Tag: polio

Myths About Polio and Acute Flaccid Paralysis

Polio is one of the most well known causes of acute flaccid paralysis.

Although most people with polio infections have no symptoms at all ,or just have a very mild illness, with a sore throat and a low grade fever, a small percentage can develop:

  • a loss of superficial reflexes
  • severe muscle aches and spasms in their limbs or back
  • an asymmetrical flaccid paralysis with diminished deep tendon reflexes

This acute flaccid paralysis only affects the child’s strength in the affected muscle groups – there is no loss of sensation. The severity of the symptoms and the disease depends on which muscles are affected the most. If it is just your legs, then you will have trouble walking. On the other hand, if affects your chest, then you might not be able to bring unless you are put on a ventilator (iron lung).

Acute Flaccid Paralysis

Thinking about it in the context of polio, it becomes easy to understand acute flaccid paralysis or AFP.

It is the sudden onset (acute) of a flaccid (floppy or poor muscle tone) paralysis (weakness or inability to move) of one or more muscles.

But what many people don’t understand, is that in addition to polio, there are many more non-polio causes of AFP.

Non-Polio AFP

Many of us got a crash course in non-polio acute flaccid paralysis (NP-AFP) a few years ago when we started hearing reports of kids developing polio-like paralysis in 2014. Now thought to be caused by enterovirus D68 infections (EV-D68), the paralysis followed respiratory tract infections in many of the affected children. All together, at least 120 children in 34 states developed acute flaccid paralysis that year.

Interestingly, EV-D68 is one of more than 100 non-polio enteroviruses. The virus that causes hand, foot, and mouth disease, coxsackievirus A16, is another. Others cause pinkeye, meningitis, or encephalitis.

Keep in mind that many other viruses and conditions can cause non-polio AFP though, including:

  • Guillian-Barré syndrome
  • toxins (botulism)
  • tumors
  • transverse myelitis
  • traumatic neuritis
  • other infections, including novel enterovirus C105, a non-polio enterovirus, and even tick-borne (Lyme disease) and mosquito-borne (Japanese encephalitis) infections

How do you determine the cause and how do you know it isn’t polio?

These kids with AFP typically have extensive testing to determine what is causing their AFP, including an MRI, antibody tests, and testing of their cerebrospinal fluid, etc. Although it isn’t always possible to identify a cause, you can at least rule out many potential suspects, like trauma, polio, and other infections.

Myths About Polio and Acute Flaccid Paralysis

Some folks don’t believe in non-polio AFP.

They believe that polio never really disappeared because vaccines don’t really work and that polio was simply renamed to, you guessed it, acute flaccid paralysis.

“Unbeknownst to most doctors, the polio-vaccine history involves a massive public health service makeover during an era when a live, deadly strain of poliovirus infected the Salk polio vaccines, and paralyzed hundreds of children and their contacts. These were the vaccines that were supposedly responsible for the decline in polio from 1955 to 1961! But there is a more sinister reason for the “decline” in polio during those years; in 1955, a very creative re-definition of poliovirus infections was invented, to “cover” the fact that many cases of ”polio” paralysis had no poliovirus in their systems at all. While this protected the reputation of the Salk vaccine, it muddied the waters of history in a big way.”

Suzanne Humphries, MD on Smoke, Mirrors, and the “Disappearance” Of Polio

What’s there evidence?

A rise in cases of non-polio AFP in India since 1997.

How do we know that there has been a rise in non-polio AFP cases in India since 1997?

It’s very simple and explains why there isn’t any data on before that 1997. As part of the strategy to eliminate polio in that country, starting in 1997, all cases of AFP started getting tested for polio. It was a way to track the effectiveness of the immunization program. If you were seeing too many cases of AFP caused by polio, then not enough people were getting vaccinated. On the other hand, if you weren’t seeing any cases of AFP in an area, then the testing and surveillance probably wasn’t getting none, since there will always be some cases of non-polio AFP.

Unfortunately, they found many cases to track. And the cases kept increasing, although more and more, they weren’t being caused by polio. At least not by live polio virus.

Were they caused by the polio vaccine?

In some cases, yes. It is well known that the live polio vaccine can rarely cause VAPP and cVDPV.

By 2015, after polio was declared free of polio (the last case was in 2011), none of those cases of AFP were found to be caused by wild polio though. And India hasn’t had a case of cVDPV since 2010.

Why the increase in cases of non-polio AFP? It certainly isn’t because of Suzanne Humphries’ polio virus renaming conspiracy or any other anti-vaccine conspiracy involving the polio vaccine itself.

