May 29, 2024

Developing a safe and effective vaccine is extremely demanding and methodical work. And once scientists make it, we will need many doses too. The World Health Organization, in February 2020, said it will take tentatively 18 months for a vaccine to be developed for safe use.

The fastest vaccine ever developed was for mumps and that took 4 years. The average time taken to develop an effective vaccine is 10-15 years, so if the COVID-19 vaccine, either an emergency use only one or a fully approved one, is developed within a year or 2 it will be a record. Even with global efforts, it takes a long time to develop a vaccine for any disease. Predicting when the COVID-19 vaccine will be available is nearly impossible. Let’s explore why. 

To produce any kind of vaccine there are 6 stages, each with a highly variable timeline. I will go through each stage and explain it in detail.

The first stage is known as the research and development phase which is also known as the exploratory and the discovery phase. In this phase, scientists and companies spend millions of dollars into studying the pathogen and coming up with different approaches to produce the vaccine. Although typically this phase takes 2-4 years, with modern technologies and knowledge already speeding up the research and development process and the corona virus being similar to the previous SARS virus, researchers might have gotten a head start. To combat the novel corona virus, researchers have already started developing a nucleotide-based vaccine, which triggers our immune system using the virus’s genetic code instead of its proteins.

The second stage is known as the preclinical research stage. In this stage, the experimental vaccine is tested in cell cultures and animals to see the immune response. If there is no immune response or the vaccine is harming the cells then it’s back to square one. Scientists have to again start with phase one, i.e. research and development. If the vaccine produces the desired immune response without harming the cells then scientist move towards phase three of vaccine development which is the clinical research stage. The preclinical stage takes about 1 year.

In the next clinical research phase, the experimental vaccine is tested on humans. The vaccine is first tested on a small group of people and then a bigger group and then an even bigger group usually in the outbreak area. Due to the COVID-19 pandemic being so serious, scientists have proposed the so-called challenge trials, something which has never been done before. In this trial, they vaccinated people are intentionally exposed to the virus in a controlled environment and the results are recorded. This trial is supposed to accelerate the timeline of phase three as these clinical trials can take years to complete.

If the results are as desired, researchers nad companies move towards phase four which is the regulatory review. In this phase, the manufacture applies for a licence to produce the vaccine. In the US the authorization of this license is done by the Food and Drug Administration (FDA) and in India by India Central Drugs Standard Control Organization (CDSCO). This procedure usually takes 10 months but I am sure during this pandemic they will speed up this process.

After acquiring the license, manufacturers will have to scale up the production, that is by building factories which will take years and hundreds of millions of dollars. Of course, due to the current situation the production will be fast but still manufactures will need to produce enough raw materials, ensure the quality of the drug and supply it to the whole world. It’s a very time-consuming task and time is of the essence here.

But we still aren’t done. After the manufacturing and distribution are done, the next phase is post-market safety monitoring. In this phase organizations like the FDA will monitor the drugs and take note of the results, problems and complaints.

Methodically working through all these stages to ensure production of a safe and effective vaccine can and will take up years. Currently, global efforts and scientists working on two or more phases simultaneously may help to fast track the whole production. So when the government says that they hope to develop a vaccine by the end of 2020, they are referring to emergent use only vaccines. This means that during times of emergency, the FDA or similar organizations may allow unapproved drugs or unapproved uses to treat a disease.

Making vaccines is a very tedious, dangerous and important task, so we should give it time and till then follow the COVID-19 safety guidlines and take care.

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