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.

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.

 

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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