What happens if the coronavirus outbreak becomes a pandemic?

LOS ANGELES – Roughly 50 million people are under quarantine in China. Thousands of travelers are being screened at airports every day. Armies of disease detectives are knocking on doors around the world in hopes of halting the new coronavirus in its tracks.

Despite all the colossal efforts to contain the virus, scientists are quietly preparing for a grim – and increasingly likely – outcome: A full-blown global pandemic.

Since the novel virus was isolated in December in the Chinese megacity of Wuhan, the pathogen has reached four continents and infected more than 24,000 people. At least 493 of them have died as a result. With the outbreak continuing to expand, authorities acknowledge that efforts will soon shift from trying to squelch the coronavirus to learning to live with it.

“We’re proceeding as if things go really sour on us in the coming weeks and months,” said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases at the National Institutes of Health. “We’re working for the worst-case scenario.”

The World Health Organization raised the stakes last week by declaring a public health emergency of international concern. The Trump administration responded by proclaiming a public health emergency in the United States, restricting incoming flights from China and ordering the country’s first mandatory quarantine in more than 50 years. Yet the outbreak shows no signs of slowing down. Infectious disease experts at Imperial College London have calculated that each person infected with the virus early in the outbreak spread it to 2.6 others, on average. For the sake of comparison, in the early days of the 1918 Spanish flu outbreak, each person who became sick is thought to have infected 1.8 others.