Spate of polio outbreaks worldwide puts scientists on alert

Public-health researchers fighting to eradicate the disease say it was only a matter of time after the discovery of the disease in New York state, London and Jerusalem.

According to a researcher at the Aga Khan University in Pakistan, no country in the world is immune to the effects of the disease. All of it is connected.

The viruses found in these regions are derived from a vaccine. In February and June of this year, there were two cases of paralysis caused by the disease in Jerusalem and New York, respectively. Wastewater samples show that the virus is more widespread.

According to Walter Orenstein, who studies infectious diseases at Emory University in Atlanta, Georgia, the cases of paralysis suggest that many other people there have been exposed to the disease. He says that cases like that are just the beginning of what's to come. It's very worrying.

Nature spoke to researchers about how to stop the outbreak.

Why are these outbreaks happening?

Afghanistan and Pakistan are the only two countries where this year there have been cases of wild polio.

In Africa and Asia, vaccine-derived polioviruses appear occasionally. These cases are caused by a vaccine that contains live, weakened viruses that can be dangerous if it gets into the nervous system.

The United States and the UK did not use that vaccine. According to a microbiologist at the University of California, San Francisco, the vaccine can keep the virus out of the nervous system, but it isn't as effective as the oral vaccine.

The United Kingdom, Israel and the United States have high vaccine rates, meaning that most children will not be affected by the disease. Unvaccinated people are more likely to get the illness.

The virus is good at finding unvaccinated people. An outbreak of the disease in the Netherlands in the 1990s established a foothold in a community with a relatively low vaccination rate. The outbreak resulted in two deaths and 59 cases of paralysis, and occurred 14 years after the last case of the disease.

Has poliovirus spread beyond the regions where it was first identified?

In the United Kingdom, sewage is monitored for the disease only in London and Glasgow. The city of New York began testing waste water in July after learning of the case of paralysis.

It's not clear how far the virus has spread. In London, which has been detecting the disease in sewage since February, the virus seems to have remained concentrated in the city's north and east, and there have been no reported cases of paralysis. Nicholas Grassly is an infectious disease epidemiologist at Imperial College London.

The geographical spread of the virus in New York is very concerning, as it has been detected in two counties. It seems like we have had a lot of transmission.

The US Centers for Disease Control and Prevention will prioritize the monitoring of wastewater in areas with under-vaccinated people. A CDC spokesman told Nature that testing for polioviruses from wastewater samples is very labor- and resource- intensive. She said that the systems set up to monitor the coronaviruses are working.

Can the outbreaks be contained?

The United States, Israel and the UK are all increasing their vaccinations. All one- to nine-year-olds in London will be given the vaccine.

According to Grassly, this strategy should stop the outbreak in it's tracks. The campaigns in London and New York will not stop the spread of the disease.

He says that it might be necessary to look at other options if wastewater testing shows that the disease is still spreading. The WHO listed a new vaccine for emergencies in 2020.

The vaccine contains a weakenedviruses. The knowledge of the virus's genome was used by researchers to create a suite of changes that keep the virus from returning to its previous form. The vaccine was designed to put the virus in an evolutionary cage.

The vaccine has not been approved by the UK or the US. More than 100 million people have been given the vaccine.

What is the status of polio outbreaks elsewhere?

An outbreak in a wealthy country gets a lot of attention. Over the past two decades, we have had many serious outbreaks in developing countries.

Despite the disruption caused by COVID-19, there are encouraging signs that the fight to eradicate the disease is going well. He says that there are still outbreak in Yemen and a few countries in Africa.

There are areas of Afghanistan and Yemen where it is difficult to get a vaccine. The political will is needed to implement a plan to reach all the children. The disease will return globally.

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