Entry requirements differ by country, as do mask measures, capacity limits, curfews and proof of vaccination. Italy, for one, recently waived the 10-day quarantine requirement for Americans who have been vaccinated, can present a negative test result or prove that they have recovered from the virus. Previously, only travelers arriving on coronavirus-tested flights were exempt. Starting Aug. 6, anyone over the age of 12 must present a “digital green certificate” to access certain businesses and services, such as restaurants, bars, gelato and pastry shops with indoor tables, museums and sporting events. In France, the government passed a similar law that applies to all adults and will extend to those ages 12 and older on Sept. 30. Earlier this month, Malta announced that it would not accept CDC vaccination cards, but promptly reversed course. However, to enter the country, Americans must upload their medical information and documents on the VeriFLY app. England will lift the quarantine requirement for vaccinated Americans starting Aug. 2, though the testing rule remains in place. Meanwhile, the State Department and CDC have increased their warnings on several European destinations, including the United Kingdom, Portugal, Cyprus and Spain, and are advising travelers to avoid these countries.