It is, but the rub with regards to international travel is that the places that are the most likely destinations abroad that Americans typically want to go to are either UK, or a country in the EU zone (which only has 88% 2nd dose coverage) -- as noted Russia has really good coverage, but it's not exactly a "destination hotspot" for obvious reasons.
...and addressing the issue in a more comprehensive matter isn't "helped", shall we say, by the fact that they only seem to get brought up within the context of news stories that afford people a convenient political jabs at their opponents...hence the posts in here that are taking direct shots at South Carolina and a creationism museum in Kentucky.
Meanwhile, in reality, despite efforts to portray it as such, it's not a "red state problem"
Oregon, New Jersey, Washington State, Minnesota, Colorado, and New Hampshire have the same poor rates of coverage (a few are even worse than South Carolina in that regard)
Rates have been declining across the country, with all kindergartner coverage for each of the vaccines having dropped since 2021.
www.newsweek.com
And I think that could be one of the reasons why it's not taken as seriously as it should be, because when it only seems to get brought up in the context of stories where it's clearly a "political swipe", it conveys the notion of "well, clearly it's not something they're actually concerned about, it was just a cheap way of bashing their political rivals".
As you can see by the interactive map (lets you hover over each state and see their rate of MMR coverage), the implied tone of "those darn MAGA people are risking another measles epidemic" isn't remotely accurate.
If they want to say "A ha! see, look...it's those red hat people in Kentucky and SC following Trump and RFK and it made them reject science", then I'd like to hear what their explanation is for New Jersey, Colorado, Minnesota, and Oregon.