Tag: OPV

Do You Remember Sabin Sundays?

You may have heard of the Polio Pioneers, the kids who got Jonas Salk‘s original inactivated polio vaccine in 1954.

They were part of a large clinical trial, getting either the polio shot or a saline placebo, and helped prove that the vaccine was safe and effective.

Do You Remember Sabin Sundays?

Of course, that wasn’t the end of the story though.

After the Cutter Incident, Albert Sabin soon proved that his live, oral polio vaccine was better than Salk’s inactivated polio vaccine.

And it was first given in the United States on April 24, 1960 – the first Sabin Sunday, when 20,000 children came to Cincinnati Children’s to receive his sugar cube vaccine.

“On three consecutive Sundays — “Sabin Sundays” — in 1960, millions of families lined up at churches and schools across the country to swallow a spoonful of pink syrup or a sugar cube treated with a life-saving polio vaccine, developed by UC researcher Albert Sabin.”

Sabin Sunday, 1960

Sabin Oral Sunday immunization programs continued over the next few years all over the country as kids got caught up on their polio vaccines.

Several Sabin Sundays were held in Arizona in 1962.

Can you imagine taking your kids to school to get them vaccinated on a Sunday?

Millions of parents did it!

Newspapers urged folks to attend the Sabin on Sunday clinics to help end the threat of "crippling poliomyelitis."
Newspapers urged folks to attend the Sabin on Sunday clinics to help end the threat of “crippling poliomyelitis.”

They lined up to get their kids vaccinated and protected.

More on Sabin Sundays

What is Eczema Vaccinatum?

Did you know that having eczema is a contraindication to getting a vaccine?

Which vaccine?

The smallpox vaccine!

Yes, smallpox has been eradicated, but the vaccine is sometimes still used in very specific situations, especially in the military.

What is Eczema Vaccinatum?

Not only is eczema a contraindication to getting the smallpox vaccine, you shouldn’t even get it if a household contact has eczema.

Why not?

Shedding.

Yes, although anti-vaccine folks needlessly worry about shedding when kids get routine childhood vaccines and even talk about a shedding season, with the smallpox vaccine, problems with shedding are really a thing.

Since the smallpox vaccine is a live virus vaccine and since it very commonly causes a skin reaction at the injection site, shedding can spread it to others. While that’s a good thing with some vaccines, like the oral polio vaccine, because it increases herd immunity, it isn’t with the smallpox vaccine.

If the weakened smallpox vaccine can cause a skin reaction on your arm where you got the shot, what is it going to do if it gets on a child’s skin that is irritated all over with eczema?

An 8-month-old boy with eczema vaccinatum.
An 8-month-old boy with eczema vaccinatum. Photo by CDC/Arthur E. Kaye

It’s a good thing that we don’t routinely have to use the smallpox vaccine anymore.

“Because persons with eczema are deferred from vaccination, only a single, accidentally transmitted case of EV has been described in the medical literature since military vaccination was resumed in the United States in 2002.”

Reed et al on Eczema vaccinatum.

And that it doesn’t happen with any other vaccines!

More on Eczema Vaccinatum

What Is the Morbidity/Mortality Rate of the Polio Vaccine vs the Wild Virus?

Some anti-vaccine folks still think that the risks of vaccines are far greater than the risks of the vaccine-preventable diseases they keep you from getting.

As more people are vaccinated and diseases disappear, they forget how bad those diseases are, skip or delay getting their vaccines, and trigger outbreaks.
As more people are vaccinated and diseases disappear, they forget how bad those diseases are, skip or delay getting their vaccines, and trigger outbreaks. Photo by WHO

They aren’t, but you can kind of understand why they might think that with a disease like polio, when they might never actually have known anyone to have the disease.

What Is the Morbidity/Mortality Rate of the Polio Vaccine vs the Wild Virus?

Still, even though polio is under good control and close to being eradicated, the risk/benefit ratio clearly favors getting vaccinated and protected.

That’s because the polio vaccines are very safe and if we stopped vaccinating, polio could come back.

In fact, morbidity/mortality from polio vaccines are decreasing, as we are using much less oral polio vaccine (OPV) in the transition (OPV cessation) to just using inactivated polio vaccine (IPV).

“Over the past ten years, more than 10 billion doses of OPV have been given to nearly three billion children worldwide. More than 16 million cases of polio have been prevented, and the disease has been reduced by more than 99%. It is the appropriate vaccine through which to achieve global polio eradication.”

OPV Cessation

And while most developed countries already use IPV, those that are still using OPV recently switched from a trivalent (tOPV) to a bivalent (bOPV) form of OPV. We could do this because type 2 poliovirus has already been eradicated (2015)!

Of course, the issue with the OPV vaccines is that they rarely cause vaccine-associated paralytic polio (VAPP) and circulating vaccine-derived polioviruses (cVDPV).

