There's a Major Global Shortage of the Letters 'A', 'B', and 'O' By Notable Life By Notable LifeView Author|August 17, 2016|Health + Wellness,View Health + Wellness LifeView Life The letters A, B and O are disappearing from familiar landmarks and logos around the world. As part of the #MissingType campaign by NHS Blood and Transplant and London-based PR agency Engine Group, the three letters that signify blood types are... View this article.