Despite the availability of flu vaccines for decades, influenza is still an important disease in both developing and developed countries with 500,000 casualties annually and many more people affected. From a global health perspective, the lack of effectivity, availability, affordability, and accessibility of flu vaccines significantly limits our ability to respond to the seasonal flu every year and in the event of a pandemic.
Currently, a low vaccine effectivity of 40% implies that 60% of vaccinated people are not sufficiently protected, with low confidence further contributing to limited uptake/immunization. Within INDIGO, public and private R&D organizations in India, EU and US collaborate on the development of two novel influenza vaccine concepts that meet the requirements of global vaccination, aiming to achieve less non-responders, lower costs, and better accessibility:
1) TETRA-LITE, an affordable seasonal flu vaccine with high efficacy at low cost and possible exploitation within a few years after completion of the project; and
2) PANDEMIC-PLUS, a further improved flu vaccine concept dealing with technological shortcomings and challenges of wide-spread use.
The first approach combines a low dose of a commercial, inactivated, seasonal flu vaccine with a novel, potent adjuvant CMS (LVA). The adjuvant was tested in humans for the first time within the INDIGO project and was proven safe and well tolerated. When combined with just one-fifth of the standard flu vaccine dose, CMS induced immune responses comparable to full-dose vaccines without adjuvants. This suggests significant potential for antigen sparing, which could lead to more cost-effective vaccine production.
The second approach builds on three innovations: 1) a novel recombinant HA with increased immunogenicity, 2) novel adjuvants, and 3) an easy, needle-free delivery by intradermal patches.
Contra-productive parts of HA have been removed to increase the immunogenicity of influenza epitopes. The adjuvants further stimulate protective immunity and immunological memory. The use of intradermal patches opens possibilities for self-administration, which will improve vaccine uptake in developing as well as developed countries. These plans differ in complexity and timelines but can all contribute to delivering next-generation flu vaccines for the globe.
