Airlines are reducing more service and offering fee waivers to travelers headed to Asia and other parts of the world where coronavirus infections are growing.

On Friday, United Airlines announced it would cancel some flights to Japan, Singapore and Seoul. The airline also said it would extend cancellations of flights between the United States and China through the end of April. American and Delta have already suspended China service though the end of April.

“We will stay in close contact with the CDC and other health organizations as we continue to evaluate our schedule,” United said in a statement.

The announcement came as the World Health Organization raised its assessment of the coronavirus to “very high,” citing the risk of spread and impact.

Delta Air Lines this week also suspended service between its hub at Minneapolis-St. Paul and South Korea from Feb. 29 through the end of April. It is reducing flights between South Korea and Atlanta, Detroit and Seattle through April 30 and is delaying the launch of service between Seoul’s Incheon International Airport and Manila. Those flights, set to launch March 29, will now begin on May 1, the airline said.

Earlier this week, Hawaiian Airlines suspended nonstop service between Honolulu’s Daniel K. Inouye International and Seoul’s Incheon airports starting March 2 and through the end of April. The airline is also offering to waive change fees for travels between Honolulu and South Korea through May 1.

United, American and Delta also have extended travel waivers for flights to and from northern Italy, which has seen a significant uptick in the number of infections.

The moves come amid concerns about the virus, which has continued to spread worldwide. The covid-19 disease, once centered in China, has spread worldwide, with the number of new infections in other countries outpacing the number in China. South Korea, which said the number of people infected is now more than 2,300, has been among the hardest hit, but Italy is also is working to contain an outbreak in the northern region of the country. On Friday, France and Germany reported increases in the number of infections.

The travel industry — from airlines to hotels to cruise ships — has been hit hard.

A survey released this week by the Global Business Travel Association estimated the virus could potentially cost the industry $46.6 billion per month. That number equates to $559.7 billion annually.

A snap poll of association members this week found the virus has had a major impact on business travel to Asia, with 95 percent of companies reporting cancellations or suspensions of most or all business travel to China. In January, all three major U.S. carriers announced they were halting all flights to China and Hong Kong. About one-fourth of those surveyed said they’ve also canceled or suspended travel to Europe.

“It is clear that the coronavirus is having a significant — and potentially very costly — effect on our members, their companies and on the overall business travel industry,” said Scott Solombrino. GBTA’s chief operating officer. “It is fundamentally affecting the way many companies are now doing business. If this turns into a global pandemic, the industry may well lose billions of dollars — an impact that will have negative ramifications for the entire global economy.”