The authentic live influenza cell-based vaccine and its imitations

The problem of transferring the technology of influenza vaccine production from developing chicken embryos to mammalian cell culture has been discussed for many years. The technologies being developed for the production of cell-based vaccines rely on two promising substrates — continuous Vero and MDCK cell lines, which effectively support the replication of influenza viruses of various subtypes. In 2018, the WHO issued the first recommendations on the composition of influenza vaccines produced in mammalian cell culture. Since then, the WHO has issued separate recommendations for egg-based and cell-based vaccines for the upcoming epidemic season. The cell-based influenza vaccine has a number of undeniable advantages: the possibility of mass production of the vaccine preparation, which is particularly important during a pandemic, and the lack of an allergenic factor such as egg white in the vaccine. It is also believed that conventional egg-based influenza vaccines may be less effective than cell-based vaccines due to acquired adaptive “egg” mutations. All of the above suggests that the development of appropriate cellular systems highly sensitive to currently circulating influenza virus strains and capable of ensuring the accumulation of large amounts of viral biomass is of considerable practical interest. If we compare two conventional influenza vaccines, inactivated and live, the latter has a number of advantages, such as a non-injection route of administration, a broader spectrum of protection, high yield, low cost, simplicity of the production process, etc. If we add to this a new — cellular — substrate for the production and accumulation of viral biomass, we have the prospect of developing a vaccine preparation with virtually no drawbacks. Despite the obvious advantages of cell culture as a substrate for influenza vaccine production, some influenza vaccines, including live attenuated cold-adapted influenza vaccine, are still produced in the developing chicken embryos. Therefore, we considered it appropriate to collect the available scientific literature on the development of approaches for the production of a live influenza cold-adapted cell-based vaccine.