4.2.3. Recombinant subunits

Recombinant subunit-based vaccines may prove to be significantly advantageous compared to other approaches currently being implemented for development of a dengue vaccine. First of all, the lack of a replicating virus helps to ensure the safety of the product by avoiding the possibility for inadequate attenuation or reversion in the context of live virus approaches, or inadequate inactivation in the context of killed virus vaccines. Furthermore, under a tetravalent formulation, the ability to induce a balanced immune response may be more easily manipulated through dose adjustments using recombinant subunits compared to four replicating viruses. Finally, in terms of yield and cost effectiveness, and since the dengue vaccine mainly targets developing areas, a high yielding, highly immunogenic, recombinant subunit could prove to be an attractive alternative to vaccines based on virus replication, (live attenuated or killed) where yields may be lower than required [23].

Recombinant subunit vaccines stand as one of the safest alternatives, as a means to bypass the issue of viral interference, offering the possibility to administer a tetravalent formulation on an accelerated schedule. An advantage of an accelerated schedule is that full protective immunity could be induced more quickly, thus avoiding the potential of exacerbated disease due to partial immunity during an extended immunization course. Among other advantages of an accelerated schedule are better general compliance, more suitability for travelers and military personnel, easier integration into existing immunization schedules, and the potential for use in an outbreak setting. A balanced tetravalent immune response may also be more readily accomplished through simple dose adjustments for each of the four recombinant proteins, in comparison to live virus vaccines where the interactions between viruses can be complex and unpredictable [24].