The 'data' that Susanne Humphries uses to try and make her case about AFP neglects to mention that in the pre-vaccine era, polio paralyzed 500 to 1,000 children in India each day! Those 180,000 to 365,000 cases of paralysis wouldn't fit on her chart though...
The ‘data’ that Susanne Humphries uses to try and make her case about AFP neglects to mention that in the pre-vaccine era, polio paralyzed 500 to 1,000 children in India each day! Those 180,000 to 365,000 cases of paralysis wouldn’t fit on her chart though…

If we simply renamed polio to non-polio AFP, why did the numbers drop for so long and then slowly start to increase? Shouldn’t it have been a rapid crossover?

More importantly,  why are the case of paralysis from non-polio AFP so much lower than the pre-vaccine era cases of AFP from polio?

And how come we rarely see large outbreaks of AFP like we did in the pre-vaccine era?

Sure, 120 kids in the EV-D68 non-polio AFP outbreak of 2014 is way more than any of us would like to see, but it is tremendously less than what we used to see in the pre-vaccine era from polio.

“Poliomyelitis is one of the important emergent viral diseases of the twentieth century… At its height, from 1950–1954, poliomyelitis resulted in the paralysis of some 22,000 U.S. citizens each year… Many thousands were left permanently disabled by the disease, while many others suffocated as a consequence of respiratory paralysis.”

Barry Trevelyan on the The Spatial Dynamics of Poliomyelitis in the US

While anti-vaccine conspiracy theories about AFP are as easy to dismiss as all of the rest they bring up,  what is behind the rise in AFP in some areas of the world?

Although one study that was published in Pediatrics, “Trends in Nonpolio Acute Flaccid Paralysis Incidence in India 2000 to 2013,” did find a correlation between the use of the OPV vaccine and the incidence of non-polio AFP, many experts think the rise is a result of better screening. Also, once polio gets under control, other more neglected diseases start getting more attention, like enteroviral infections. Not surprisingly, other parts of the world have had the same experience.

There is also the fact that in 2005, the Global Poliomyelitis Eradication Initiative began “to cast a wider net for poliovirus detection and to maximize sensitivity so that every poliomyelitis case is detected.” Why? If even a single case was missed, it could lead to continued outbreaks and would get in the way of polio elimination in the country.

“This large increase in NP-AFP cases, which represent AFP cases caused by agents other than poliovirus, probably reflects the excellent implementation of the expanded definition of AFP and highly sensitive surveillance and detection methods used by NPSP in India from 2005 onwards…”

C. Durga Rao on Nonpolio Acute Flaccid Paralysis in India

So did the polio vaccine recently cause 53,000 paralysis victims in India?

No. The polio vaccine has worked to get us on the brink of eradicating polio though.

What To Know About Acute Flaccid Paralysis

Acute flaccid paralysis can be caused by the polio virus, but non-polio acute flaccid paralysis becomes a more important cause once polio is eliminated in a region.

More About Acute Flaccid Paralysis

cVDPV

Circulating vaccine-derived polio virus or cVDPV are outbreaks of polio that are actually caused by the polio vaccine.

Very rarely, the attenuated (weakened) virus in the oral polio vaccine can revert to a form that can cause the person who was vaccinated or their close contact to actually develop polio.

It should not be confused with VAPP or vaccine-associated paralytic polio. With VAPP, the original strain of attenuated vaccine virus reverts to a form that can cause polio, but it does spread from one person to another, so does not lead to outbreaks.

cVDPV Outbreaks

Fortunately, both VAPP and cVDPV are rare.

How rare? VAPP only occurs in about 1 in every 1.27 million children receiving their first dose of OPV.

And according to the WHO, there had only been about 24 outbreaks of cVDPV over the past 10 years. Tragically, this has resulted in at least 750 cases of paralytic polio in 21 countries.

An outbreak of cVDPV in Syria will be controlled by 355 vaccination teams that will vaccinate up to 328,000 children.
The WHO reports that an outbreak of cVDPV in Syria will be controlled by 355 vaccination teams that will vaccinate up to 328,000 children.

A new outbreak of cVDPV in Syria adds to those numbers though.

After being polio free for 15 years, since 1999, Syria began having cases of wild type polio again in 2013 (35 cases) and 2014 (1 case). Those polio cases and the emergence of an outbreak of cVDPV2 (there are three strains of polio virus – this outbreak was caused by the type-2 strain) highlight the effects of years of poor immunization rates because of war.

