The White House and the Centers for Disease Control and Prevention are reportedly at odds over a plan for booster shots for COVID-19 that could delay its rollout.

In a report Monday by Politico, federal health officials at the Food and Drug Administration and White House accused the CDC of withholding key data needed to develop the booster plan.

Sources told Politico that meetings of the White House’s COVID-19 task force have been beset by disagreements between officials on all sides about the plan. One episode in particular that drew the ire of White House and FDA officials was a perceived public rebuke of the plan by CDC Director Dr. Rochelle Walensky. She had previously joined an Aug. 18 statement on booster shots, but shortly after appeared to backtrack from a nationwide plan by advocating initial shots for particularly vulnerable groups first.

Previously, FDA and CDC officials expressed frustration with the Biden administration for publicly pushing the Sept. 20 start date for a booster vaccination campaign because it went ahead of the available science to support it. Walensky warned that the booster plan for Sept. 20 was too ambitious and would undermine President Joe Biden’s public statements that his administration would be following the science in its public health decisions.

Discussions about booster shots as a means to fight the COVID-19 Delta variant have picked up in recent weeks.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, has endorsed boosters, citing medical studies from Israel where the shots were being used. However, the health officials have warned that not enough data is available from vaccine providers Moderna and Johnson & Johnson on booster shots, which would limit the number of shots potentially available to only those from Pfizer-BioNTech.

Disagreements between public health officials and the White House are not new. Former President Donald Trump frequently clashed with health authorities who undermined his public statements, weakening morale at the CDC and other agencies tasked with combating the pandemic.

The Biden administration has insisted on following a science-based approach, but it has experienced its own difficulties. In August, two senior FDA officials left the administration over disagreements with the CDC and frustration with the Biden team’s plan to push the booster announcement for Sept. 20. One official told CNN that they felt the White House was overstepping the FDA with this decision.