In April a six-year-old boy in Papua New Guinea was diagnosed with the polio virus. Recently two more children in the same county were also found the harbor the virus, making it an official outbreak of poliovirus, according to the World Health Organization (WHO). While this is just three cases, this is an unfortunate and serious development.

We are in the midst of an epic story about polio and its possible eradication. I hope we are at the end of this story, but we won’t know until it happens. Poliomyelitis (polio) is caused by a virus (poliovirus), an enterovirus and member of the family of Picornaviridae. It is spread from human-to-human contact, mainly through the oral-fecal route, but can also be spread through common contact with water or food.

The virus enters and multiplies through the intestine, which is why it is classified as an enterovirus, but can spread to the nervous system. There it can infect the anterior horn cells of the spinal cord – the neurons that control muscles – and therefore can cause paralysis.

There is no cure for polio once infected. The only treatment is prevention, which is accomplished through sanitation and vaccination. There is the potential to eradicate polio from the world, because it has no non-human reservoir. This means the virus only infects humans. Many other viruses, like Ebola, can infect animals. That means that even if there is no human on the planet with the virus (called “elimination”), it can survive in the wild in animals, and then from there cause an outbreak in humans.

So far only two diseases have been completely eradicated – smallpox and rinderpest. Other infectious diseases that have the potential to be eradicated include: poliomyelitis, yaws, dracunculiasis, malaria, measles, mumps, rubella, lymphatic filariasis and cysticercosis.

Of these we are only close to eradicating polio.

In 1988 about 350,000 people per year were paralyzed due to poliomyelitis. That was the year the Polio Global Eradication Initiative began. This is a public-private partnership involving the WHO, the UN, the CDC, Rotary International, and the Bill & Melinda Gates Foundation. The initiative mainly involved improving sanitation and medical care in endemic areas, and distributing polio vaccine, which is cheap, safe, and effective.

As a result of his eradication effort there were only 15 cases of polio in 2017 – the effort reduced cases of polio from 350,000 to 15. This, of course, stands as a major piece of evidence that vaccines are effective, despite the absurd denials of the anti-vaccine community.

Polio is now endemic in only three countries, Pakistan, Afghanistan, and Nigeria. Stamping out these last reservoirs of virus, however, has proven more difficult than anticipated. We have essentially been stuck here for the last 15 years – we are right at the finish line, but cannot take the last three steps to cross it.

This is why any cases of polio outside of these three countries are devastating. Hopefully, the cases represent a self-contained outbreak. The county in which the cases were found is fairly isolated, which is good. Also, to clarify, and outbreak does not mean that the virus is now endemic (self-sustaining) in Papua New Guinea – but efforts need to be made to contain the outbreak so that it does not become endemic.

I cannot help (being the nerd that I am) to liken the situation to Isildur and Elrond at Mount Doom. Isildur held the one ring in his hand, standing over the flow of lava, and all he had to do was let it drop and the evil of Sauron would have been eradicated. But “Evil was allowed to endure” and almost took over the world. It is an iconic tale, because we can relate emotionally to being so close to ultimate victory, only to lose everything.

In the case of polio, the reason we have been unable to let the ring fall into the lava is because of anti-vaccine sentiment. Yes – there are challenges in the three remaining endemic countries in terms of medical infrastructure and sanitation, but so were there in many other countries where the virus was eliminated. The critical difference was fearmongering about vaccines.

Some Muslim religious leaders in Nigeria have been preaching that the polio vaccine is a Western conspiracy, and will spread AIDS and infertility. This kind of fear is deadly, because eradication depends upon vaccinating every child. There has been progress against these conspiracy theories in Nigeria, but not enough to achieve elimination.

In Pakistan and Afghanistan conspiracy-fueled fear of the vaccine is also a problem (mostly spread by the Taliban). The Taliban also spread rumors that the vaccine contains ingredients like pork, which are forbidden in their religion, or that the people giving the vaccine are actually spies.

Unfortunately this latter rumor was increased when the CIA actually used a fake vaccine program to help track down Osama bin Laden. While successful, that move was highly criticized for adversely affecting the polio eradication effort.

So here we stand, at the precipice of Mount Doom, holding the ring of polio over the lava. It seems that every year the WHO proclaims that we can eradicate polio by the end of the year. I don’t doubt that this is true, but yet another year goes by and that last little bit of polio endures. Meanwhile, we occasionally see outbreaks in other countries like Papua New Guinea, exported from the remaining endemic countries.

Recently there was a report of a case of polio in Venezuela. Fortunately that turned out to be a false alarm, but the risk is real.

The polio eradication effort also shows how, now more than ever, we are truly living in a global world. We are all in the same boat – we can only eradicate diseases like polio if it is eradicated everywhere. We have a vested interest in the political and social stability of countries like Nigeria and Pakistan. Poverty in developing countries affects everyone.

I applaud the polio eradication effort, and they deserve tremendous support to help get them over the finish line. This support includes opposing the anti-vaccine movement, their conspiracy theories, and their pseudoscience. The failure to eradicate polio so far is partly on them. The movement largely consists of privileged Westerners who have the luxury of denying vaccines because they live in countries with great sanitation, where many vaccine-preventable diseases have already been eliminated.

But their pseudoscience and conspiracy theories affect all of us.


Posted by Steven Novella

Founder and currently Executive Editor of Science-Based Medicine Steven Novella, MD is an academic clinical neurologist at the Yale University School of Medicine. He is also the host and producer of the popular weekly science podcast, The Skeptics’ Guide to the Universe, and the author of the NeuroLogicaBlog, a daily blog that covers news and issues in neuroscience, but also general science, scientific skepticism, philosophy of science, critical thinking, and the intersection of science with the media and society. Dr. Novella also has produced two courses with The Great Courses, and published a book on critical thinking - also called The Skeptics Guide to the Universe.