia.org/wiki/File:Measles_virus.JPG https://commons.wikimedia.org/wiki/File:Bordetella_pertussis.jpg https://www.istockphoto.com/photo/vaccination-to-a-child-gm1057582308-282629269 https://www.istockphoto.com/vector/vaccine-illustration-with-people-gm1287036245-383352728 https://www.istockphoto.com/vector/syringe-injection-icon-gm1209677318-350132817 https://www.istockphoto.com/photo/medical-home-visit-gm1282928823-380516138