Travelers almost always have to be fully vaccinated — which is commonly defined as two weeks following the last required dose. However, several places allow travel the same day as a second shot. All this is to say: Travelers should read the fine print before booking a trip abroad, which includes understanding Covid-19 protocols that may be stricter than what’s required at home. Stefan Cristian Cioata | Moment | Getty Images The U.S. CDC may have eased mask rules for fully vaccinated Americans who are outside, but other places, such as Greece, have not. A study by the rental search engine HomeToGo showed 54% of U.S. travelers plan on taking a trip within the first two months of getting vaccinated. Yet, the rise of Covid-19 variants is complicating matters.