How Are Vaccines Developed?
- ES
- Nov 1, 2020
- 3 min read
Through the COVID-19 pandemic, everyone in the world is waiting for the vaccines and the medicines to be developed. The major pharmaceutical companies are racing to develop vaccines. People say vaccines are the key to returning to our mask-free lives before the pandemic. (You can read about why people get vaccinated and how a vaccination works at our previous post: Nanotechnology: Can these skin patches vaccinate the world instead of needles?) So, how are vaccines developed and why does it take so long?
History of a vaccines
In the 15th century China, people collected and crashed smallpox scabs and blew them up the nostril. That may sound dirty and strange but people did it because they found out people who had contracted smallpox did not get infected with smallpox again.
In the 18th century, British physician Edward Jenner had noticed milkmaids who had contacted with cowpox, did not get smallpox. Cowpox had much milder symptoms than smallpox. In 1796, he scratched a cowpox pustule to an 8-year-old boy. The boy easily overcame the virus and became immune to it. Two years later, Jenner published his results in a book.
Louis Pasteur developed vaccines against anthrax and rabies in 1881 and 1885. He weakened the pathogens (organisms that cause diseases) by oxygen and heat. Gamille Guérin developed a tuberculosis vaccine in the early 20th century. He developed a vaccine by weakening a bovine strain of the bacterium. However, there was problem with attenuated virus that the weakened viruses can mutate and on some rare cases, vaccines can cause the disease. Because of that, vaccines that were developed in 19th and 20th century allowed the pathogens to be killed entirely by heat or formalin.
In recent days, researchers developed vaccines by relying on RNA or DNA extraction from pathogens and injecting them into our bodies. Furthermore, the trial COVID-19 vaccines were developed using mRNA that was extracted from SARS-Cov-2.
Development of vaccines
There are generally three phases of vaccine development: exploratory research, clinical testing, manufacturing.
Exploratory research: experiment, replicable vaccine designs. The goal of this stage is to find ways to immune our body in a safe way
Clinical testing: evaluated for safety, efficacy, and side effects. There are three-phases in the clinical testing. In Phase 1, small numbers of people get vaccinized. In Phase 2, people who have characteristics receive the trial vaccine. Also, researchers try to determine the right dosage and delivery schedule. In Phase 3, the vaccine is tested with more people and identify rare side effects.
Manufacturing: vaccines are produced and distributed
Why does it take so long to develop vaccines?
It takes 15 to 20 years in average but researchers are trying to shorten it by using numerous strategies. For example, the first testable Zika vaccine was developed in 7 months by working on different models simultaneously, but, for the trial COVID-19 vaccines, it took 42 days. If pathogens are similar with other pathogens that already have vaccines, researchers can use approved treatments.
Manufacturing vaccines is a complex biological process because every vaccine has its own unique blend of biological and chemical components.
Why some people don't get vaccinated
People refuse to get vaccinated because of many reasons like:
Autism
high risk of potential allergic reactions
believes that pharmaceutical companies are making money of it
believes that vaccines do not protect you
religious belief
However, many researchers tell us that vaccines are not the cause of autism. Many people forget that vaccination is more beneficial and think that there is more harm than benefit. History of vaccination disproves that as infectious diseases in the past were eradicated by getting vaccines.
References
Comments