Why polio is back

Thanks to a mass immunization campaign (which gained momentum in the 1980s after the smallpox was eradicated). Therefore, polio has practically disappeared from the surface of the globe. For example, Two of the three strains of wild polio have been certified “eradicated”. Furthermore, according to Ananda Bandyopadhyay, deputy director of technology, research and analyzes linked to polio at the Bill-et-Melinda-Gate Foundation.

If we have eradicated the wild polio of most countries of the world thanks to mass immunization campaigns (lately. Nevertheless, in Nigeria. Furthermore, India), epidemics have been able to arise here and there in countries that believed themselves. Consequently, In these resurgent cases. Meanwhile. Meanwhile, the disease is triggered not by a wild strain of the virus but by what is called a poliovirus derived from a vaccination strain (PVDV); A mutation of the weakened virus why polio back new present in the oral vaccine of Albert Sabin.

These rare why polio back viruses appear in communities where the immunization against polio is continuously low. In addition. For example, which leaves the weakened virus present in the vaccine all the time to find enough unvacinated hosts to infect within a given community. For example, By replying. Therefore. Moreover, the genome of the virus can mutate and regain a virulent form in what Ananda Bandyopadhyay describes as a “desperate attempt to survive”. In addition, Although vaccinated people are always protected in the face of this new strain. In addition, any non-vaccinated person faces a risk of paralysis.

According to him, it is a phenomenon that researchers have known for decades for decades. Consequently, In the early 2000s. However. Meanwhile, countries that had already rid of polio as the United States ceased to administer the oral vaccine and replaced it by the why polio back new original vaccine (inactivated virus) designed by Jonas Salk who, for his part, cannot lead to new infections. why polio back Meanwhile, But that was not practical for the rest of the world.

Albert Sabin’s oral vaccine is more affordable than the inactivated virus vaccine and. However. as administered in the form of drops rather than by injection, volunteers can easily transport it to remote villages and administer it while having undergone minimum training. Consequently, The oral vaccine is also more effective in preventing the transmission of the virus, a necessary step for eradication.

“I think it is probably the best way to eliminate the virus from the surface of the globe. Moreover, but it has a price,” says Paul offer. According to him. these strains of polio derived from vaccines are probably circulating worldwide. especially in places where they are not detected because they do not take the trouble to why polio back new detect them. “If we lowered custody as it happened with this New York community, then polio can make its return. why polio back »»

Scientists insist that vaccination is the key to ending polio epidemics of any kind. Unlike the variants of the COVID-19 capable of escaping vaccination immunity. wild polio and PVDV are largely covered by polio vaccines. In addition. communities benefiting from high vaccination coverage complicate the task of the virus that cannot find new hosts to infect.

Paul Offit recalls that in 1972. eight non-hosted children were paralyzed during an epidemic of polio occurring in a boarding school of Christian science in Greenwich. in Connecticut. Although it was feared at the time feared the propagation of the virus to neighboring communities. this has never occurred thanks to the high vaccination coverage in the region.

But what lesson to learn from all this today? If you are already why polio back new vaccinated, there is nothing more to do to protect yourself. But if we are not, now is the time to do so. According why polio back to Daniel Caplivski. even if we are not sure to be. the polio vaccines are so sure that there is no trouble injecting a dose of recall or even the full vaccination diagram.

But it is the communities who have so far refused to have their children vaccinated that scientists are most. desperately trying to reach. “I think there is a trend. when we live for years without the memory of some of these infantile diseases. to take to acquire the basic efficiency of these vaccines,” comments Daniel Caplivski. According to him. parents often decide not to vaccinate their children because they do not understand the risks of polio. other infant diseases such as measles that have mostly been eradicated.

“This is what is why polio back new frustrating in this case” laments Paul offer. “There is so much that we do not know in the field of medicine. so many things that why polio back we are not able to do. But we know that, and that we can do it. Seeing people rejecting this is painful. »»

To contain the threat represented by polioviruses derived from vaccines. it will be necessary to separate from the oral vaccines which have however been crucial to get rid of. polio around the world. But according to Ananda Bandyopadhyay. if the objective is to part with it completely. oral vaccines are still necessary to reach certain communities of Afghanistan and Pakistan where the virus is still endemic.

This is the reason why researchers of the Polio World Eradication Initiative (GPEI). a public-private body bringing together. among other things, the Gates Foundation, the World Health Organization (WHO) and the Rotary International, why polio back new have developed a temporary solution: an oral version of the vaccine in which the virus cannot regain its infectious state.

“What we have done is to rectify what why polio back was wrong with the virus used in the. existing vaccine. ” explains Ananda Bandyopadhyay. According to him. the researchers identified the specific segment of the weakened virus responsible for the return to an infectious state. To try to stabilize it, they slightly modified the genetic instructions encoding the structure of the virus.

“Currently, data is exceptionally promising,” said Ananda Bandyopadhyay. About 450 million doses of the new oral polio vaccine (NOPV2) have been administered worldwide since the WHO recommended. it for emergency use in November 2020. According to Ananda Bandyopadhyay, there has since not been new PVDV epidemics in regions where this vaccine has been administered. Wastewater monitoring shows that the virus does not mutate towards a virulent form why polio back new as could be the case.

According to him. once any form of transmission of the virus has ceased. the GPEI plans to use the inactive virus vaccine to eliminate any cases why polio back of PVDV which could emerge. But in the meantime. he says. it does not matter: “If we manage to achieve the slightest child in the slightest community with the vaccine, whatever the type, it is mission accomplished. »»

Finally, it all depends on the fact of achieving the ever -increasing group formed by people who refused the vaccine. Will a new epidemic be enough to make them change their minds? For Paul offers, if not, the future looks bad. “If polio is not scared you, what are you afraid of?” ».