1 rich Libsyn https://www.libsyn.com 90 600 A regression analysis conducted in Israel showed that a fourth dose appeared to increase the protection against severe illness relative to three doses that were administered more than 4 months earlier. Further studies are needed before applying this to a larger population.&amp;nbsp; Evidence Based Medicine presented by InpharmD™ http://inpharmd.libsyn.com/website <iframe title="Libsyn Player" style="border: none" src="//html5-player.libsyn.com/embed/episode/id/22957772/height/90/theme/custom/thumbnail/yes/direction/forward/render-playlist/no/custom-color/88AA3C/" height="90" width="600" scrolling="no" allowfullscreen webkitallowfullscreen mozallowfullscreen oallowfullscreen msallowfullscreen></iframe> https://assets.libsyn.com/secure/item/22957772