New restrictions from the Omicron variant are causing more barriers for international travel, which directly impacts students studying abroad.

As colleges and universities closed at the start of the pandemic, most airlines cut capacity by up to 90% and over 80 countries had suspended flights in and out. This left international students stranded with little to no flight options to return home.

As the Omicron variant begins to spread, students fear the same challenges will resurface.

The U.S., for example, is home to the largest international student population and its travel-related decisions impact over one million students.

Most recently, it began requiring air travelers flying from abroad to show airlines proof of a negative COVID test result that was taken within one day of departure before being allowed to board.

The U.S. has also banned entry from visitors from South Africa, Lesotho, Eswatini, Botswana, Namibia, Malawi, Mozambique and Zimbabwe.

Meanwhile, the U.K. requires vaccinated visitors to book a post-arrival test on their second day in the U.K. and self-quarantine until receiving a negative result. Those unvaccinated must get a pre-arrival test, self-quarantine for the first 10 days and get two negative tests while in quarantine.

Other countries are also requiring quarantines, testing and additional COVID safety protocols.

With this, many students had to reconsider their travel plans, which meant they could potentially spend another holiday season away from home.

“We are concerned,” Gerri Taylor, co-chair of the American College Health Association COVID-19 task force, told the Washington Post. “So many questions are coming up because of this, for sure.”

In the U.S., international students study through a non-immigrant temporary visa. They are typically foreign nationals who are temporarily in the U.S. under a F1, M1 or J1 Visa.

It is common for these students to return home during school holidays but COVID has often left them stranded either away from their home country or unable to return to the U.S. to resume their studies.

The struggles COVID-19 brought have also had a direct impact on how many choose to enroll in U.S. colleges and universities.

In 2020, U.S. schools saw a 72% decrease in new international student enrollment compared to 2019, according to a report from the Immigration and Customs Enforcement.

Most notably, new international student enrollment dramatically decreased in August and September, months that usually see the largest numbers of enrollment. In August 2020, there was a 91% decrease in new F-1 international student enrollment and a 72% decrease in new M-1 students, the report found.

Many schools are anticipating that more international students will remain on campus over the break, given concerns about prevalence of Omicron in other countries and abrupt travel restrictions, the Post noted.

Most recently, the World Health Organization announced that travel restrictions imposed by some countries may buy time to fight the new COVID-19 variant Omicron.

Speaking at a virtual news conference from the Philippines, WHO officials added that measures used to fight the Delta variant should work for fighting the Omicron variant. Those measures include pushing for higher vaccination rates, wearing face masks, social distancing, contact tracing and other measures.