TEMPO.CO, New Delhi - The World Health Organization (WHO) has certified Indonesia, along with 11 other Southeast Asian countries, as polio free. The certificate was handed over in WHO office in New Delhi, India, Thursday.

"This is very significant because before, this region was certified polio-free, we had half the world's population polio free.

"With the Southeast Asia region being added, we now have 80% of the population polio free," said Dr Poonam Khetrapal Singh, WHO Southeast Asia regional director as quoted by BBC.

"This was a problem the region was struggling with for a long time, but now finally, we are polio free," Dr Poonam added. The disease is still endemic in Afghanistan, Nigeria and Pakistan.

The Director General of Health Ministry’s Environment and Disease Control, Tjandra Yoga Aditama said Indonesia will continue to improve the scope of polio immunization include changing the vaccine toward B-OPV (Bivalent Oral Polio Vaccine) and IPV (Inactivated Polio Vaccine).

However, WHO admits there were still major challenges to overcome if the world wants to fully eradicate polio by 2018. Polio also reappears in Syria region after the conflicts continue to hit the country.

Polio mainly affects children under five years old. The virus is transmitted through contaminated food and water, and multiplies in the intestine. It can then invade the nervous system, causing paralysis in one in every 200 infections.

BBC | NATALIA SANTI