COVID-19 vaccine shipments have ground to “a near halt” in Africa while virus cases have spiked 20% over the last two weeks, the World Health Organization said Thursday, a bleak scenario for the continent on both those critical fronts.

South Africa alone saw a more than 60% rise in new cases last week as the country with the highest coronavirus caseload in Africa continued to face delays in its effort to roll out the single-dose Johnson & Johnson vaccine.

More than 1 million J&J doses that should have already been put to use remain on hold at a pharmaceuticals plant in South Africa because of contamination concerns at a U.S. factory. The head of the Africa CDC said he expects an update in the coming days from U.S. federal regulators on those and other doses of J&J, which he called an essential vaccine for Africa because it’s a one-dose shot and doesn’t need the ultra-cold storage facilities required by others.