The VTEUs played a role in testing acellular pertussis vaccines in the late 1980s, when pressure from activist groups led to congressional demands for a safer alternative to whole-cell pertussis vaccines, and again in the 1990s, when the United States initiated the transition from oral to inactivated poliovirus vaccines. In each case, the FDA has been in the loop to ensure that adequate testing takes place. And importantly, the government also has promised to purchase a certain number of vaccine doses from the companies, thereby further ensuring economic feasibility.
Thus far the VTEUs have been brought into use on a case-by-case basis. I think their use should become a routine mechanism in shortage situations. For example, GlaxoSmithKline (GSK) currently has another Hib vaccine on the market in Europe called Hiberix. It's virtually identical to Sanofi Pasteur's ACTHib, yet it is not licensed in the United States. Why? My guess is that GSK has determined that the large investment it would take to satisfy FDA's stringent safety and immunogenicity requirements wouldn't be worthwhile simply to bring a third Hib vaccine to market.
In the interest of public health, I believe the FDA should ask the VTEUs to conduct those studies in order to bring Hiberix here to help alleviate our current Hib vaccine shortage. The same goes for an MMRV vaccine that GSK also makes for the European market. Both are “mature” vaccines that can't command the kind of prices that the newer vaccines like Prevnar and Menactra can. I believe these are cases where the government must step in and help. We should not have to rely on a single source for these products. It's unsafe for the public.