POLIO ERADICATION--TWO STRAINS GONE, ONE TO GO

The three-decade-long campaign to eradicate polio--not long ago a worldwide scourge--passed an important milestone this month. The Global Polio Eradication Initiative (GPEI) announced the eradication of wild poliovirus type 3 (WPV3). Type 2 was declared eradicated in 2015. That leaves only one type of wild polivirus, WPV1, still in circulation.

 Somali child receiving an injection of inactivated poliovirus

Credit: PV2 Andrew W. McGalliard

Public Domain

That good news is augmented by the fact that WPV1 only exists in two countries, Afghanistan and Pakistan. This allows resources to be focused on those last two remaining reservoirs of the deadly virus.

However, the goal of finally eradicating polio remains elusive. There have been more cases of wild-virus-caused polio in those two countries (18 and 76 respectively) this year than in 2018. And, there have been a significant number of cases caused when the weakened virus used for oral inoculation mutates back to a disease-causing form. Although very rare, when millions of children are given the oral vaccine, mutation back to a virulent form is enough to keep the disease alive.

To address this problem, GPEI has now shifted into its Polio Endgame Strategy. This is a multifaceted campaign involving continued mass inoculations, rapid response teams to quickly contain and snuff out any flareups, and a shift from oral live attenuated immunization to inoculation by injection of completely inactivated virus. The endgame campaign is estimated to cost $4.2 billion and take four years. If it succeeds, humanity will have eliminated a second deadly disease (smallpox was the first) and no child will ever again be killed or paralyzed by polio.

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You can read an executive summary of the endgame strategy here.

ZERO POLIO CASES SO FAR THIS YEAR!

Followers of Zerospinzone know that I've been following the worldwide effort to eradicate polio, a disease that killed or paralyzed 350,000 children per year not long ago. Since the Global Polio Eradication Initiative (GPEI) was launched in 1988, polio has been wiped out in country after country and continent after continent. The wild polio virus now hangs on in only a few countries such as Pakistan, Afghanistan and Nigeria.

The good news is that in the first month of 2019 exactly zero cases of polio were reported. Not a single child fell ill with this once terrifying and deadly scourge. What a great achievement!

Polio virus--it may soon exist only in a few super-secure laboratories

This doesn't yet mean that the virus has been completely eradicated. It may still lurk undetected in a few countries, and there's a very small but real risk that the attenuated virus used for oral inoculations can mutate in some individuals and cause cases of the disease. This complicates the polio end-game, during which at-risk populations may need to receive injections of a vaccine that uses killed virus particles, a costlier and more difficult undertaking.

However, this month with no polio cases tells us that the decades-long worldwide campaign to eradicate polio is closing in on its goal.

The apparently growing number of parents who are choosing not to have their children vaccinated might give a moment's thought to the 1950s, when polio paralyzed 15,000 children per year in the U.S. alone, and smallpox disfigured or killed an estimated 50 million people every year. A massive, worldwide effort similar to the current battle to eradicate polio succeeded brilliantly; the last case of smallpox occurred in 1979. Had anti-vaccination sentiment and propaganda been as strong then as now, millions of people would have been disfigured, paralyzed, or would have died needlessly.

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Seventy people, most of them children, have died from measles in the Philippines just in the past month. Every one of those deaths was preventable.

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Tightening the noose around the polio virus

The world moved a step closer to eradicating polio, a sometimes fatal crippling disease that killed or paralyzed half a million people per year in the middle of the 20th Century. 

Today, the Global Polio Eradication Initiative, GPEI, announced that July marked two full years with no cases of polio caused by the wild polio virus. This is a major milestone in the ongoing campaign to clear Africa, and soon the whole world, of the polio virus.

Compared to hundreds of thousands of cases not long ago, so far this year there have been only 19 polio cases worldwide, limited to two war-torn countries, Afghanistan and Pakistan.

Within a few years, we may completely eradicate polio, and free the world's children and their parents from this devastating disease forever. The only other human disease that we have been able to eradicate is smallpox, after an enormous international effort completed in 1979.

Children in Iron Lung ventilators

Rancho Los Amigos Hospital

Downey, California, 1953

This near-eradication of polio has been possible due to the existence of two effective polio vaccines, starting with the inactivated polio virus vaccine developed by Jonas Salk in 1952, administered by injections, and followed by a weakened virus vaccine that could be delivered by mouth, developed by Albert Sabin and widely used starting in 1961.

Most of the global eradication program has relied on the weakened-virus oral vaccine, which is less expensive and easier to administer than the killed-virus injectable vaccine. However, in rare cases the inactivated virus can mutate back to a disease-causing form. As a result, the last stages in eradicating polio will require a switch back to injections.

Funding for the multi-billion dollar eradication program comes from a variety of national, international and private sources. Rotary International deserves special praise for spearheading this effort starting in 1985.

Experts at the Global Polio Eradication Initiative hope to overcome the final obstacles and wipe polio our completely within the next few years.