A new study by Novateur Ventures provides a comparative analysis of twelve Covid-19 vaccines that had initiated or announced the Phase III clinical trial stage by early November 2020. The study highlights the early successes, as well as the hurdles and barriers yet to be overcome for ending the global Covid-19 pandemic.
The study analysed: messenger RNA (Moderna and Pfizer/BioNtech), viral vector-based vaccines (Astra Zeneca/University of Oxford, CanSino Biologics, Gamaleya Research Institute, Johnson & Johnson/Janssen (J&J)), recombinant protein-based vaccines (Novavax and Medicago), and inactivated virus (three Chinese conglomerates and one Indian company).
The study, ‘Target Product Profile Analysis of Covid-19 Vaccines in Phase III Clinical Trials and Beyond: An Early 2021 Perspective’, appears in the Special Issue “Vaccines and Therapeutics against Coronaviruses” of the journal Viruses.
“The global concerted effort to develop vaccines to fight Covid-19 and deliver it to millions of citizens around the world in less than a year is an unprecedented feat in the history of medicine and a triumph for vaccine research and development,” said study co-author Ali Ardakani, Founder & Managing Director at Novateur Ventures. “Vaccination-mediated herd immunity will play a key role in helping us in returning to a world unhampered by restrictions and to global prosperity.”
Covid-19 vaccines belonging to four different platforms were analysed in five different categories using a “harmonised” target product profile (TPP) version of guidance from the World Health Organization, Coalition for Epidemic Preparedness Innovations (CEPI) and Center for Biologics Evaluation and Research (CBER).
With regards to vaccine efficacy, mRNA vaccines had the highest efficacy in the 95% range and across a spectrum of ages, followed by the protein subunit platform with an efficacy of just under 90% in the UK. The inactivated virus platform ranks lowest based on currently available variable data.
For the dosing regimen, all but two (CanSino and Johnson & Johnson/Janssen) of the 12 vaccines in the various platforms analysed in this study use a two-dose regimen.
mRNA vaccines rank lowest for logistics, with their burdensome cold-chain requirements.
The inactivated virus platform was the top performer for safety/reactogenicity. The viral vector platform scores below the other three platforms due to some lingering concerns related to paused trials and adverse events.
For target price/accessibility, the production of mRNA vaccines can be scaled-up at a reasonable pace, but they are currently among the most expensive Covid-19 vaccines; the viral vector vaccines are the cheapest to prepare. The inactivated virus vaccines are relatively easy to produce and are cheap if one considers Bharat Biotech’s COVAXIN. However, there are some indications that the pricing of the vaccines made in China are very high.
“Ten out of twelve vaccines we analysed have already received some form of authorisation for use in different countries in a period of less than a year. This is a remarkable achievement,” said study co-author Colin Funk, Scientific Lead at Novateur Ventures. “We hope that SARS-CoV-2 viral variants, emerging at an alarming rate in various countries, will not derail the successful vaccine efforts to date.”
The study has also identified three main barriers/hurdles for ending the global Covid-19 pandemic. Firstly, while we know that antibody levels induced by natural infection with SARS-CoV-2 last several months, we do not know if there will be a requirement for repeat vaccine dosing on an annual (or other timeframe) basis. If repeat booster doses are required, especially related to the viral vector platform, the question is whether antibodies will be directed to the vector and whether this will diminish vaccine efficacy. Secondly, determining an immunological correlate of protection against SARS-CoV-2 is an important objective that still has not been achieved and will be crucial in facilitating future Covid-19 vaccine development and licensing. Thirdly, public perception and compliance in vaccine administration are also very large hurdles to surmount to achieve herd immunity in some countries/populations. While not discussed in this review, this is a key factor.
Image credit: Ben White