The world is closer than ever to eradicating polio forever

 As Zerospinzone readers know, the eradication of polio has been the target of a massive international effort started in 1988 and led by the World Health Organization, the United Nations Children's Fund and the Rotary Foundation. The effort has been incredibly successful and in fact has pushed the deadly polio virus to the brink of extinction. So far this year there have only been 4 cases of poliomyelitis caused by the wild polio virus. As far as we know, the wild virus hangs by a thread in just two countries, Pakistan and Afghanistan.

Administering the oral polio vaccine

Credit: Michael Tsegaye, Flickr

However, the final eradication of the disease has been complicated by the fact that the weakened polio viruses used in the Oral Polio Vaccine occasionally mutate to a virulent, disease causing form. This kind of mutation is very rare, but with hundreds of millions of doses administered, in recent years there have been more cases of poliomyelitis caused by the mutated vaccine, especially the type 2 vaccine, than caused by the wild virus itself. (The polio virus comes in 3 varieties, each of which has its own vaccine. The type 1 and type 3 viruses appear to have been eradicated, and recent vaccine-derived cases have all come from the type 2 vaccine.

The good news is that researchers have developed a new type 2 oral vaccine--nOPV2--that is genetically much more stable than the earlier version, and so much less likely to mutate to a disease-causing form. The new vaccine successfully snuffed out a recent outbreak of vaccine-derived illness in Tajikistan without leading to any new cases. This successful use of the novel type 2 vaccine provides hope that the few countries where either wild polio virus or disease-causing forms of the older type 2 vaccine still exist can soon join the rest of the world and be certified as completely free of polio.

Then--hopefully very soon--polio will join smallpox as once dread and deadly human diseases that have been permanently wiped from the face of the earth. 

SO CLOSE TO THE ERADICATION OF POLIO...

 We're nearly half way through 2021. So far this year, there have been just two cases of polio caused by the wild polio virus, one in Afghanistan and one in Pakistan. The decades-long international effort to eradicate this crippling and deadly disease is tantalizingly close to success. The wild polio virus, once endemic globally, now hangs on in just those two conflict-ridden countries.

The oral polio vaccine--

inexpensive, effective

but can revert to a virulent form

Credit: Michael Tsegaye/Flickr

Unfortunately, there have been substantially more--nearly 100--polio cases caused when the oral polio vaccine mutates back to a virulent form.

The polio end game will require the gradualy replacement of the oral polio vaccine with the inactivated polio vaccine, which is incapable of causing poliomyelitis. 

Polio will officially be declared eradicated when three years have passed without any documented polio cases caused by the wild polio virus. That will mark just the second human disease that we have been able to eradicate, the first being smallpox, declared eradicated in 1980.

POLIO ERADICATION UPDATE 4-30-21

 As Zerospinzone followers know, I'm fascinated by the quest not just to control or cure deadly diseases, but to eradicate them completely. The scourge of smallpox was defeated in 1980, and we've been closing in on polio since the deployment of the first (Salk, inactivated virus) vaccine in 1954, country by country, continent by continent.

Polio has been with us for thousands of years

This depiction is from Egypt's 18th Dynasty--1403 to 1365 BC

Credit: Deutsches Grünes Kreuz

Today, the wild polio virus hangs on in just two countries, Pakistan and Afghanistan, with just one case reported in each of those countries so far this year. We may really be on the verge of totally eliminating the wild polio virus from Planet Earth.

Even when that remarkable feat has been accomplished, the battle won't be over. The oral polio vaccines that have been so incredibly successful have one flaw--the attenuated viruses they use very occasionally mutate back into disease-causing variants. So far this year there have been 73 cases in 10 countries, fewer than last year at this time, but still a serious problem. 

The Global Polio Eradication Initiative has developed and initiated a strategy or endgame to deal with this issue. They plan to gradually phase out the massive provision of attenuated oral vaccines, phase in the use of an inactivated-virus vaccine as needed, and, hopefully, bring the millennial reign of polio to an end.

