Johnson & Johnson will ship relatively few COVID-19 shots around the United States until it receives regulatory clearance for a large vaccine plant in Baltimore that has struggled to meet quality control standards, a top White House Health official said on a Friday press conference.

A CNN analysis of data from the Centers for Disease Control and Prevention indicated the drop in shipments to be 84%.

J&J is working closely with the U.S. Food and Drug Administration to resolve the issues holding up authorization, said Jeff Zients, the White House’s COVID-19 response coordinator.

Once J&J receives authorization for its Baltimore facility, it expects to start shipping 8 million doses per week towards the end of April, Zients said, adding J&J remains on track to deliver around 100 million shots by the end of May.

J&J’s shot was authorized for use in the United States in late February but has faced production challenges in its Baltimore manufacturing facility, which is owned by Emergent BioSolutions Inc.

J&J has taken over operations of the facility after Emergent ruined 15 million J&J doses in recent weeks due to manufacturing errors.

Cases of COVID-19 have been rising in the United States, with the current seven-day average hovering around 64,000 new cases per day, U.S. Centers for Disease Control and Prevention director Rochelle Walensky said on the call.

The U.S. government plans to continue allocating shots based on population rather than surging doses to the areas that have been hardest hit by the virus, Zients said.

“We will be offering to states with significant increases in cases a set of additional tools to help them to stem the spread,” including a surge of federal personnel to help states administer their existing dose supplies, Zients said.

“Today, millions of doses have been distributed but have not yet been administered as shots in arms,” Zients added.

The United States remains on track to give out 200 million doses by President Joe Biden’s 100th day in office, Zients said. It has so far dosed 112 million people and fully vaccinated 66 million people, he said.

Top U.S. infectious disease expert Dr. Anthony Fauci said he has no concerns that COVID-19 cases reported in vaccinated people indicate any change in the effectiveness of authorized shots.