Polio now only in Pakistan, Afghanistan

China's expertise may prove crucial to global effort to eradicate the virus

China's experience in eradicating polio and fast, effective stamping out of isolated clusters in recent years may be of value to the rest of the world as the global mission to end the infectious disease stands at a critical juncture, health experts said recently.

Polio is a potentially deadly disease that once used to paralyze tens of thousands of infants and children every year. But thanks to coordinated global vaccination efforts, the annual number of polio cases fell from over 300,000 about three decades ago to just 22 in 2022, according to Margaret Chan Fung Fu-chun, former director-general of the World Health Organization.

However, two countries — Pakistan and Afghanistan — still experience cases of polio.

"As long as there is one case, 450 million children worldwide will still need to be vaccinated each year. Global polio eradication requires more medical resources as we enter the last mile," Chan, who is also chairperson of the Global Health Forum of the Boao Forum for Asia, said in Beijing on April 22.

China reported its last domestic case of polio in 1994 and was certified polio-free in 2000. "However, a high risk persists due to continued presence of wild strains of polio in Pakistan and Afghanistan, two neighboring countries to the west of China," Chan said.

"Global polio eradication requires solidarity and cooperation," she continued, adding that China's medical assistance and innovative technology are pivotal to achieving the goal.

Aidan O'Leary, Director for Polio Eradication at the WHO, said that China's successful eradication of endemic poliovirus in the 1990s demonstrates the feasibility of wiping the virus out in densely populated areas, adding that when an imported case from Pakistan was recorded in the Xinjiang Uygur autonomous region in 2011, triggering a local cluster, the swift and comprehensive response of the Chinese government stopped the outbreak in just three months.

"Eradication strategies, many of which were trailblazed in China, are actively being applied in the last two remaining endemic areas to great success," O'Leary said.

"Right now, we have a clear window of opportunity that we must use before it closes to stop transmission in these remaining endemic reservoirs, including in areas bordering other countries," he said, adding that China's pioneering development of Sabin strain-based inactivated polio vaccines will play a critical role in the post-eradication era.

Shen Hongbing, head of the Chinese Center for Disease Control and Prevention, said that launching mass vaccination, immunity boosting campaigns and creating a surveillance system have enabled China to wipe out the disease.

"In the meantime, we are also participating in global eradication efforts, dispatching experts in 2011 and 2012 to Nigeria and Pakistan to provide on-site technical guidance," he said. "We will continue to step up global cooperation to finish the last mile to eradication."

Yu Zirong, vice-president of Chinese Academy of International Trade and Economic Cooperation, suggested prioritizing polio eradication in the country's international cooperation projects and devising comprehensive aid projects in support of this goal.

"China has accumulated a great deal of experience in delivering vaccines, strengthening immunity, adjusting inoculation procedures and establishing science-based monitoring systems, which can be shared with the international community," he said.

In addition, Yu said that domestic polio vaccines and cold-chain storage and transportation facilities have become global public goods. "China could donate vaccines, supply cold-chain equipment and train local vaccination staff," he said.

More domestically developed polio vaccines are in the pipeline. Zhang Yuntao, vice-president of the China National Biotech Group, said that several multivalent polio vaccines are expected to start appearing in the market in 2024. The company also plans to apply for authorization from the WHO to facilitate global distribution.