Why is Polio so dangerous?

There was polio everywhere in 1952. This virus killed or disabled almost half a million people per year for years, making surviving dependent on respirators, wheelchairs, and crutches. However, the United States had a 96% decrease in paralytic polio cases within a decade. Similar patterns quickly expanded around the world, and it appeared that we might be able to permanently eradicate polio. However, the virus began to retaliate in the twenty-first century. What causes these new rises, therefore, and how can scientists combat and eradicate this fatal illness?

We must first comprehend the actual threat posed by polio in order to respond to these inquiries. The majority of infected people only exhibit minor flu symptoms or none at all, with less than 1% of instances resulting in paralysis. Because of its high contagiousness, polio poses a serious threat.

Three polio virus strains have been identified historically, and they all usually get into our mouths through contact with contaminated feces or airborne droplets. This indicates that polio is quite common in areas with inadequate sanitation. Additionally, once infected, a person can spread the infection for three to six weeks, propagating a disease that is quiet and has few symptoms that can be tracked. This is what rendered polio incurable until the early 1950s, when US physician Jonas Salk discovered a cure.

He created an inactivated virus that, when administered intravenously, stopped the paralysis caused by all three strains. But this IPV, or inactivated polio virus vaccination, failed to prevent the polio virus from residing in our bodies and infecting others. Luckily, Albert Sabin, a Polish American scientist, was developing the oral polio vaccine, or OPV, concurrently. This much less expensive and simpler therapy included attenuated viruses, which are weakened versions of each polio virus strain that, once consumed, stopped polio from ever settling in the body.

IPV and OPV eradicated polio in one nation after another during the next decades. However, this arms race between viral evolution and medical innovation changed course around the turn of the century. Researchers found three different strains of polio, all of which were very identical to one another. Even more concerning was their provenance. One of OPV's biggest benefits until this time was that its attenuated viruses might travel through the air and immunize uninfected people, much like wild polio. However, scientists found that these weakened viruses may evolve into new vaccine-derived strains if they were present in undervaccinated populations for a few weeks. This does not imply that the attenuated vaccination was intrinsically harmful, to be clear.

Globally, OPV has previously been used to prevent wild poliovirus type 2—to eliminate all wild poliovirus from the West Pacific, the Americas, and innumerable other nations. Making sure populations reached a specific vaccination threshold was the problem—specifically, vaccination was required for at least 80% of each community to stop stresses from changing. We have thus adopted two strategies to combat polio in the present.

First, even safer versions of OPV have been created by vaccine makers. One or two varieties of attenuated poliovirus are present in monovalent and bivalent OPVs, respectively, lowering the potential mutational number of strains. Wild poliovirus types 2 and 3 were eliminated thanks to these vaccinations, and they are currently working to eradicate the final traces of the type 1 poliovirus in Afghanistan and Pakistan. OPVs that target vaccination-derived polio were also created by vaccine researchers.

Nowadays, vaccine-derived poliovirus is responsible for the majority of polio cases outbreaks of type 2 throughout the Middle East and Africa. In order to combat this strain, researchers developed a new vaccination with little chance of mutation.

Second, advanced technology is being used by front-line medical personnel to guarantee that each population reaches the 80% mark. They can discover and vaccinate isolated populations with the use of digital technologies like geospatial imaging and analysis. They make sure they don't miss any kids thanks to extensive surveillance systems. Additionally, waste surveillance systems used worldwide can notify us of any epidemics. The battle against polio is reaching a turning point right now.

The eradication of wild poliovirus is imminent, and with the development of new vaccinations, the eradication of strains generated from immunizations may not be far off. However, it is still difficult for doctors to get to places where there is social upheaval and armed combat. Furthermore, polio's hidden outbreaks might quickly increase if vaccination rates are not maintained at a high level. Therefore, we must continue to apply pressure to complete the task we began more than 70 years ago.