The World Health Organization on Wednesday declared the COVID-19 outbreak a pandemic, now that there are instances of human-to-human transmission of the virus on several continents.

At least eight countries have reported 1,000 or more cases of COVID-19 among their residents, including the U.S., France and Germany.

WHO officials said the number of cases outside China has increased tenfold and the number of countries affected has tripled.

“Pandemic is not a word to use lightly or carelessly,” WHO Director-General Tedros Adhanom Ghebreyesus told reporters. “It is a word that, if misused, can cause unreasonable fear, or unjustified acceptance that the fight is over, leading to unnecessary suffering and death.”

The U.S. case count is now 1,110, with 30 deaths in California, Florida, New Jersey, South Dakota and Washington state, according to the most recent data from the Johns Hopkins Whiting School of Engineering’s Centers for Systems Science and Engineering.

Growing concern about the potential impact of the outbreak in America has prompted further cancellations of major events and even more sizable work-from-home policies.

Coachella, the annual music festival in the Sonoran Desert in California, has been postponed until October. A pair of payments companies — Fiserv Inc. FISV, -0.28% and Square Inc. SQ, -0.43% — are either postponing investor days or moving them to a webcast format. Endo 2020, a medical meeting for endocrinologists, has been canceled, as has a large cardiologists gathering in Chicago, one of numerous trade shows in that city to postpone events. The Yonkers Raceway, a horse track, has been closed after an employee in the racing office died after testing positive for COVID-19, according to MGM Resorts International MGM, -2.22% , which last year acquired the adjacent Empire City Casino. Google and YouTube parent Alphabet Inc. GOOGL, -2.41% told all North American employees to work from home.

In Europe, where outbreaks in France, Germany, Italy and Spain have worsened in recent days, similar initiatives are being taken.

Spain now has 2,182 cases and has recorded 49 deaths; Germany, 1,908 cases and three deaths. Italy, which is under a countrywide quarantine, has had 12,462 cases and 827 deaths, and France has 1,784 cases and 33 deaths. (The counts for France haven't yet been updated today.)

Banco Santander SAN, -3.78% , Spain’s largest bank, is encouraging shareholders to vote before its annual meeting and attend remotely over coronavirus worries, while Spain’s health authorities on Wednesday calculated that the country could overcome its outbreak within two months, though experts remain doubtful. “In the worst case, that could be four or five months,” Spain’s director of the Center for Coordination of Health, Fernando Simón, said in a briefing, according to Spanish daily newspaper El País.

In Madrid, students of all ages stayed home from school on Wednesday in what will initially be a 15-day period as the government tries to get a grip on soaring infections, half of which are in the region. The city’s parks were full of grandparents — a group at high risk of contracting the virus — looking after grandchildren while parents were at work.

Tuesday evening, terraces that would normally be packed had free tables, while some bar owners milled at the doorways with no one inside. At a local grocery store, Mercadona, the shelves had been stripped bare of fresh meat and chicken, and most fruit. There were no fresh or frozen vegetables, beans or lentils, sandwich meat and pasta were running low, and just a few packages of toilet paper were on the shelves.

Worldwide, there are now 124,578 cases of COVID-19, and at least 4,584 deaths; more than 66,000 people have recovered since the novel coronavirus was first detected in December in Wuhan, China. The number of newly identified cases in South Korea rose overnight, to 7,755 cases and 61 deaths. Iran now has 9,000 cases and 354 deaths.

This follows a day in which multiple airlines said they would cut capacity and rein in costs due to a drop-off in travel bookings due to coronavirus worries and travel restrictions.

United Airlines Holdings Inc. UAL, -3.61% President Scott Kirby, who is forgoing a salary until July as a result of the outbreak, said Tuesday at an investor conference that the company’s net bookings to Asia and Europe are down 100%; the company’s “dire scenario planning assumption” is that revenue will be down 70% in April and May. In comparison, demand was down 40% for the two months following 9/11. Kirby said he expects demand to recover within 18 months.

“Let me be blunt,” he said, “speaking for United, hope is not a strategy. Our strategy is to act quickly, raise liquidity, cut operating expenses, cut capital expenditures and reduce capacity to position ourselves to bounce back when the crisis ends and demand returns.”

The Federal Aviation Administration said Wednesday it is temporarily waiving slot-use minimum requirements for airlines as demand for travel drops in the U.S.

Here’s what companies are saying about the impact of COVID-19:

• 3M Co. MMM, -1.64% said demand for respirators is currently outpacing supply, and that increased demand for respirators during the H1N1 influenza outbreak in 2009 generated $250 million in revenue for the company. “That’s maybe the best frame to think about it for coronavirus at this point,” CEO Mike Roman said at an investor conference.

• Urban Outfitters Inc.’s URBN, -3.14% store traffic and sales fell over the past week in cities including Milan and Seattle where the coronavirus is having a heavy impact. Other cities have been affected as well. The company, which also operates Anthropologie and Free People, said it can’t forecast how the company will be impacted in the first quarter because of the uncertainty around the outbreak.

• Xenia Hotels & Resorts Inc. XHR, -0.94% withdrew the 2020 guidance provided in late February, citing increased uncertainty regarding the financial impact resulting from the coronavirus outbreak. The real-estate investment trust that invests in luxury hotels said group cancellations have increased to $15 million of revenue since Feb. 24, while transient cancellations have increased significantly.

• Dow Inc. DOW, -1.17% expects the coronavirus to shave about $400 million off first-quarter sales, after business in China saw a 20% to 30% dip in sales. CFO Howard Ungerleider told a JPMorgan industrials conference that the chemicals company expects some additional sales impact, but that it is difficult to quantify for now. “However, if I had to size the total impact of COVID on our first quarter based on what I know today, both the impact in China and the knock-on impacts around the world, I would arrange the total impact to the Dow in the first quarter in the $200 million range on Ebitda,” the executive told attendees, according to a FactSet transcript.

Additional reporting by Barbara Kollmeyer. Ciara Linnane, Tomi Kilgore and Tonya Garcia contributed.

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