One quote from this article:
“For some, it has gone back to normal, and because of this, it will be two to three years before things are back to normal for the cautious, at least in the U.S.”
After all, if the world can only produce 2 billion doses of vaccine a year it'll be a few years before international travel is back to normal.
Some of the people surveyed may even have responded before vaccine clinical trial results came out...
Edit: “According to Census and State Department data, 21.4 million passports were issued in 2016, which is the most ever. That means 42 percent of Americans hold a passport, a growth of 15 percent since 2007. In 1990, only four percent of Americans had one.”