An incurable disease during the 20th Century (mainly before 1950), which paralyzed millions in the world, the people cursed with this disease did not how to use their arms and legs again. This disease was rampant and there was neither hope nor cure. Then, John Edward Salks, after a lot of experiments, trials, and errors, invented the Salk vaccine in the year of 1955. Today, if Poliomyelitis has become a history that will never repeat itself, it is all due to his genius invention.
ABOUT JONAS SALK
Jonas Edward Salk was born to Russian-Jewish immigrants, Daniel and Dora Salk, on October 28, 1914. He was the first and only member of his family to attend college. He became a scientist physician at Mount Sinai Hospital after graduating in Medicine from the New York School of Medicine in 1939.
He went to the University of Michigan in 1942 to work on a research fellowship where his primary work was to develop the influenza vaccine. He started working there as an assistant professor of Epidemiology at the University. During this course, he got an opportunity to reconnect with his mentor, Mr. Thomas Francis, who was the head of the Epidemiology department. It was from him he learned about the methodology of developing a vaccine.
At the Virus Research Laboratory, Salk got appointed as the Director of the Virus Research Laboratory. He began to develop various techniques that would help him develop the vaccine to eradicate paralytic poliomyelitis, which had frightened the entire mass, after receiving funding from the March of Dimes.
He had a strong conviction that his vaccine could immunize any patient from polio without risking his or her life, which was a stark contradiction to the prevailing scientific opinion. He started administering his vaccine to volunteers who were not affected by Polio. These volunteers included himself, his wife, and their children. Fortunately, all of them developed anti-polio antibodies and experienced no dangerous side effects from the vaccine.
National testing began in 1954 on around one million children ranging from six to nine years of age. This vaccine miraculously dropped down the average number of polio cases from 45000 to 910 after the vaccine was declared safe and effective on 12th April 1955.
The best part about this was that he never patented his discovery just to make sure that his vaccine can be distributed as widely as possible at a lower cost. This means he made this vaccine with an altruistic motive, to free mankind from the curse of Polio, and never really made any monetary gains out of it. After finding the Salk Institute of Biological Studies in La Jolla, he spent the latter researching about the cure for AIDS.
ABOUT THE VACCINE
The inactivated polio vaccines are considered to be the safest. Both oral and inactivated vaccinations are safe and can be given to HIV-infected patients as well as pregnant women. As the form of the vaccine virus has reverted to the causing disease, poliomyelitis, a new oral polio vaccine was developed. This makes the vaccine safer and at the same time, prevents future vaccine outbreaks.
To achieve global polio eradication, the interruption of person-to-person transmission is very important since the polio virus does not have a non-primate reservoir existing naturally, and the survival of this virus for a prolonged period in the environment appears to be remote.
DETAILS OF THE VACCINE
Polio vaccines are primarily of two types- oral polio vaccine and inactivated polio vaccine.
- Inactivated Polio Vaccine
90% or more individuals developed protective antibodies when the Inactivated Polio Vaccine was introduced into their bodies. Although the duration of immunity induced by this vaccine is not known for certain, a complete series can vouch for immunity for quite several years. As this vaccine had a small risk, it replaced the oral vaccine in many developed countries.
- Oral Polio Vaccine
It was easier to administer oral polio vaccines in comparison to inactivated polio vaccines. As there was no need for sterile syringes, administration of polio vaccines during the mass vaccination campaigns was possible. The best part about the oral polio vaccine was that the immunity provided by this vaccine was long-lasting as both humoral and cell-mediated immunity were provided.
When three doses of this vaccine are administered, protective antibodies are developed among more than 95% of the recipients. As the polio virus enters through the intestine, the oral polio vaccine provides excellent immunity in this site. This live virus has some stringent requirements concerning transportation and storage, especially in remote and hot areas. The immunity this vaccine offers is lifelong.
Side Effects
Although the vaccine has been a boon and has played an important role in eradicating a terrible curse, it did come with certain side effects. However, the side effects are nothing in comparison to the eradication the vaccine has brought in.
Firstly, the inactivated poliovirus can cause allergic reactions mainly due to the presence of neomycin, polymicyn B, antibiotics, and streptomycin. Allergic reactions like breathing difficulties, skin rash, and weakness can arrive within a few minutes or even after a few hours of taking the vaccine.
Secondly, there are also possibilities of vaccine-induced polio. As the vaccine derived from the attenuated virus and is usually excreted from vaccinated people only for a short period, the areas with poor sanitation automatically facilitate the spontaneous reversal of the vaccine-derived virus to an even more virulent form which can infect unvaccinated people once it spreads into the environment. To mitigate this side effect, the World Health Organization (WHO) has switched from a bivalent to a trivalent polio vaccine.
CONCLUSION
Even since the discovery of the Salk Vaccine, three doses of the oral polio vaccine and at least one dose of the Inactivated Polio Vaccine are given to newborns starting from six weeks of age with a gap of at least four weeks between the doses. Polio, which once used to cripple so many in the world today is completely eradicated, all thanks to the contribution of the great scientist, Jonas Salk.
By: Somdatta Ghosh
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