China has spent over a year developing Pfizer-type Covid-19 vaccines that may even help it pivot from stringent "zero-Covid" restrictions, but a changed market and the Omicron variant have muddied prospects before efficacy data has even been published.

Still, China is unlikely to join the majority of countries in approving foreign-made vaccines based on messenger RNA (mRNA) technology before making its own, experts said, though a slowing vaccination drive at home and in some other nations and improved supply of approved vaccines have raised questions of viability.

"If they (China) use mRNA vaccines, they will produce them themselves rather than take it from outside. It is a matter of national pride and also vaccine diplomacy," said Jaya Dantas, professor of international health at the Curtin School of Population Health in Australia.

About 87 percent of China's 1.4 billion people are...