I'll continue to report on their progress towards this grand goal.

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REA 4-30-21 

DON'T TELL THE ANTI-VAXERS--AFRICA HAS NOW BEEN DECLARED WILD POLIO FREE

In a celebration-worthy achievement, the wild polio virus has now been eradicated across the entire African continent. The August, 2020 victory declaration follows four years without a single case of the deadly paralytic disease caused by the wild polio virus anywhere in Africa.

This represents an enormous success for the decades long worldwide program, led by the World Health Organization, the United Nations Children's Fund and the Rotary Foundation, to eradicate polio worldwide.

Child receiving oral polio vaccine--Credit: UNICEF 

There are three types of wild polio virus. Of these, two have been eliminated worldwide, and now exist only in laboratories. The remaining virus, Type 1, survives in just two countries, Pakistan and Afghanistan, where it has sickened 105 people, mostly children, so far this year.

When the global polio eradication initiative kicked off in 1988, an estimated 350,000 people were paralyzed or killed by poliomyelitis every year. In the United States alone, in 1952, there were more than 57,000 cases, more than 21,000 leading to paralysis, and more than 3,000 deaths. 

While the current near-eradication of polio represents one of humanity's greatest successes in disease control, much more work remains. The oral polio vaccine that has been the core of the eradication program relies on live, but weakened rather than inactivated poliovirus. Very rarely, the weakened virus can accumulate mutations that allow it to cause disease outbreaks again. In recent years there have been as many or more vaccine-derived polio cases than those caused by the wild virus. 

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REA

The end game--finally eradicating the wild virus everywhere while concurrently stopping the transmission of vaccine-derived cases is complicated but within reach.

In the meantime, for the first time in human history, people on six of Earth's continents--more than 90 percent of the world's population--are free from this deadly disease.

 

POLIO STRIKES BACK--ERADICATION ENDGAME SURPRISINGLY DIFFICULT

This has been a very mixed year for the global polio eradication campaign.

What the global polio eradication campaign

wants never to happen again

The good news is that two of the three strains of wild poliovirus have been conquered; they no longer exist except in laboratories.

The mixed news is that the remaining wild poliovirus only exists in two countries, Afghanistan and Pakistan. However, the number of cases in both countries, especially in Pakistan, has been higher than in 2018. The two countries suffered 125 cases of polio compared to just 33 last year, 101 of those in Pakistan. In both countries, strife, insecurity and anti-vacccination propaganda and rumors have enabled the virus to hold on.

The bad news is that the number of people--mostly children--sickened by poliovirus that has mutated back to a virulent form from the live-but-attenuated polio vaccine has more than doubled since 2018. This back-mutation only occurs in one person out of an estimated 2.8 million, but since 450 million children are getting the attenuated vaccine every year, a significant number of cases are inevitable as long as the oral vaccine remains in wide use--unless the surrounding population has a very high rate of "herd immunity." There were 241 such cases in 2019 vs. just 104 in 2018.

The solution is complex, but at hand. In part, it depends on the rapid release of an oral vaccine against the type 2 poliovirus, which is expected to be less likely to mutate to a virulent form. You can read about the global polio endgame strategy here. Plans and resources are in place to make this transition, and the intense, decades-long global campaign to wipe out this deadly disease once and for all will succeed, even if not quite as quickly as hoped.

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REA

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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WE'RE SO CLOSE TO ERADICATING POLIO

As followers of zerospinzone.blogspot.com know from previous posts, I'm enthralled by the goal of not just treating or curing diseases, but eradicating them entirely.

Among human diseases, smallpox was the first to be wiped away, with the last case of a natural infection by this once devastating scourge occurring in October, 1977.

Polio, a paralyzing and sometimes fatal disease that struck down more than 500,000 people per year, most of them children, as recently as the 1940s and '50s, will hopefully be the next to go. Starting with the development of the Salk inactivated virus vaccine in the early 1950s and the Sabin attenuated virus oral vaccine in the early 1960s, polio has been eradicated in country after country, continent after continent, through massive, sustained, costly and often extremely difficult public-health efforts.

