New clusters of the novel coronavirus are expanding in the United States and Europe as Italy replaces China as the new epicenter of a worldwide outbreak.

For most people, the new coronavirus causes only mild or moderate symptoms, such as fever and cough. For some, especially older adults and people with existing health problems, it can cause more severe illness, including pneumonia.

These are some of the latest developments on Wednesday:

BEIJING ORDERS QUARANTINE FOR ALL FOREIGN ARRIVALS

Beijing's city government ordered all passengers arriving in the city from overseas, regardless of their points of departure, to undergo a 14-day quarantine. The move was part of stepped-up measures to prevent the new virus first detected in China from re-entering the country following its spread across the world. The number of cases in China has been falling, with just 24 new confirmed cases reported Wednesday but five of those had arrived from Italy and one from the United States.

AN EXPANSION OF SCHOOL CLOSURES

Poland and Ukraine have joined the countries deciding to close all schools, preschools and universities because of the coronavirus, even though the two eastern European nations have small numbers of confirmed cases. The nation of Georgia has 23 confirmed cases and similarly extended spring break for students until April 1. It comes as a growing number of U.S. colleges and universities, including Harvard and Yale, are extending spring breaks and moving classes online, as the U.S. registered more than 1,000 cases.

NEW CLUSTER EMERGES IN SOUTH KOREA

While cases have been waning in South Korea, a new cluster in Seoul raised alarms. The cluster was connected to a call center in one of the busiest areas of the capital. So far, 93 people have tested positive among the call center’s employees and their families, but the number could grow as hundreds more undergo testing. South Korea’s caseload of 7,755 infections and 54 deaths is the fourth highest in the world after China, Italy and Iran.

A STRONG WARNING FROM GERMANY'S LEADER

German Chancellor Angela Merkel is citing expert estimates that up to 60% to 70% of the population could be infected by the new coronavirus as she insists on the necessity of measures to slow its spread. She said the reason is because people do not yet have immunity to the virus and there are so far neither vaccines nor therapies to fight it. With some 1,300 infections and two deaths, Germany's government has recommended the cancellation of all events with more than 1,000 people, among other measures. Merkel said such measures "are giving us time” and are invaluable.

GRETA THUNBERG SAYS KEEP PROTESTING, BUT DIGITALLY

Climate activist Greta Thunberg is urging people to protest digitally rather than in person because of the coronavirus outbreak. On Twitter, the Swedish teenager told followers to “keep your numbers low but your spirits high." She said the challenge was to find new ways to create public awareness and advocate for change that don’t involve creating big crowds. Ahead of upcoming climate change rallies, Thunberg said people could post photos of themselves with their signs and listed some hashtags they could use.

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