China Under Pressure to Reveal Vaccine Data After Pfizer Success

Western politicians have faulted China for initial delays in providing information as the coronavirus spread around the world. Now as Beijing develops a vaccine, the need for transparency is proving essential to win back trust.

American drugmaker Pfizer Inc. and German biotechnology firm BioNTech SE announced this week that its vaccine appears more than 90% effective in stopping Covid-19 infections. The preliminary finding spurred a global stock rally and put the companies at the head of the pack in the race for the vaccine.

At around the same time, China saw the final-stage trial of one of its top vaccine ...