 An infant receives the oral polio vaccine at a mobile clinic in Afghanistan, February 15, 2017

Credit: World Health Organization (WHO)/ S.Ramo

This enormous international effort has been incredibly successful. So far this year, only three cases of polio have been diagnosed worldwide, all in war-torn Afghanistan. In other words, the wild polio virus that once circulated freely throughout the world, has now been caged and almost completely destroyed, and now may hang on in just one small corner of one country.

It will still take intense surveillance and continued mass vaccination programs to strike the final blow against this deadly disease and ensure that it can not flare up anywhere every again.

But the world is so very close. What an accomplishment it will be.

REA

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QUICK UPDATE ON POLIO ERADICATION PROGRESS -- WE'RE SO CLOSE

Followers of this blog know that I'm fascinated by the international effort to eradicate polio. Wiping out this paralyzing, often deadly disease will be one of humankind's great accomplishments. The only other human disease that we've been able to eradicate is smallpox--the last spontaneous case was in 1977.

According to the Global Polio Eradication Initiative, the effort is incredibly close to success, with just 5 cases reported worldwide this year, to May 24 (vs. 16 this time last year). In the early 1950s, before the Salk and Sabin vaccines were introduced, 15,000 children died or were paralyzed by the poliovirus every year just in the United States, 500,000 worldwide.

It's taken decades of dedicated, sometimes dangerous work by scientists, international organizations, and on-the-ground health providers to reduce that number from 500,000 to 5. The goal now is to shrink it to zero.

It appears that the polio virus now survives in just a few locations--the 5 cases all occurred in Pakistan and Afghanistan, destabilized by war and refugees. In addition, all 5 cases were caused by Wild Polio Virus 1 (WPV1), meaning that the other two strains of wild polio virus, WPV 2 and 3, may already be eradicated.

Wild Polio Virus Type 3

Credit: Manuel Almagro Rivas/CreativeCommons

Massive vaccination programs of at-risk children and adults are continuing, and will need to to continue for some time even after there are no more documented cases.

We're so close . . .

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Tightening the noose on the polio virus

Not long ago, the virus that causes the paralyzing, often deadly disease polio circulated freely worldwide, crippling or killing half a million people every year, including thousands in the U.S. and Canada.

The mid-20th Century development of the Salk and Sabin polio vaccines gave mankind the tools needed to eradicate this dreaded disease. It's taken 7 decades, but the worldwide campaign to wipe out polio, spearheaded by the UN's World Health Organization and UNICEF, Rotary International, the US Centers for Disease Control and The Gates Foundation, is closing in on the polio virus' last strongholds, Afghanistan and Pakistan.

5, 4, 3, 2, 1, 0! Let's end this terrible disease

Credit RIBI Image Library

So far this year, polio has only sickened five children, three in Afghanistan and two in Pakistan. At the same time, 116 million were vaccinated. With such an active monitoring and vaccinating program, the total eradication of polio is in sight.

That will represent just the second human disease to be complete eradicated. Another deadly viral scourge, smallpox, was completely eradicated nearly four decades ago through a similar worldwide campaign.

The eradication of polio will represent a second great achievement for mankind.

CLOSER THAN EVER TO ERADICATING POLIO

The global effort to wipe out polio, a disease that killed thousands and paralyzed tens of thousands of children in the US and the UK not that long ago, is tightening the noose around the deadly poliomyelitis virus.

Polio survivors/RIBI Image Library

The Global Eradication Inititative announced today that so far this year 27 children have been diagnosed from polio, down from 51 at this time last year. Just three countries are still finding new cases, Pakistan, Afghnistan and Nigeria. Despite war and instability, volunteers continue to bring vaccines to where they are needed, often despite great personal risk.

Type 3 polio virus

It will not be long before this ancient scourge, like smallpox, will be eliminated forever. The day can't come too soon.

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.