The United States will keep in place all current COVID-19 travel restrictions for now due to concerns over the highly transmissible Delta variant.
A White House official told Reuters the decision came after a senior-level administration meeting late last week amid a rising number of U.S. coronavirus cases.
It's a signal that slowing vaccinations and rising cases are clouding the U.S. recovery. Adding to the mix is the new Delta variant.
Virologists and epidemiologies told Reuters the Delta variant is the fastest, fittest and most formidable version of the virus that causes COVID-19 the world has encountered.
Here's how former FDA commissioner Scott Gottlieb described it to CBS News:
"The physical characteristics of this virus has not changed. The reason it's more transmissible is that there's simply more of it; when people get infected they get more virus, higher viral levels, and they exude more virus so they're more contagious."
That means more infections and hospitalizations among the unvaccinated.
Experts said there is also mounting evidence the Delta variant can infect fully vaccinated people at a greater rate than previous versions, and concerns have been raised the vaccinated may even spread the virus.
"If you are vaccinated and you do develop an asymptomatic or a mildly-symptomatic infection, there probably is a higher chance that you can transmit this Delta virus than some of the old strains because there's just more of this virus. The viral levels are higher earlier in the course of the infection."
In the United States, which has experienced more COVID-19 cases and deaths than any other country, the Delta variant represents about 83% of new infections.
So far, unvaccinated people represent nearly 97% of severe cases.
The spreading Delta variant has led some municipalities to re-impose mask mandates and is upending expert assumptions about the path of the pandemic.
The travel announcement almost certainly dooms any bid by U.S. airlines and the U.S. tourism industry to salvage summer travel by Europeans and others impacted by the restrictions.
Airlines have heavily lobbied the White House for months to lift the travel curbs.
The United States currently bars most non-U.S. citizens coming from the United Kingdom, most EU nations, China, India, South Africa, Iran and Brazil.