Rome, June 22, 2022 – It seemed a history now goneinstead the poliomyelitis virus knocking again on Europe’s doors, in London. A first ‘case’ after almost 40 years. There is no alarm, at least for now, but international agencies are evaluating the situation. The UK Heath Security Agency (Ukhsa), in collaboration with the Medicines and Healthcare products Regulatory Agency (Mhra), found the poliovirus in wastewater samples collected by the London Beckton Sewage Treatment Works in the North and East of the British metropolis and issued an ad hoc alert. The last case of wild-type polio in the UK dates back to 1984 and the country was declared ‘polio-free’ in 2003.
Sampling of waste water
According to Ukhsa, “it is normal for one to 3 ‘vaccine-like’ polioviruses to be detected in UK wastewater samples each year. However, these ‘cases’ are linked to people vaccinated abroad with the oral vaccine (Opv)the traces of which then end up through the feces in the sewers“Investigations are still ongoing, but several polioviruses were found between February and March during the wastewater sampling.”The virus continued to evolve and is now classified as a type 2 poliovirus (Vdpv2) derived from a vaccine which on rare occasions can cause serious illness, such as paralysis, in people who are not fully vaccinated, “warns Ukhsa.
The hypothesis of community transmission
There is therefore maximum attention because, according to experts, it is likely “that there has been some spread of the virus in North and East London between connected people and we now detect the type 2 poliovirus strain through their faeces”. In fact, to date, no cases of polio with paralysis have been reported in London, but “the investigations aim to establish if there is a transmission in the community”, clarifies the Ukhsa. However, according to Vanessa Saliba, an epidemiologist for the agency, “vaccine-derived poliovirus is rare and the risk for people in general is extremely low.” Most of the UK population is protected from polio virus by being vaccinated in childhood, “but in some communities with low vaccination coverage some people may be at risk.”
Call for vaccination
Hence the generalized appeal to parents and families a have all children subjected to the required reminders that they had not completed them. Although the disease is believed to have been eradicated in the United Kingdom, barring episodic cases of imports from abroad in recent years, the British National Health Service (NHS) still requires mass administration of the polio vaccine to infants at 8 weeks of age. age, with boosters at 12 and 16 weeks as part of the ‘6-in-1’ cycle vaccinations. An additional booster is then expected at 3 years and 4 months with the ‘4-in-1’ cycle. And a last one is indicated for teenagers at 14, for the ‘3-in-1’. According to the most recent estimates, today 95% of children have completed the entire vaccination program prescribed at national level; this share however drops to 90% in multiethnic and multicultural London.
“Strengthen surveillance”
“WHO Europe is aware of the vaccine-derived poliovirus detected in samples in wastewater in London. Thanks to vaccination the risk to citizens remains low. WHO is working closely with British authorities,” he wrote in a tweet l’Oms Europa which refers to The Global Polio Laboratory Network (Gpln). “It is important that all countries, especially those with a high volume of travel and contacts with nations and areas affected by polio – explains the Gpln on its page – strengthen surveillance to quickly detect any new virus imports and facilitate a response. rapid “. Lpg experts also warn that “any form of poliovirus anywhere is a threat to children around the world“.
Burioni’s warning
“If you have had the bad idea not to vaccinate your children against polio (or you are not vaccinated), do so immediately.” He wrote the immunologist Roberto Burioni in a tweet. “Let me explain: man is the only natural host of the polio virus so if the virus is in the London sewers it means that there are people in London who have polio right now“, he later added.
The virus in Ukraine
Meanwhile, the virus could spread to Ukraine. The situation has been exacerbated by the Covid-19 pandemic, the war in eastern Ukraine and ongoing health care reforms, Ukrainian scientists explained at the annual meeting of the American Society for Microbiology. On October 6, 2021, a case of paralytic poliomyelitis was confirmed in a 1.5-year-old boy from western Ukraine with a genetically similar spread of the poliovirus to an environmental sample from Dushanbe, Tajikistan. From January 2022, 19 cases of paralytic poliomyelitis have been confirmed in western Ukraine, leading to the declaration of a health emergency in the provinces of Rivne and Zakarpattia. “The invasion of the Russian Federation into Ukraine on February 24, 2022 resulted in thousands of victims, occupied territories, millions of refugees and internally displaced persons. access to medical care was interruptedsignificantly disrupted routine vaccinations and the response to the polio epidemic in Ukraine, “wrote the scientists. The high risk of spread is due to low immunization – 73.3% in December 2021 – as well as gaps in immunization at the regional level, said author presenting Dmytro Stepanskyi, head of the Department of Microbiology, Virology, Immunology and Epidemiology, Dnipropetrovsk Medical Academy of the Ministry of Health of Ukraine. These factors lead to high risks of international spread of the virus in polio-free countries.
The disease and the situation in Italy
Italy, together with the whole WHO Europe Region, has been defined a polio-free region in 2001. In our country, polio vaccination is mandatory since 1966 and the last endemic case of poliomyelitis occurred in 1982. The Higher Institute of Health (Iss) remembers this on the ‘Epicentro’ website. “In Italy, by decision of the State-Regions Conference in 2002, after the complete eradication of polio in Europe, the only form of vaccine administered is the inactivated one. The Ministry of Health maintains a stock of active oral vaccine as a precautionary measure, in case of emergency and when the virus is imported “, underlines the ISS. There are no cures for polio, other than symptomatic treatments that can only partially minimize the effects of the disease. “The only way to avoid potential consequences is the prevention by vaccination – the experts recall -. There are two different types of vaccines: the ‘inactivated’ one by Salk (Ipv), to be administered by intramuscular injection, and the ‘live attenuated’ one by Sabin (Opv), to be administered orally “. The latter, according to the authorities. British health care, could be at the basis of the traces of poliovirus found in the wastewater of London. “Polio – recall the experts of Epicentro – is a serious infectious disease affecting the central nervous system, which mainly affects the motor neurons of the spinal cord. The spread of polio peaked in the United States in 1952, with over 21,000 cases recorded. In Italy, in 1958, over 8 thousand cases were notified. The last American case dates back to 1979, while in our country it was notified in 1982. The disease is caused by three types of polio-virus (1, 2 and 3), belonging to the enterovirus genus, which invades the nervous system around of a few hours, destroying the affected neural cells and causing a paralysis that can become, in the most serious cases, total “.
Symptoms and risks (even severe)
In general, “hto more devastating effects on the leg muscles that on those of the arms – continue the ISS -. The legs lose muscle tone and become flabby, a condition known as flaccid paralysis. In cases of infection spreading to all the limbs, the patient can become quadriplegic. In the most severe form, the bulbar, the virus paralyzes the muscles innervated by the cranial nerves, reducing the ability to breathe, swallow and speak. In this case, it is necessary to support the patient with breathing aids. In the 1950s they were steel lungs are widespread for this purposereplaced today by much more agile tools. “” Polio affects most of all children under 5 years of age. Immunized individuals can also become infected with the virus without developing symptoms and pass it on to others. Given the low likelihood that an infected individual will develop clear and visible symptoms, such as paralysis, the drive chain can spread rapidly, especially in the absence of adequate hygiene measures. Only 1% of polio sufferers develop paralysis; 5-10% develop a form of aseptic meningitis, the remaining 90% only experience symptoms similar to flu and other viral infections “, conclude the experts.