As of the week ending 17 February 2018, the US Centers for Disease Control and Prevention (CDC) reported 97 influenza-related pediatric deaths for the 2017–2018 influenza season, an alarmingly high number compared with recent years.
These unsettling statistics reinforce the need to shift away from the traditional chicken egg-based approach of mass production of commercial influenza vaccines, which commonly induces a suboptimal immune response.
Instead, GlobalData believes vaccine manufacturers should embrace the modernisation of commercial mass production of seasonal influenza vaccines developed from cell and recombinant vaccine construction technologies. These technologies are capable of producing vaccines that are better designed for combatting circulating strains of the influenza virus.
A 2018 CDC report estimates a vaccine efficacy of 36% for the 2017–2018 influenza season, especially against the H3N2 influenza strain, which is a dominant circulating strain this season. The vaccine’s poor effectiveness can be primarily attributed to mismatches in antigenic structure between the strains contained in the vaccine and those in widespread circulation.
Inherent limitations associated with the egg-based vaccine manufacturing process undermine the potential antibody-antigen binding affinity needed to achieve consistently high vaccine efficacy from season to season. Specifically, hereditary constraints presented by the egg substrate increase the antigen differentiation between the vaccine being constructed via egg and the region of the virus surface protein antigen targeted by the vaccine. The end result is a decrease in binding affinity of the induced antibodies created from a mismatched vaccine.
In contrast, cell-based and recombinant vaccines are not similarly constrained in design because their vaccine propagation is not egg-based. Sequiris, a leading influenza vaccine maker, has received FDA approval for its quadrivalent influenza vaccine, Flucelvax, which is an all cell-based candidate vaccine virus (CVV) derived from mammalian cells. Cell-based and recombinant vaccine production not only allow for direct incorporation of sequenced circulating influenza viruses, but can also be completed more quickly than the egg-based approach. The real-time strain surveillance relationship of this technology can provide the most effective seasonal influenza vaccine.
In order to best facilitate this shift away from egg-based technology, governments must modernise their partnerships with vaccine manufacturers. Current surveillance by the World Health Organization (WHO) and other institutions revolves around the six–eight month egg-substrate vaccine timeline. Overall vaccine efficacy improves with the newer technologies if their quicker manufacturing times are combined with government-provided seed virus submissions from increased surveillance at the global level for mutations in the antigenic target of flu vaccines.
Given the public outcry from this year’s seasonal influenza outbreak, along with the national security implications of a future severely virulent influenza pandemic, GlobalData believes that the transition to non-egg vaccine mass production technologies should be expedited as long as newer technologies demonstrate reliability, safety, and increased average vaccine efficacy. Further improvement in vaccine efficacy can be gained if trials of universal influenza vaccines, such as Vaccitech’s INVICTUS Phase II conserved antigen region study, prove successful.
GlobalData (2018). Expert Insight: Severe Flu Season Could Lead to More Myocardial Infarctions, February 2018, GDHC1601EI
GlobalData (2018). Expert Insight: Amid the Worst Influenza Season in Recent Memory, Lupin Launches Its Tamiflu Generic in the US, February 2018, GDHC1598EI
GlobalData (2018). Expert Insight: Lower Flu Vaccine Uptake and Multiple Circulating Flu Strains May Be Causing High Flu Index in Texas Cities, February 2018, GDHC1587EI
GlobalData (2018). Expert Insight: Is It Time for Europe to Embrace the Quadrivalent Influenza Vaccine?, January 2018, GDHC1554EI
GlobalData (2016). Pharma Point: Seasonal Influenza Vaccines – Global Drug Forecast and Market Analysis to 2025, October 2016, GDHC130PIDR