President Donald Trump’s administration is slated to lay out its approach to Covid vaccination at an event Tuesday that could spell major changes in what is required to get regulatory approval for immunizations.

Novavax originally showed its vaccine was safe and effective in a 30,000-person clinical trial. The FDA had been on track to grant Novavax full approval – without restrictions -- by its April 1 target date, according to two people with direct knowledge of the situation who spoke on condition of anonymity to discuss confidential agency matters.

The vaccine will only be available to those at high risk from COVID—excluding those who may need it to protect a relative or friend.