A Chinese pharmaceutical maker is in talks with several countries to get emergency approval to use an experimental Covid-19 vaccine, developed with the Chinese military, before the completion of large-scale safety and effectiveness trials, according to a senior executive at the company.

Early distribution by CanSino Biologics Inc. would give the company a head start over rivals by making its vaccine the first to go into public use internationally outside of clinical trials, although initial doses would likely be directed at health-care workers and others deemed essential, such as military personnel and police…

Pierre Morgon, senior vice president for international business at CanSino, said getting the vaccine out to millions of people now, before its clinical trials are complete, would broaden the base of knowledge about the drug’s safety and effectiveness. By comparison, final-stage experimental trials typically involve several thousand participants. Such early distribution would require the countries to authorize the drug for emergency usage.

“It helps to build the safety database and certainly build the confidence in the fact that the vaccine is safe. If, in the meantime, if it is demonstrated as being effective in the Phase 3 trials, then it might be an accelerator for future contracts for vaccine supply,” said Mr. Morgon.