Although rare, China is working to make polio a thing of the past.

The country has set a goal to introduce the inactivated polio vaccine, which does not pose a risk of paralysis, into its routine immunization program in two years. Officials say an application has already been filed with the State Food and Drug Administration for mass production and use of the first domestically made IPV.

"The oral vaccine has helped China eliminate polio, and now we're preparing to introduce IPV, which is in line with the international standard and can better protect against polio infection," said Shen Qi, deputy director of the National Institutes for Food and Drug Control's Institute for Biological Product Control.

Polio, or poliomyelitis, is a virus that infects the brain and spinal cord, mostly in children under age 5. One in every 200 cases leads to paralysis, usually of the legs.

The World Health Organization is requesting countries that use only the oral vaccine to introduce at least one dose of the inactivated vaccine before October 2015.

Polio immunization usually includes four doses administered at different times.

IPV, which is injected rather than swallowed, can help prevent vaccine-associated paralytic polio from subsequent doses of oral polio vaccination when given in a combined schedule, according to Lance Rodewald, team leader of the WHO China Office Expanded Program on Immunization.

Since its launch at the 1988 World Health Assembly, the Global Polio Eradication Initiative has reduced the global incidence of polio by more than 99 percent. The number of countries with endemic polio has been cut from 125 to three. The WHO recognized China's polio free status in 2000.

In May, the assembly approved the Polio Endgame Strategic Plan, which requests global withdrawal of the oral vaccine in a coordinated manner.

Worldwide, most of the vaccine in use is oral, yet more than 60 countries and regions have introduced IPV. Some only use IPV, while some use both.

"Eventually all use of OPV (the oral vaccine) will be ended in China and the world," Rodewald said. "However, there will be a few years in which both IPV and OPV are likely to be used together."

It is critical, he said, that polio vaccination coverage remains high in China, because it shares borders with Pakistan and Afghanistan, where polio remains endemic.

Che Yanchun, director of science and technology at the Chinese Academy of Medical Sciences' Institute of Medical Biology, said in February it applied for a license to produce and use it after clinical trials.

"To eliminate polio thoroughly, we can't depend solely on foreign products. We must have a homegrown IPV," she said.

However, Rodewald said China faces challenges in introducing an IPV.

The supply will need to be sufficient for all children to receive at least one dose, he said, while the increase in injections will put pressure on public health workers.

Shen at the Institute for Biological Product Control also said there is a cost implication. According to her, one dose of the oral vaccine costs less than 1 yuan, "but IPV is far more expensive."