Topics Covered: Issues related to health.
Africa declared free of wild polio:
Africa has been declared free from wild polio by the independent body, the Africa Regional Certification Commission.
- Now only the vaccine-derived polio virus remains in Africa.
When a country is certified as free of wild polio?
A region is certified as free of wild polio after three years have passed without the virus being detected in any of its countries.
- Nigeria is the last African country to be declared free from wild polio.
Where wild polio is still present?
Wild polio is still present in Pakistan and Afghanistan.
What is a vaccine-derived poliovirus?
It is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus.
- This means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an infected person. These viruses may cause illness, including paralysis.
How is it spread?
- Oral polio vaccine (OPV) contains an attenuated (weakened) vaccine-virus, activating an immune response in the body. When a child is immunized with OPV, the weakened vaccine-virus replicates in the intestine for a limited period, thereby developing immunity by building up antibodies.
- During this time, the vaccine-virus is also excreted. In areas of inadequate sanitation, this excreted vaccine-virus can spread in the immediate community (and this can offer protection to other children through ‘passive’ immunization), before eventually dying out.
InstaLinks:
Prelims Link:
- Which African country became the last African country to be declared free from wild polio?
- Countries where the Wild polio is still present.
- What is an attenuated (weakened) vaccine-virus?
- When a country is certified as free of wild polio?
- Composition and functions of the Africa Regional Certification Commission.
Mains Link:
Write a note on the vaccine-derived polio virus (VDPV) and the concerns around it.
Sources: the Hindu.