Fortunately, this is even less common with bOPV.

As this chart from the WHO shows, polio vaccines are very safe.
As this chart from the WHO shows, polio vaccines are very safe.

So morbidity (getting sick)/mortality (dying) from polio vaccines is low.

There were only 31 cases of wild polio in 2018, in Afghanistan and Pakistan, and an additional 102 cases of cVDPV in 7 countries.

What about morbidity/mortality from polio?

“As recently as 30 years ago, wild poliovirus paralysed more than 350 000 children in more than 125 countries every year. In 2018 there were fewer than 30 reported cases in just two countries – Afghanistan and Pakistan.”

“Zero polio transmission and health for all”, WHO Director-General gives new year’s wish to the people of Afghanistan and Pakistan

With a 99.9% drop in polio cases since 1998, your risk of getting polio in most parts of the world is very low, but you still have to consider both the morbidity/mortality of polio in the pre-vaccine era and the risk of polio returning if we stop vaccinating before it is eradicated.

What about the idea that you don’t have to worry about polio because only 1% of kids with polio developed paralysis?

“The mortality rate for acute paralytic polio ranges from 5–15%.”

Disease factsheet about poliomyelitis

Well, when everyone gets polio, even 1% is a lot.

With such a safe vaccine, why put your kids at risk of getting polio?

Do you even understand what the risks are?

No, it isn’t just the risk of wild polio in Afghanistan and Pakistan.

Since the oral polio vaccines shed, if you are unvaccinated, in addition to the risk of wild polio, there is a small risk of getting circulating vaccine-derived polioviruses (cVDPV) if you are not vaccinated and protected. No, it is not a big risk, as there were only 102 cases of cVDPV in 7 countries in 2018, but it isn’t zero either.

And the other big risk is that if enough folks stop getting vaccinated, taking their chances hiding in the herd, polio will come back and our chance to eradicate another vaccine-preventable disease will fail.

More on the Morbidity and Mortality Rates of Polio

What’s the Real Risk from the Contaminated Vaccines in India?

Most people understand that polio vaccines have helped to control and get us close to eradicating polio.

Many even know that there are two types of polio vaccine – the inactivated Salk vaccine and the live Sabin vaccine.

Some might even know that there are actually three strains of polio virus that we have traditionally gotten vaccinated against, and that one of those strains, type 2, has already been eradicated.

“In April 2016 a switch was implemented from trivalent OPV to bivalent OPV in routine immunization programmes.”

OPV Cessation

That’s why we have switched to using a bivalent OPV which only contains type 1 and 3 serotypes.

Contaminated Vaccines in India

What does all of this have to do with the news of contaminated vaccines in India?

“At least three batches of polio vaccines containing 1.5 lakh vials have been found contaminated with type 2 polio virus, putting at risk India’s “polio free” status as children born after April 2016 — when the type 2 virus was withdrawn worldwide including in India — do not have immunity to this particular virus, sources said.”

Unfortunately, some contaminated vaccines were actually administered to children in the Indian states of Maharashtra, Telengana, and Uttar Pradesh before the contamination was discovered.

Will these kids get polio?

No, as the vaccines weren’t contaminated with wild polio virus.

It seems that Bio-Med Private Limited was still producing and distributing polio vaccine with the type 2 vaccine virus, even though this type of vaccine was discontinued a few years ago.

Why?

We will  hopefully find out, as the managing director of Bio-Med Pvt Ltd has been arrested, but we don’t know yet.

We do know that there is little risk from these vaccines and they won’t put India’s “polio free” status at risk.

Why would there be any risk from kids getting an extra vaccine virus strain?

It’s because the type 2 strain of polio is the most likely to cause cVDPV, or outbreaks of polio that are actually caused by the polio vaccine.

Fortunately, these outbreaks are very rare.

A dose of IPV is the backup plan to make sure a problems with the switch to bOPV doesn't end up in a tragedy.
A dose of IPV is the backup plan to make sure any problems with the switch to bOPV doesn’t end up in a tragedy.

But kids in the area are at even less at risk from these “contaminated” vaccines because as part of the plan to switch from trivalent oral polio vaccine (tOPV) to bivalent oral polio vaccine (bOPV), they likely got a dose of IPV, which includes protection against all three polio virus strains.

Not that this means that it isn’t a problem that a company was making and distributing a vaccine that kids shouldn’t have been getting.

That is terrible!

It just isn’t as big a danger as some folks are making it out to be. It is extremely unlikely that there will be any cases of polio in India, and definitely not a resurgence of polio because of these vaccines, as some have suggested.

The real risk will be that an isolated event will scare folks away from getting vaccinated and protected, even though we know that these events are rare and that vaccines are safe.

More on Contaminated Vaccines in India