The head of the World Health Organization earlier this year called for an urgent push to hit that target by the end of September. But more than 55 countries remain short of the goal, illustrating the problems that the Covax distribution program has faced in its bid to roll out vaccines to every corner of the planet.

Covax earlier this month cut its 2021 supply forecast, hobbled by production delays, export bans and moves by wealthy countries to protect their own people first. Partners in the program have called on countries that already have enough doses to accelerate donations and give up their place in the queue, and urged companies to be more transparent about their supply arrangements.

“Manufacturers are making a choice not to ship to Covax, and high-income countries are making a choice not to get sufficient doses into these places fast enough,” Bruce Aylward, a senior adviser to the WHO, said in an interview. “There’s no way to sugarcoat it.”