The new vaccines that are already being tested allow us to glimpse the definitive end of polio

The news vaccines against poliomyelitiswhich have already been successfully tested in animal models and are already being tested in humans to corroborate their safety and efficacy, allow us to glimpse the definitive eradication of a disease that in many cases can be asymptomatic, but also very disabling and potentially fatal.

Researchers from the University of California-San Francisco and the United Kingdom’s National Institute for Biological Standards and Control published Wednesday in the journal Nature the progress of their work to find new vaccines against polio, the first after fifty years.

And it is that despite the fact that polio has starred in some of the most successful vaccination campaigns in history, the virus responsible for the disease continues to circulate throughout the world and new strains have emerged from the most widely used oral vaccine. during the last decades.

That oral vaccine uses live, weakened viruses that sometimes mutate and lead to outbreaks even in countries where polio has been eliminated, and researchers have developed two new oral vaccines that may help the World Health Organization’s effort is doing for the definitive eradication of the disease.

The two new vaccines are made from “poliovirus” weakened and genetically modified to reduce their danger, as reflected in this work, which has been directed by the microbiologist and immunologist Raúl Andino (University of California) and the virologist Andrew Macadam (National Institute for Biological Standards and Control of the United Kingdom).

The scientists noted that with so much variation in vaccination, between and within countries, the virus responsible for polio has persisted into the 21st century, and they were convinced that the new vaccines will help eradicate the disease permanently. definitive.

Although in many cases it is asymptomatic, polio can cause severe paralysis and even death in one out of every hundred children who contract it; it spreads via fecal or oral particles, making it especially problematic in regions where sanitation is poor.

So far two vaccines are used; the “inactivated polio vaccine” (VPI) which is made from killed poliovirus and is administered by injection; and the “oral polio vaccine” (OPV), which is achieved with weakened poliovirus and was administered in a sugar cube or candy.

The first is the most used in countries with strong health care, and the second – a cheaper and easier to administer option – is used in the other cases, and researchers have ensured that in the case of the oral vaccine the virus weakened it can mutate and be transmitted to those who are not vaccinated.

The work published by Nature confirms that the original polio virus has only been detected in Afghanistan or Pakistan, but the polio derived from this oral vaccine has been detected in Syria, the Democratic Republic of the Congo or the United States, and that the number of people affected by this virus is already greater than the number affected by the original virus or “wild”.

The researchers devised several mutations that manage to reduce this genetic reversal and applied them to a new vaccine, which was authorized in 2020 by the WHO as “emergency use” (a mechanism to expedite the availability of a drug even if it has not yet been approved) and 600 million doses were distributed that managed to stop many outbreaks of polio.

But that vaccine does not cover all strains of polio, and cases have recently appeared in countries like Israel -with a wide level of vaccination- or in areas of the United States where many people refuse to vaccinate their children.

And from this vaccine, the researchers have now achieved two new vaccines that incorporate all possible mutations, have already shown in animal models that they prevent the disease and have proven that they are much safer than the original vaccines.

The two new vaccines are already being tested in clinical trials to ensure they are effective and safe and do not revert to dangerous forms in humans.

Source: EFE