What Americans need to know about finding a coronavirus test abroad Natalie Compton A doctor conducts a rapid antigen test in Mexico City. On Jan. 26, a Biden administration executive order went into effect requiring a negative coronavirus test result before entry into the United States, creating a significant change in how Americans travel during the pandemic. Travelers, including residents returned home to the United States, must show their airline a negative test result taken within three days of departure or show proof they’ve recovered from covid-19 in the past 90 days. Even those who have been vaccinated must provide a negative test result.