The data from the U.A.E. may not be a final indicator of the vaccine’s overall efficacy. Sinopharm has been running trials in 10 countries, data from which has not yet been released.

It is unclear whether the U.A.E. would start a mass vaccination program — the government had already approved the vaccine for emergency use in September for frontline workers at risk of contracting Covid-19. Separately, Morocco said it is preparing to vaccinate 80 percent of its adults, relying initially on a Sinopharm vaccine, the Associated Press reported.

Because the coronavirus has largely been stamped out in China, Chinese vaccine makers had to launch Phase 3 trials in places with active outbreaks to fully conclude whether their vaccines are effective. Sinopharm, which has two vaccines in late-stage testing, is also conducting trials in Bahrain, Jordan, Peru and Argentina and elsewhere, involving more than 60,000 volunteers.