in a world overwhelmed by the present COVID-19 Epidemics, it is easy to forget about the existence of other viruses that can cause serious illness. One such virus that has affected our lives since the time of Egyptian civilization is the poliovirus. Every year October 24 is marked as World Polio Day to commemorate the birth of Jonas Salk, the American researcher who developed the first polio vaccine in 1955.
Poliovirus is the simplest known human virus. It is very small at only 30 nanometers. In comparison, SARS-CoV-2 is a slightly larger virus at about 100 nanometers.
Poliovirus was first isolated in 1909 by Karl Landsteiner and Erwin Popper and the first human coronavirus Leland was isolated by David Bushnell and Carl Alfred Brandley in 1933.
The poliovirus causes a disabling and life-threatening disease called poliomyelitis. The virus spreads from person to person and can infect a person’s spinal cord, causing paralysis. In about 25 percent of all people infected with polio, it causes very mild flu-like symptoms, including sore throat, fever, fatigue, nausea, headache and stomach upset, for about 2 to 5 days and they make a full recovery. Huh.
However, in a small proportion, infected individuals can develop ‘pins and needles’ or other symptoms such as tingling or pricking in their hands and feet, meningitis and paralysis of the arms and legs. Children under the age of five are most at risk of developing serious complications related to poliovirus, which affect their quality of life.
Poliovirus is highly contagious and can easily spread from person to person – the R-not value, that is, the number of people infected with polio in one infected person is 5-7. For Covid-19, the R-naught value is 1.4 to 3.9.
Polio virus is spread by person-to-person contact, particularly through the fecal-oral route. Poor hand hygiene, lack of access to clean water, improper sewage systems are the most common causes of incidence and transmission of polio. However, in the 1950s, the first polio vaccine was invented by Jonas Salk. It was a very safe and effective inactivated poliovirus vaccine, which was administered by injection.
While highly effective, at the time, the availability of disposable syringes was scarce, and the speed of vaccination was low. Another polio vaccine, invented by Albert Sabin in 1961, was called the oral polio vaccine (OPV). It was more easily administered to a larger number of people. A combination strategy was determined, and mass administration began. Polio eradication is one of the most ambitious global health initiatives in history, and will only be the second human disease in history to eradicate polio (the first was smallpox).
Today, the only places in the world where wild polio exists are Pakistan and Afghanistan. With the successful use of this vaccine, the number of polio cases decreased from 3.5 lakh in 1988 to 33 in 2018.
Because polio is highly contagious, no one is safe until everyone is vaccinated. Since the launch of the Global Polio Eradication Initiative (GEPI) in 1988, the rigorous efforts of the Ministry of Health and Family Welfare to monitor sewage samples for poliovirus and a strong immunization program in the form of a public-private partnership with Rotary International have led to It has made it. India has been declared polio free by 27 March 2014.
The science of vaccine development and our understanding of our immune system have greatly improved since the development of the polio vaccine. In the field of vaccinology, researchers have been working for decades on how to design and develop safe, effective, inexpensive vaccines.
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Various safe and effective vaccines against Covid-19 have been developed around the world using classic vaccine development techniques as well as more modern state-of-the-art technology.
Designing a strategy, developing a vaccine, testing its safety and efficacy is a laborious, time-consuming and costly process. However, in the times of Covid-19, vaccine developers had decades of data, abundant volunteers and enough funding to study the effectiveness of various vaccines. Collaboration between scientists, regulatory agencies, vaccine manufacturers has paved the way for us to make multiple vaccines against Covid-19 in such a short span of time.
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