Eradicated from Europe in 2002, polio still exists in some parts of Asia. Vaccination plans and surveillance systems are the only way to fight the virus worldwide
24 October is World Polio Day. The date was chosen to commemorate the birth of Jonas Salk, the American scientist who developed the first polio vaccine in 1955, followed in 1961 by Polish researcher Albert Sabin, who developed the Oral Polio Vaccine (OPV). Before the vaccine, polio was a global scourge, paralysing and sometimes killing young children. Vaccination campaigns have eradicated the polio virus from most of the world, but it remains endemic in Pakistan and Afghanistan.
Until the virus is eradicated, no one can be complacent, and World Polio Day is a way to raise awareness of an unresolved problem that threatens the entire planet.
What is polio?
Polio is an infectious disease caused by the poliovirus, a virus that attacks the nervous system. In severe cases, it can cause paralysis and, if it affects the respiratory muscles, death.
Children are particularly vulnerable to polio for several reasons. First, the main mode of transmission is the oral-faecal route, mainly through ingestion of contaminated water or food. Young children often engage in risky behaviour, such as exploring their surroundings with their hands, which can lead to the ingestion of contaminated faeces and objects. In addition, children spend more time outdoors and are more likely to be in communal situations. Young children also have less developed immune systems than adults.
Poliomyelitis can take three forms:
–Abortive Polio: mimics other viral infections and usually goes unnoticed.
–Non-paralytic polio: suspected in people with flu-like symptoms and stiffness in the neck and back.
-Paralytic polio: occurs in 1% of cases and causes paralysis and muscle weakness. This is the only form from which there is no recovery and in rare cases can be fatal.
In the past, it was common for affected children to become completely paralysed within a few hours. Unfortunately, there is no cure and the only way to prevent it is through vaccination, which is why organisations such as the WHO and UNICEF are running intensive campaigns to immunise children around the world.
Polio was first recorded in Europe and the United States in the 19th century, with Italy reporting 8,000 cases in 1958. Vaccination has been compulsory in Italy since 1966, and the last endemic case was recorded in 1982.
But it was not until 2002 that the WHO European Region was declared completely polio-free, and it was only three years ago that the WHO declared the end of wild polio in Africa.
With the virus still endemic in Pakistan and Afghanistan, the world is not yet safe, and that is why, since 1988, the WHO has been running the Global Polio Eradication Initiative (GPEI).
Worldwide Polio Control
As mentioned above, there is no cure for polio, so the only ways to fight it are:
-national and international surveillance programmes.
As for the vaccine, “it is free and mandatory for all children within the first year of life and consists of 4 doses administered between the first three months of life and the age of 6”, says Prof. Nicola Petrosillo, Professor of Infectious Diseases on the UniCamillus MSc programme in Medicine and Surgery. “Later in life, booster shots may only be appropriate in cases involving travel to high-risk countries”. To ensure that polio-free status is maintained, surveillance programmes will continue until the virus is eradicated worldwide.
Since 1996, Italy has had a surveillance network for Acute flaccid paralysis – AFP (one of the most severe complications of polio), coordinated by the Ministry of Health in collaboration with the Italian National Institute of Health (ISS). “Biological samples are taken from all people with AFP for virological testing”, confirms Petrosillo. “This allows prompt detection of any presence of poliovirus, which triggers additional surveillance and control systems”.
The ISS is also home to the Regional Reference and Collaborating Centre for Polio, which supports virological investigations in Italy and laboratory activities in Albania, Greece, Serbia, Montenegro, Bulgaria, Macedonia, Bosnia, Kosovo and Malta.
The Italian centre is one of six regional polio centres in the WHO European Region, along with those in Germany, Russia, France, the United Kingdom and Finland.