Target Product Profile Analysis of COVID-19 Vaccines in Phase III Clinical Trials and Beyond: An Early 2021 Perspective

Abstract

The coronavirus SARS-CoV-2, which causes Coronavirus disease 2019 (COVID-19), has infected more than 100 million people globally and caused over 2.5 million deaths in just over one year since its discovery in Wuhan, China in December 2019. The pandemic has evoked widespread collateral damage to societies and economies, and has destabilized mental health and well-being. Early in 2020, unprecedented efforts went into the development of vaccines that generate effective antibodies to the SARS-CoV-2 virus. Teams developing twelve candidate vaccines, based on four platforms (messenger RNA, non-replicating viral vector, protein/virus-like particle, and inactivated virus) had initiated or announced the Phase III clinical trial stage by early November 2020, with several having received emergency use authorization in less than a year. Vaccine rollout has proceeded around the globe. Previously, we and others had proposed a target product profile (TPP) for ideal/optimal and acceptable/minimal COVID-19 vaccines. How well do these candidate vaccines stack up to a harmonized TPP? Here, we perform a comparative analysis in several categories of these candidate vaccines based on the latest available trial data and highlight the early successes as well as the hurdles and barriers yet to be overcome for ending the global COVID-19 pandemic.

Keywords: COVID-19; SARS-CoV-2; clinical trial; coronavirus; immune response; public health; target product profile; vaccine.

Figure 1

The twelve SARS-CoV-2 vaccine candidates reaching/announcing Phase III clinical trials by mid-November 2020. Shown in pie-chart configuration are the companies responsible for the development of the vaccines as well as their reported efficacy in Phase III trials. *, efficacy not yet available. Due to variability in reporting criteria for cases of COVID-19, efficacy results may not be directly comparable.

Figure 2

Ranking of four vaccine platforms according to criteria for harmonized target product profile as mentioned in the text.

Figure 3

Manufacturing process of vaccines from four platforms covered in this review. The mRNA platform is represented by the Pfizer vaccine. The vaccine development process for the viral vector and inactivated whole virus platforms process are generic, while the protein/VLP platform is represented by the vaccine from Medicago. Timelines are not to scale.