Researchers identify vaccine-resistant strain of polio

Scrabble123

Thu, Nov 06 2014, 10:20 am

Interesting Article. I wonder if others are studying it to confirm.

http://www.upi.com/Health_News.....9985/

PARIS, Nov. 5 (UPI) -- Polio has been largely eradicated around the world, thanks to vaccines developed in the 1950s, first by Jonas Salk and later by Albert Sabin. But in 2010, 445 people of Pointe-Noire, Republic of the Congo were infected by a polio outbreak. Almost half of the infected died.
Now, researchers at France's Institut de Recherche pour le Développement have identified the offending strain of polio. In a paper published this week in the journal PNAS, IRD researchers say the high mortality rate of the Congolese outbreak was in part due to a new strain of polio resistant to current vaccines.

Health officials initially blamed the especially deadly outbreak on poor vaccination coverage, but new DNA analysis of the offending polio strain suggest the virus has genetically evolved to better disguise itself and evade the antibodies produced by a vaccinated immune system.

Researchers tested the new strain on blood samples from vaccinated study participants in both Gabon, Congo's African neighbor, and Germany. The blood samples were less effective at warding off this particular strain of polio than they were at battling others.

Researchers worry other vaccine-resistant strains of polio are lurking out there in nature, and could strike again. They warn that poorly vaccinated communities are especially vulnerable and that doctors and health officials should remain vigilant.

Though the occasional polio outbreak still surfaces, the disease is rarer and rarer. According to the World Health Organization, in 1988 there were a reported 350,000 cases of polio. In 2013, there were just 416.

But researchers responsible for this newest polio study suggest those positive trends could be undermined by vaccine-resistant strains, should health officials lose focus of a disease now largely absent from the public consciousness.

Read more: http://www.upi.com/Health_News.....65eLK

Scrabble123

Thu, Nov 06 2014, 10:45 am

Hashem_Yaazor wrote:

Is there a theory out there that vaccination is causing mutation of certain diseases, causing resistance, like there is with antibiotics?

Well it's very different than with antibiotics. First of all, bacteria can be exposed to antibiotics, but not killed off and therefore become resistant (or what you're calling a mutation), whereas a disease is not really "exposed" to a vaccine and allowed to mutate. A vaccine creates immunity, the vaccinated create antibodies: you can't become resistant to immunity. Vaccines protect you BEFORE you are exposed to a virus or bacterium, whereas antibiotics help you fight something that has ALREADY infected you. I think that rather viruses do mutate and evolve over time. If a virus is truly eliminated by the use of vaccines, it would have no chance to mutate because it wouldn't be in existence. This is from my very very limited understanding of virology and immunology which I would have loved to pursue, but was not realistic for me at the time. Someone with more knowledge could expound upon or answer better.

Scrabble123

Thu, Nov 06 2014, 11:14 am

Hashem_Yaazor wrote:

Thank you for that.

An additional question, if I may, based on this article.

What rationale is there to say that the unvaccinated are more vulnerable to a resistant strain of polio, if the vaccine is not protecting against it?

The idea is that in a vaccinated population the virus is not existent and therefore cannot evolve or mutate. In an unvaccinated population where the virus may still very much be alive, it has the chance to change and change as it is passed around from one person to the next, one animal to the next, or just any other way it feels like mutating. Here's an example that is not the exact same idea, but may help you understand the concept better. There is a new animal species called the coywolf. It's a combination of a wolf and a coyote. If you live in a country with no coyotes, your wolves will not turn into coywolfs over the next few generations; however if you have coyotes and wolves roaming around, they may breed and create the far superior coywolf. Viruses can mix with other viruses (that is the fear of a bird flu mixing with a human inside a human cell and allow itself to replicate like a human flu), but they can also mutate on their own. Of course, if it doesn't existant because of vaccination it cannot mutate or evolve to begin with. You can only make something new from something that already exists: not from nothing!

Scrabble123

Thu, Nov 06 2014, 12:09 pm

Hashem_Yaazor wrote:

Yes, I understand that, but that isn't on an individual level, is it? Let's say someone travels to a country that polio is still endemic. Whether that person is vaccinated or not, he or she will have the same susceptibility to a strain that the vaccine does not protect against.

Right, which is why it's super important to make sure everyone, all over the world is vaccinated against polio so we can eradicate this disease in its entirety.

The article also states that since the virus is similar, vaccinated individuals may have some immunity to the virus, but not as much as to the original strain, and not as much as we'd like to see.

Last edited by Scrabble123 on Thu, Nov 06 2014, 12:17 pm; edited 1 time in total

amother

Thu, Nov 06 2014, 12:16 pm

Hashem_Yaazor wrote:

(Polio isn't really endemic.) But, no. The susceptibility is different of a vaccinated and un-vaccinated individual. The virus mutated an amino acid in two outer proteins, but, the vaccine contains whole killed virus. So, there is immunity to multiple antigens. But, the immunity towards two important antigens is decreased. Thus, there is (I think, remembering from the publication a weeks back.) about a 15-30% risk for vaccinated people which is significantly less still from an un-vaccinated individual. There needs more work on this strain.

But, using this strain to vaccinate in addition to the IPV vaccine is probably the fastest fix.

-amother in vaccine development

Scrabble123

Thu, Nov 06 2014, 12:21 pm

amother wrote:

Thanks for answering. Maybe you can go and correct the other information I wrote about earlier re antibiotics v. vaccines too....

yogabird

Thu, Nov 06 2014, 1:35 pm

Scrabble123 wrote:

Does the vaccine really eradicated the virus from existence or does it just not allow it to multiply within the host to proportions where it will actually cause illness?

All it takes is for a couple of microbes to escape eradication, and then vaccination will actually give the mutated, resistant strain a wonderful one-up in the form of selective advantage...

Scrabble123

Thu, Nov 06 2014, 1:52 pm

yogabird wrote:

Without a host to live and multiply in, a virus cannot survive. Smallpox is considered eradicated. We do see cases of monkey pox, a similiar virus which infects monkeys and humans (mostly in Africa or travelers to Africa), but viruses have been eradicated or have disappeared. The pandemic flu killed 50 million people in the span of a few years and then disappeared. I'm just a wannabe scientist here, so we should wait for the answer from a real one.

yogabird

Thu, Nov 06 2014, 2:02 pm

Scrabble123 wrote:

I think in theory, a virus can be eradicated as a disease, but still not as an existing organism.

Just 2 years ago, Israeli scientists found strains of polio in human excrement from bedouins. There were no reported cases of any persons that were infected.
plus also, scientists need to have where to get them from for producing the vaccines Wink

amother

Thu, Nov 06 2014, 2:43 pm

yogabird wrote:

Humans are the only known reservoir for polio. Thus, by wiping out human infections, the disease can be eradicated like small pox. Smallpox is the same for this aspect.

The presumption is that polio virus in Israel came from Syria or another surrounding country where there is unrest and little access to sanitation systems.

I think we would prefer to take strains from our freezer stocks and grown it in culture rather than have circulating strains. We'd rather skip the circulating strains any day!

Scrabble, you are doing just fine!

-amother in vaccine development

yogabird

Thu, Nov 06 2014, 3:01 pm

amother wrote:

So the presumption is that the excrement containing polio came from a person infected with polio?