What do polio and smallpox have in common? These are both dreaded viral diseases that science has (smallpox) or soon will (polio) completely eliminate from the planet through vaccination. Unlike many viruses that lurk in animal reservoirs, only humans are the natural hosts for both of these viruses. Smallpox virus and poliovirus persist by spreading from person to person and by being picked up from contaminated surfaces or water and food. Fortunately, neither virus survives beyond a few weeks to months outside the human host. Because of these properties, once vaccination has eliminated human cases everywhere in the world then the only viruses left are those in the environment. After several months with no human infections, any remaining viruses are nonviable and the disease is eradicated.
Using a massive global vaccination campaign to stop human cases, the smallpox virus was vanquished in 1980 and there has never been another human who suffered from this feared pathogen. Given the success at eliminating smallpox, in 1988, the World Health Organization (WHO), established a global initiative to eradicate polio by the end of the 20th century. With effective vaccines available, a campaign to innoculate the world took the prevention effort to every nation on the planet. The program was successful in eliminating polio in many countries and continents, with global cases falling from over 50,000 per year to less than 1000 by the year 2000. Still, the ultimate goal of eradication failed as polio stubbornly remained in a few countries where factors such as poverty, geographic isolation, and political and military strife thwarted efforts to vaccinate all the vulnerable populations. Over the last 20 years, the vaccination efforts continued and polio cases decreased steadily to an all-time low of only 22 cases worldwide in 2017. In August of last year, the African continent was declared poliovirus free, so now Afghanistan and Pakistan are the only two nations where poliovirus remains. Unfortunately, as long as poliovirus remains anywhere on Earth, then polio vaccination remains a must for children everywhere as the virus could be unknowingly carried from the remaining endemic areas to any country in the world.
With the end of polio tantalizingly close, the Global Polio Eradication Initiative (GPEI) announced a new $5.1 billion push to exterminate polio completely by the year 2026. With effective funding, a new vaccine, and renewed political will, GPEI is optimistic that the final battle with poliovirus can be won in this decade. As with smallpox, the elimination of poliovirus from the entire world will be another dramatic public health success. Hopefully soon, polio will become an extinct virus and nothing more than a historical note in modern medicine’s battle with infectious diseases.