President Joe Biden’s attempts to limit the spread of the new Omicron Covid-19 variant begin on Monday with new US restrictions on travel from South Africa and seven other countries taking effect, as his administration seeks to assure Americans that they are moving swiftly to try to contain the threat.

Much is still unknown about the transmissibility of the new variant and how effective vaccines will be in protecting Americans against it, but the administration is attempting to strike a more proactive stance than they did this summer when they appeared to be caught flat-footed by the highly contagious Delta variant, which now accounts for the vast majority of cases in the United States — and blunted Biden’s efforts to speed the country back to normalcy in the first year of his term.

In his haste to turn the page from the pandemic, Biden predicted a “summer of freedom” at the same time the Delta variant was taking hold across the United States and went so far as to proclaim that America was “closer than ever to declaring our independence from a deadly virus” at a July Fourth event. With those missteps in mind, Biden spent Sunday evening huddling with advisers, and plans to speak Monday on the situation. He moved rapidly to announce the new travel restrictions Friday after the World Health Organization labeled Omicron a “variant of concern,” a signal that the White House was taking the new variant first identified by scientists in South Africa seriously.

The travel bans alone, however, may offer little comfort to Americans given the widespread debate among public health officials about their effectiveness. Anxiety over this new Covid threat is particularly high after a week of heavy travel and a Thanksgiving holiday that had offered a fleeting sense that the nation was returning to normalcy. On Wednesday before Thanksgiving, Americans set a new pandemic-era air travel record with the Transportation Security Administration reporting that it screened 2.3 million passengers at airports on that day alone.