There is a lot of interest and urgency to develop a SARS-Cov 2 (COVID-19) vaccine. The initial optimism of politicians to develop and deploy a vaccine in 2020 has been tempered by healthcare authorities and vaccine companies. This article will discuss realistic prospects for vaccine development, regulatory approval and timelines.

Developing a vaccine is not a straightforward task. It is still based on a process of trial and error (informed by experience), with no guarantee of success. The vaccine must be backed by evidence of safety and efficacy before it can be deployed, to minimize risk that it may be ineffective or harmful. The development costs and risks are assumed by the vaccine manufacturer as part of its cost-benefit business analysis. The company goal is that revenue from one successful treatment will be able to pay for that treatment as well as failed attempts. This is why a vaccine developer needs to own IP arising from its R&D. If a publicly funded agency assists a company with vaccine development, the agency may get rights in an invention through law or a contract. For a global pandemic, it is likely that a vaccine IP owner will license other companies to make the vaccine.

Vaccine Development

The current pathway for human vaccine development is a very complex, highly risky, and costly process that includes research, proof of concept, clinical development, process development, and assay development. This is followed by regulatory approval, manufacturing and distribution. The risk is high since most vaccine candidates fail in preclinical or late stage clinical development. Vaccines have to be safe and effective.

The preclinical proof of concept phase usually lasts many years depending on the nature of the disease and available animal models (2-4 years). Clinical development is also a lengthy process and can take 6-10 years on average. The manufacturing processes are typically developed once a final formulation is identified. Regulatory approval can take up to 1-2 years before the vaccines is approved for use. So added together a standard development time is around 10 to 15 years before the vaccine is in use. In a time of urgent need of a vaccine, such as what we have with the current COVID-19 pandemic, the typical timelines need to be drastically reduced to urgently provide a product to the world.

There is currently no approved human commercial vaccine against any coronavirus. There are livestock coronavirus vaccines, such as Bovilis. In the case of SARS-Cov 2- (COVID-19) the use of preexisting knowledge from a similar infectious agent such as the 2002-2003 SARS epidemic and the more recent 2015 MERS outbreak will also help reduce the preclinical steps of a candidate vaccine timeline. These coronavirus epidemics petered out before a vaccine was developed.

Existing Vaccine Technologies

Further reduction of development timelines could be gained by utilizing existing technologies for vaccine development. The advantage of these approaches is a proven track record of prior safe and effective vaccines. Compatible equipment and facilities are already in place and approved by regulators. Some examples of these technologies are use of:

  • Existing animal cells to grow and produce the virus;
  • Plant or microbial cell to produce any native or recombinant viral protein antigen;
  • Existing virus-like particle (VLP) technologies;
  • Existing viral vectors – replicating and non-replicating, chimeric vectors, for safe growth of attenuated viruses;
  • Naked or formulated nucleic acid vectors such as DNA or mRNA; and
  • Peptide/protein subunit approaches.

Very new vaccine technologies are also under development, but any new technology would have to offer a significant time and/or efficacy advantage over existing technologies as well as demonstrating safety. Further to the technologies to produce the antigen(s) needed to provide immunity to SARS Cov-2, there will also be efforts to enhance the immune response generated through the use of different adjuvants. This strategy was utilized during the 2009-10 H1N1 swine-flu Pandemic with GSK's AS03 adjuvant. There are also interesting therapeutic vaccine options in development utilizing a Monoclonal Antibody or a Fab fragment, which could also be manufactured using pre-existing technologies.

These very powerful technologies are very likely to produce a vaccine. It is also very likely that the first vaccines that show promise may not result in the ultimate protection, leading to a second generation shortly after the first. We may also find that we are in the situation of having several different types of vaccines launched around the world.

There is cautious optimism that these very powerful technologies are likely to produce a vaccine. In Part II of this article, we will review the steps to obtain approval and launch a vaccine.

Originally published 07 July, 2020

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