Safely speeding up development of COVID-19 vaccines

A COVID-19 vaccine is likely the most efficient way to fight the coronavirus pandemic and return to normalcy. However, vaccines typically require years of development before wide distribution.
The fastest vaccine development prior to Pfizer’s COVID-19 vaccine was that for mumps, which took four years. The typical vaccine takes about a decade or longer (12 to 14 years). Researchers expedited development of a COVID-19 vaccine, so people can receive a vaccine as soon as possible.
In light of concerns about the potential health risks of an accelerated vaccine, we hope to explain how vaccine can safely be expedited. In order to understand the acceleration of the COVID-19 vaccine, we will first explain the typical vaccine development process.
Unlike conventional medications, which aim to treat a disease after symptoms have emerged, vaccines are intended to prevent disease. Typical vaccines aim to support the body’s immune system in fighting diseases by stimulating antibody production.
An antigen, a sub-part of a pathogen (something that can cause diseases), induces the formation of antibodies. After an antigen is introduced via a vaccine, the body’s immune system produces antibodies and learns how to fight the disease. Then, when the person is exposed to the actual antigens of a pathogen, their body has already learned the proper immune response and can better fight the disease.
The phases of vaccine development include: exploratory, pre-clinical, clinical development (three sub-phases), regulatory review and approval, and manufacturing and distribution. For a typical vaccine development process, the details and timeline for each phase are as follows.
• Exploratory phase (2-5 years): research-intensive phase to identify the antigen that will form the basis of the vaccine.
• Pre-clinical phase (around 2 years): Testing of the vaccine on non-human subjects (e.g. isolated cells and animal models) to determine if the vaccine safely produces immunity. The researchers then submit their vaccine for approval by the U.S. Food & Drug Administration (FDA) to start the clinical development.
• Clinical development phase (5-9 years): Following FDA approval, researchers enter the three consecutive sub-phases of the clinical development phase, in which the vaccine is tested on an increasing number of human subjects. During these three sub-phases, appropriate dosage, side-effects, immunization schedule, and effectiveness are determined. Safety and efficacy are confirmed in phase I before moving into phase II.
• Regulatory Review and Approval phase (1-2 years): The vaccine is once again approved by the FDA.
• Manufacturing and Distribution phases (highly variable): Finally, the vaccine can be manufactured. Perfectly tailored factories are created for each vaccine. Temperature-controls, millions of vials, and specific equipment and materials are among the many requirements for a vaccine factory. Once produced, the vaccine must be distributed, which involves many considerations. For example, one particularly important consideration for the case of COVID-19 vaccine distribution is temperature control, which requires expensive equipment (e.g. Pfizer’s RNA vaccine requires storage at -70 degrees Celsius in high-tech freezers).
Potential COVID-19 vaccines must still check all the boxes when it comes to the development process. So how can we expect to see a working vaccine that poses no health risks on such a shortened timeline?
First, the amount of research, funding, and overall hours invested in the development of a COVID-19 vaccine is unprecedented, with many companies working in parallel on different strategies to develop a vaccine. Furthermore, exploratory and clinical research phases, which began in early 2020, normally take years, but proceeded rapidly in just a few months each. By compiling information on other coronaviruses such as SARS-CoV, scientists were able to find similarities and guess at what the most effective vaccine antigen might be.
Additionally, companies like Moderna, Pfizer, and Inovio Pharmaceuticals have been perfecting cutting-edge vaccines composed of genetic material (RNA and DNA vaccines) that your cells can take up and use to produce antigenic proteins, more specifically the spike proteins found on the membrane of the virus While traditional vaccines are also being developed for COVID-19, these newer methods trigger your body’s immune response, but don’t actually require the virus itself. This eliminates the need to produce large cultures of viruses, which saves time and resources.
There are other ways to speed up the process without sacrificing safety. For the sake of time, measures have also been taken within the pre-clinical phase, the phase that involves testing on animals. Global regulations state that to begin human trials, data from animal testing must be presented and the candidate vaccine deemed safe, but there are no requirements for efficacy. Under non-pandemic circumstances, researchers would pay closer attention to the vaccine’s effectiveness in animals, however given the likelihood that human trials will result in different levels of success, it seemed acceptable to move forward and save time, and therefore more lives.
Similar shortcuts are seen in the clinical development sub-phases, where testing on larger volunteer populations may begin sooner once previous sub-phases indicate that the vaccine candidate is not harmful to humans. In the case that the vaccine candidate brings promising efficacy, the trials will have already moved forward safely.
It is worth knowing that the FDA approves COVID-19 vaccines for distribution only if they hold a 50% efficacy or better, meaning that out of 10 people who get vaccinated, five will not get sick. This may not seem like much, but there are huge benefits in terms of preventing the spread across large populations, for a vaccine that meets these standards.
Although we still have a long way to go in improving diversity of clinical trials, there is extensive care being taken to assure that all population types are included in the human testing phases despite the accelerated circumstances. A large and diverse testing panel is crucial in later phases of human trials, because it is possible that a vaccine proven to work for young and healthy people may not work well for elderly populations. The same goes for racial, ethnic, and gender-related diversities, so it is important to take everything into account as trials progress.
Additionally, vaccine researchers understand that every vaccine candidate has the potential to be the one that works. Because of this, companies have been scaling up manufacturing earlier on in the development process than they would outside of a pandemic. Many companies are preparing for mass production of a candidate vaccine as early on as the pre-clinical phase. In July and August large, government-funded deals were announced as part of “Operation Warp Speed,” which supported large-scale manufacturing costs and distribution preparations for numerous companies, including Pfizer and Moderna. In the case that a company’s vaccine proved effective in clinical trials, it would be ready to send out to the public.
This retroactive manufacturing is normally a huge financial risk, since companies must gamble vast amounts of time and resources towards something that may never work. But in this situation governments and other authorities are investing in these processes.
In the end, however, a failed vaccine is always helpful for determining future work, and is a step in the right direction even if it doesn’t provide us with the solution we need.
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