US President Donald Trump speaks during a ceremony presenting the Presidential Medal of Freedom to wrestler Dan Gable in the Oval Office of the White House in Washington, DC on December 7, 2020.Saul Loeb | AFP | Getty ImagesPresident Donald Trump is expected to sign an executive order on Tuesday designed to ensure that U.S. efforts to assist other countries in vaccinating their populations against Covid-19 take on a lower priority than domestic inoculations, a senior administration official told NBC News.The executive order will be in line with the president’s “America First” foreign policy, the official said. The plans for the executive order were earlier reported by Fox News. The official said that the order will contain a framework for getting vaccines to foreign countries “once we’ve ensured we’ve met the needs of the American people.”CNBC has not reviewed the proposed text of the executive order, which could prove to be largely symbolic.The official said that the timeline for providing foreign assistance will be shaped by supply and demand, but is anticipated to begin in the second quarter. President-elect Joe Biden will take office on Jan. 20 and is likely to shape his own policy for obtaining and distributing Covid-19 vaccines, possibly limiting the impact of Trump’s order.Also on Tuesday, the White House is set to host a Covid-19 summit featuring vaccine manufacturers, drug distributors and government officials, the medical news outlet STAT reported.Trump has largely ignored the growing coronavirus crisis in recent weeks despite a surge in infections and a mounting death toll that has surpassed 2,000 fatalities per day, instead focusing on legal efforts to overturn the results November’s presidential election.Nonetheless, the signing will come at a particularly critical phase of vaccine development.Trump will sign the order just days before the Food and Drug Administration meets, on Thursday, to review a promising vaccine made by Pfizer and German drugmaker BioNTech.That vaccine may be authorized for use as soon as the end of this week. The FDA will meet to discuss another candidate made by Moderna on Dec. 17.While some particularly vulnerable Americans could be vaccinated shortly after the vaccines are approved, officials are warning that it will take months for everyone who wants a vaccine to receive one.Health and Human Services Secretary Alex Azar predicted on Sunday that vaccines are not likely to be available to everyone who requests one until the second quarter.The White House and the HHS did not immediately provide details of the executive order. Pfizer and BioNTech did not return emails seeking comment.Subscribe to CNBC Pro for the TV livestream, deep insights and analysis on how to invest during the next presidential term.