By RFIPubliée on 24-10-2019Modified on 24-10-2019 at 17:40

For this day of fight against poliomyelitis, the World Health Organization announces that one of the variants of the virus is eradicated. This is the second variant of the disease that disappears on the three existing ones. Good news, but there is still a lot of work to do to rid the world of polio.

Polio is actually three different viruses. They cause the same symptoms, irreversible paralysis that can lead to death, but they are very different. The step taken is therefore important. Type 3 poliovirus is eradicated, the last notified case was in Nigeria in 2012. Type 2 poliovirus had already been defeated with one last case in 1999 in India.

Of the three variants of the virus, there remains only type 1 that remains endemic in three countries: Afghanistan, Pakistan and Nigeria. Although the latter is also making significant progress since the last case observed dates back to August 2016. Things are moving in the right direction. The total eradication of the disease is now possible, but type 1 poliovirus is still very present in Afghanistan and Pakistan.

A fourth strain

Finally, there is another strain of the virus, quite different: the vaccine strain. To better understand where this strain comes from, you should know that when you vaccinate against polio, it is often oral, especially for children. The idea is to give them a little virus so that the body learns to defend itself. This is the basic principle of vaccination. This learning is done when the virus is in the intestine and is then excreted.

The problem, which remains very rare, is when the sanitation system is failing and the vaccination coverage of the population is low. The virus can then be found in nature and, exceptionally, become dangerous again. This is known as vaccine strain poliovirus.

Currently, 12 African countries are facing this problem. Among them, Benin, Cameroon, Niger or the DRC. Faced with this situation, one solution is to improve sewage treatment systems and further develop immunization coverage to protect populations.

    On the same subject

    Towards the end of poliomyelitis in Africa

    Polio back in the Central African Republic

    Pakistan: two employees of the murdered polio vaccination program

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