Why are vaccines so hard to make? The FDA approved two mRNA vaccines for COVID-19, but it was a challenge to make this type of vaccine work. In fact, it took decades of research to get us to the point where scientists could make those vaccines as quickly as they did! Learn all about it with Hank in this new episode of SciShow! 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, Jb Taishoff, Bd_Tmprd, Harrison Mills, Jeffrey Mckishen, James Knight, Christoph Schwanke, Jacob, Matt Curls, Sam Buck, Christopher R Boucher, Eric Jensen, Lehel Kovacs, Adam Brainard, Greg, Ash, 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.frontiersin.org/articles/10.3389/fimmu.2019.00594/full#h5 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6936610/ https://www.nature.com/articles/s41541-020-0159-8 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3478238/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3597572/ https://academic.oup.com/pcp/article-abstract/27/4/619/1850703 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5964141/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6631684/ https://www.frontiersin.org/articles/10.3389/fimmu.2018.01012/full https://pubmed.ncbi.nlm.nih.gov/22549871/ https://www.sciencedirect.com/science/article/pii/S1074761305002116 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5987916/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2835112/ https://clincancerres.aacrjournals.org/content/13/2/540 https://www.mdpi.com/1420-3049/25/1/204/htm https://www.biorxiv.org/content/10.1101/2020.09.08.280818v1.abstract https://www.nejm.org/doi/full/10.1056/NEJMoa2028436 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4798869/ https://www.nature.com/articles/274923a0 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5439223/ https://www.cell.com/cell-host-microbe/pdf/S1931-3128(20)30248-1.pdf https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6901985/ https://www.nature.com/articles/nrd.2017.243 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7554980/ Images: https://commons.wikimedia.org/wiki/File:Moderna_COVID-19_vaccine.jpg https://commons.wikimedia.org/wiki/File:PDB_1ucg_EBI.jpg https://commons.wikimedia.org/wiki/File:PDB_1bol_EBI.jpg https://commons.wikimedia.org/wiki/File:PDB_1ucd_EBI.jpg https://commons.wikimedia.org/wiki/File:PDB_2rln_EBI.jpg https://commons.wikimedia.org/wiki/File:MRNA_structure.svg https://commons.wikimedia.org/wiki/File:SolidLipidNanoparticle.jpg https://commons.wikimedia.org/wiki/File:SARS_virion.gif https://phil.cdc.gov/Details.aspx?pid=15906 https://www.thingiverse.com/thing:3146686