The Biden administration will stop shipping doses of Johnson & Johnson coronavirus vaccine to states next week, according to the Centers for Disease Control and Prevention, as a contamination incident two months ago at a Baltimore subcontractor continues to disrupt domestic production.

No new shipments for the one-shot Johnson & Johnson vaccine were included Thursday in the CDC’s weekly update on expected vaccine shipments. Shipments of the first and second doses of the two-shot Pfizer-BioNTech and Moderna vaccines will continue next week uninterrupted, according to the CDC shipment schedules.

The last federal allocation of Johnson & Johnson vaccine for states was for this week. That was a paltry 600,000 doses. Weekly allocations have been running at more than 10 million for Pfizer shots and nearly 8 million for Moderna.

The lack of new shipments of Johnson & Johnson’s vaccine may not have an immediate impact on individual states, which have some stockpiles, Marcus Plescia, chief medical officer for the Association of State and Territorial Health Officials, said Thursday. But it could cause concern if the shortage continues, he said.

The convenience of Johnson & Johnson’s single-shot vaccine, and the relative ease of storage and handling compared with the Pfizer and Moderna vaccines, has continued to bolster demand in many states, Plescia said.

“Everybody’s just hoping that this is just a little period that we’re going through and things will get back to where they were previously,” he said.

Some of the local reserves are left over from a 10-day pause in Johnson & Johnson vaccinations that the Biden administration called in April while it evaluated rare but dangerous blood clots associated with the vaccine. That pause was lifted April 23.

The Johnson & Johnson vaccine received an emergency-use authorization from the Food and Drug Administration in February. The company began delivering millions of shots in March, with a peak allocation to states of 5 million doses for the week beginning April 5.

All of its doses have been imported from a Johnson & Johnson manufacturing facility in the Netherlands. Emergent BioSolutions, a U.S. biodefense contractor that is manufacturing Johnson & Johnson’s vaccine in the United States, has been struck by problems and has not received FDA certification for domestic production.

Last month, the Biden administration stopped Johnson & Johnson vaccine production at Emergent and removed a production line for a coronavirus vaccine made by AstraZeneca after a cross-contamination crisis ruined 15 million Johnson & Johnson doses. The FDA issued a harsh inspection report that found unsanitary conditions and a lack of training and procedures to prevent contamination of vaccine batches. None of the contaminated vaccine made it into Johnson & Johnson’s supply chain.

Emergent said this week that it is working with the FDA and Johnson & Johnson to fix the problems, win certification and get production back on line.

“We have already started making improvements and we are fully committed to making the necessary short- and long-term enhancements to meet or exceed FDA’s standards,” the company said Tuesday. Johnson & Johnson, which has taken over production oversight at the Emergent plant, provided no details but said it is continuing to “partner closely” with the U.S. government on the facility.

Emergent officials are scheduled to appear at a hearing of the House select subcommittee on the coronavirus crisis on Wednesday.

Biden administration officials informed governors on a Tuesday call that no new Johnson & Johnson doses will be allocated next week, according to two people who participated and spoke on the condition of anonymity because the conversation was private.

During the previous week’s call, Jeff Zients, coordinator of the White House’s coronavirus task force, said more doses will be available once federal regulators clear use of Emergent’s Baltimore plant, according to a recording of the conversation obtained by The Washington Post.

While stressing that approval is up to the Food and Drug Administration, Zients said, “Everything we’re hearing is that it’s a matter of a week or two, and then there’s going to be a significant amount, because once it’s cleared, my understanding is that there’s a lot ready to go.”

Demand for the single-shot vaccine varies widely by state.

Even as officials in South Carolina planned to cut back orders of the Pfizer and Moderna vaccines, they said they would continue to claim as much of the Johnson & Johnson vaccine as is made available to them because it is easier to store.

“The reason we’re taking all of our [Johnson & Johnson vaccine] is because we’ve got different plans for the [Johnson & Johnson] vaccine, from mobile clinics,” Jane Kelly, assistant state epidemiologist, said last week. “It can sit for six months in the fridge, so it’s easy to store it.”

Connecticut, meanwhile, has stopped ordering the Johnson & Johnson vaccine because the state has not been able to use up a stockpile of that product, said Josh Geballe, the state’s chief operating officer. When use of the vaccine was paused nationwide last month, Connecticut had about 125,000 doses on hand, he said.

Since the pause was lifted, the state has been able to administer only about 6,000 doses. “We have seen some demand for J&J, but well below the levels we had seen before the pause,” Geballe said.