Early vaccine availability represents an important public health advance for the control of pandemic influenza

Abstract

Background: Traditional processes for the production of pandemic influenza vaccines are not capable of producing a vaccine that could be deployed sooner than 5-6 months after strain identification. Plant-based vaccine technologies are of public health interest because they represent an opportunity to begin vaccinating earlier. Methods: We used an age- and risk- structured disease transmission model for Canada to evaluate the potential impact of a plant-produced vaccine available for rapid deployment (within 1-3 months) compared to an egg-based vaccine timeline. Results: We found that in the case of a mildly transmissible virus (R0 = 1.3), depending on the amount of plant-based vaccine produced per week, severe clinical outcomes could be decreased by 60-100 % if vaccine was available within 3 months of strain identification. However, in the case of a highly transmissible virus (R0 = 2.0), a delay of 3 months does not change clinical outcomes regardless of the level of weekly vaccine availability. If transmissibility is high, the only strategy that can impact clinical outcomes occurs if vaccine production is high and available within 2 months. Conclusions: Pandemic influenza vaccines produced by plants, change the timeline of pandemic vaccine availability in a way that could significantly mitigate the impact of the next influenza pandemic.