The Phacilitate Vaccine Forum in Washington DC (Jan 24-26, 2011) brought together vaccine stakeholders from industry, government and non-government organizations to discuss broad current issues covering the spectrum of vaccine policy, funding, research and clinical development, manufacturing, regulatory, and post marketing safety and surveillance. While the conference is held annually and the topics generally discussed reflect the emerging trends, case studies, and best practices of current interest to the vaccine industry, this year’s meeting had a new plenary session focusing on the intersection of diagnostics and vaccine development. The session was chaired by Dr. Una Ryan (President and CEO, Diagnostics for All) with the provocative title “How will diagnostics create new opportunitites for prophylactic and therapeutic vaccines?” and was followed by a panel discussion amongst industry leaders discussing the key diagnostic applications gaining interest in the vaccine industry. A common theme running through the session was the increasingly significant role of companion diagnostics and immune monitoring to facilitate and accelerate vaccine development. Indeed the recent examples from pneumococcal and meningococcal vaccine development where the developers and regulatory agencies have considered the use of diagnostic assays and immune markers to assess efficacy of the candidate vaccines in regards to licensure strategies for expanding the serotypes covered, can be considered as breakthrough events for the diagnostics developers. As such the meeting and the session was timely in presenting current progress and for soliciting a convergence of opinions amongst the vaccine industry and the regulatory agencies.