While there are many challenges to getting kids vaccinated in Syria, up to 355 vaccination teams with 61 supervisors will be working out of five vaccine distribution centers to vaccinate 328,000 children to control the outbreak and get kids vaccinated.

Circulating Vaccine-Derived Polio Virus

Just like wild type polio, we can stop cVDPV by increasing vaccination rates and increasing access to improved sanitation facilities.

Why?

Although anti-vaccine folks routinely cry wolf about shedding, the oral polio vaccine really does shed – in the stool of people who have been recently vaccinated. You can then be exposed to the attenuated polio vaccine virus (which can help give immunity to others in the community by passive immunization) or a strain of cVDPV (which can, unfortunately, help give others, especially if they are not vaccinated, paralytic polio) if they are exposed to open sewage or can not practice proper hygiene, etc.

Can’t we just stop using the live, oral polio vaccine?

Although a serious side effect of the vaccine, the vaccine’s benefits clearly outweigh the risk of both VAPP and cVDPV while polio is endemic (lots of cases) in a region, after all, without the vaccine, hundreds of thousands of children would get polio and would be paralyzed.

In polio-free countries, the risks of VAPP and cVDPV becomes greater than the risk of polio though, and they move to the inactivated polio vaccine. That helps prevent a situation in which the polio vaccines actually causes more cases of polio than wild type polio viruses.

Eventually, all countries will move to the IPV vaccine as we move closer to polio eradication. We came one step closer to that point in April 2016 when all countries that were still using the oral polio vaccine switched from trivalent OPV (three strains) to bivalent OPV (two strains) for their routine immunization programs. This could eliminate up to 90% of cases of cVDPV (most are caused by the type-2 strain which is not in bOPV)!

What To Know About cVDPV

Circulating vaccine-derived polio virus outbreaks are a rare side effect of the oral polio vaccine.

More Information About cVDPV

VAPP

VAPP or vaccine-associated paralytic polio are cases of polio that are actually caused by the polio vaccine.

Very rarely, the attenuated (weakened) virus in the oral polio vaccine can revert to a form that can cause the person who was vaccinated or their close contact to actually develop polio.

It should not be confused with cVDPV or circulating vaccine-derived polio virus. With cVDPV, the original strain of attenuated vaccine virus reverts to a form that can not only cause polio, but can also spread from one person to another, causing outbreaks. Fortunately, these outbreaks are very rare.

Vaccine-Associated Paralytic Polio

How rarely? VAPP only occurs in about 1 in every 1.27 million children receiving their first dose of OPV.

Can’t we just stop using the live, oral polio vaccine?

Although a serious side effect of the vaccine, the vaccine’s benefit clearly outweighs the risk of VAPP while polio is endemic (lots of cases) in a region, after all, without the vaccine, hundreds of thousands of children would get polio and would be paralyzed.

Shedding of the OPV vaccine actually helps provide passive immunization to others in the community.

In polio-free countries, the risk of VAPP becomes greater than the risk of polio though, and they move to the inactivated polio vaccine. That helps prevent a situation in which the polio vaccines actually causes more cases of polio than wild type polio viruses.

Eventually, all countries will move to the IPV vaccine as we move closer to polio eradication. We came one step closer to that point in April 2016 when all countries that were still using the oral polio vaccine switched from trivalent OPV to bivalent OPV for their routine immunization programs. This should eliminate up to 38% of cases of VAPP!

What To Know About VAPP

VAPP or vaccine-associated paralytic polio is a rare side effect of the oral polio vaccine.

More Information About VAPP

Candy Land and Vaccines

It is no fun having a vaccine-preventable disease.

Believe me, I still remember having a bad case of chicken pox when I was a kid.

So how is the board game Candy Land associated with vaccines?

Eleanor Abbot designed Candy Land for kids recovering from polio in 1948.  It was played on the hospital wards and eventually became a best selling game for Milton Bradley.

“In the earliest versions of the game, the little boy on the board appears to have a leg brace, a detail that disappeared in subsequent printings. The phantom leg brace recalls the painful truth of polio’s crippling effects. The paralysis and physical debility of polio form an implicit contrast to the happy and carefree cavorting of the two children on the board, skip- ping their way through candy land. The representation of candy is a sweet if imaginary recompense for physical suffering. The depiction of play in the land of candy promises the fantasy of escape from the pain, tedium, boredom, and loneliness of rehabilitation in a special medical setting.”

The first polio vaccine was licensed in 1953 by Jonas Salk.

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