COVID-19 Vaccine Development: The Jump to Lightspeed | Modis Belgium

COVID-19 Vaccine Development: The Jump to Lightspeed

Morgane Florens Posted 16 February 2021
Since the World Health Organization declaration of the Covid-19 pandemic in March 2020, there has been an unprecedented race to develop a vaccine that could free the world from this deadly disease. However, given the extremely controlled and long process usually required for vaccine development, the speed at which more than 20 candidates made it to advanced development stages has been faced with skepticism and concern. How can a process that normally takes 10¬-15 years be compressed into 1 year without affecting the quality standards guaranteed under normal circumstances?

To solve this conundrum, the first step is to have a clear overview of the development stages of a vaccine ensuring its quality, safety and effectiveness, as shown below.

1) The exploratory stage consists of basic research screening the pathogen for potential target antigens, determining the most suitable vaccine type and formulation, and investigating the manufacturing process in detail.

2) Once promising vaccine candidates are identified, they are narrowed down in pre-clinical studies which are conducted in vitro (tissue/cell-culture systems) and/or in vivo (animal models) to evaluate their safety (including the best administration route and dosing) and immunogenicity.

3) At this point, regulatory authorities (RA) need to make sure that the vaccine’s quality profile is satisfying so that it can safely move on to clinical studies, which include 3 phases:

  • human pharmacology studies (phase I): based on 20-100 healthy volunteers, establishing the vaccine’s safety and immunogenicity as expected from laboratory results;
  • therapeutic exploratory studies (phase II): based on >100 volunteers (including subjects more at risk of developing the disease or not), confirming the vaccine’s safety and immunogenicity, and identifying the optimal vaccine dose, route of administration, schedule of immunization and common side effects; and
  • clinical efficacy and safety studies (phase III): based on >1000 volunteers presenting the disease or not, confirming the vaccine’s immunogenicity and evaluating its capacity to protect against the infection/disease development compared to a placebo/alternative treatment. Less common side effects are also identified at this stage.

4-5) After a successful phase III trial, a meticulous evaluation of the vaccine’s test results and manufacturing conditions (presented in a “marketing authorization” application) is performed by RAs to confirm the safety and quality of vaccine batches intended for market release. Ultimately, a vaccine will only be approved for manufacturing if its benefits are considered to outweigh its risks.

6) Finally, following approval, safety monitoring/pharmacovigilance (= phase IV trials) is continuously performed to ensure that any possible risk is detected and managed as fast as possible. In addition, every new batch of vaccine is tested for quality and safety before its commercial release.

In a public health emergency such as the Covid-19 pandemic, none of these development stages can be neglected. However, efforts can be made at all levels to make the process faster and more efficient.

First, in the context of Covid-19 vaccine development, several newly developed technologies have proved critical to accelerate the pre-clinical development stages:

  • High-speed genomic sequencing was used to identify the pathogen within record time using samples collected in December 2019. The complete genome sequence of SARS-CoV-2 was released online on 10th January 2020, allowing scientists to share information rapidly and to start searching for vaccine targets as early as January 11th.
  • While multiple types of Covid-19 vaccines are currently under investigation/development, the newest generation of vaccines based on DNA and RNA platforms are likely to be safer (no use of live viruses) and to speed up the development process as they are easily produced without need for culturing.

Second, vaccine developers have managed to reduce clinical development time by conducting several clinical studies simultaneously, by overlapping clinical trial phases, and by increasing the human resources appointed to discuss development strategies and to analyze study results.

Moreover, the European Medicines Agency (EMA) has helped to accelerate the evaluation stage (while still following the mandatory standard procedure) by:

  • creating the COVID-19 EMA pandemic Task Force and the EMA COVID-19 Steering Group, which are fully dedicated to addressing the challenges raised by the Covid-19 pandemic;
  • providing early scientific support to vaccine developers so that the most reliable methods and study designs are used to generate robust data, and that acceptance criteria for quality, safety and efficacy are considered in early development stages; and
  • adopting a rolling review cycle (i.e. data is evaluated continuously as it becomes available instead of waiting for the usual marketing authorization application) and reducing the official evaluation timeline from a maximum of 210 to 150 working days.

Of note, this accelerated evaluation process may result in a “conditional marketing authorization”, valid for one year, and subjecting the vaccine developer to specific obligations (e.g. completing additional studies for more comprehensive data) within defined timelines.

Finally, at the manufacturing level, considerable increases in human and financial resources help to ensure rapid large-scale production of approved Covid-19 vaccines. The EMA is also following up on Covid-19 vaccine-related safety risks through the development of a Covid-19 pharmacovigilance plan.

In conclusion, the dramatic acceleration observed in the development of Covid-19 vaccines appears to largely rely on a massive increase in human and financial resources, together with more flexible/continuous dialogue within the scientific community, as well as between vaccine developers and RAs. In addition, the emergence of promising new technologies may prompt faster and more efficient vaccine development in the future, even outside the context of a pandemic.

Morgane Florens,
CLS Writer Life Sciences


  • EMA website: European Medicines Agency | (
  • European vaccination portal: Vaccine facts (
  • “Vaccine Against Covid-19 Disease – Present Status of Development”, Ashok Kumar Dutta 2020, The Indian Journal of Pediatrics, DOI: 10.1007/s12098-020-03475-w.
  • “The COVID-19 Vaccine Race: Challenges and Opportunities in Vaccine Formulation”, Wang et al, AAPS PharmSciTech (2020) 21:225; DOI: 10.1208/s12249-020-01744-7.
  • “Vaccine development and therapeutic design for 2019‐nCoV/SARS‐CoV‐2: Challenges and chances”, Ghaebi et al., The Journal of Cellular Physiology, DOI: 10.1002/jcp.29771.

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