As CDC warns of coronavirus’s spread in US, officials reveal that more than 600 in Mass. have been monitored for illness

A pedestrian wore a face mask walked along a street in the Flushing Chinatown neighborhood in the borough of Queens in New York.Stephanie Keith/Bloomberg

More than 600 Massachusetts residents who traveled to China recently have voluntarily quarantined themselves at home while being monitored for the novel coronavirus, health officials revealed Wednesday.

So far, 377 have completed the quarantine without falling ill, and 231 are still being monitored, Public Health Commissioner Monica Bharel said. Only one Massachusetts resident — a Boston student — contracted the illness, and he is recovering well in isolation at home, Bharel said.

The quarantines are voluntary and last 14 days. People have been cooperative in staying home, communicating regularly with their local health departments, and taking their temperature daily, she said.

The numbers were provided for the first time in a telephone press briefing Wednesday. Previously health officials have said they would discuss only confirmed cases.

On the call, held in response to federal officials’ statements Tuesday urging people to get ready for the virus’s likely spread in United States, Bharel offered repeated assurances that Massachusetts is well-prepared to handle an outbreak of the new coronavirus, known as Covid-19.

Supplies of personal protective equipment for health care providers are adequate, as is funding for the state’s response, she said.

As for what individuals should do in response to Tuesday’s warning from the US Centers for Disease Control and Prevention, Bharel said the advice hasn’t changed: Take normal precautions against infection by washing hands, covering coughs, and staying home when sick.

“The risk of Covid-19 remains low in Massachusetts,” Bharel said. “People should live their lives normally and go about their normal activities.”

If the virus started spreading within Massachusetts, measures such as cancellation of mass gatherings may be recommended, Bharel said.

But she declined to provide details on what would trigger such a call or other measures except to say that the state would follow federal guidance.

“When we look at this current Covid-19 situation, we don’t speculate on how or when it will spread,” she said. “We’re preparing for whatever comes our way in Massachusetts.”

The CDC’s warning provided little guidance on what actions people should take to prepare, nor exactly what scenarios to prepare for. It coincided with the news that the Covid-19 was gaining strength in Europe for the first time, with an outbreak Italy affecting more than 300 people. That prompted Emerson College to cancel a trip to Milan and Endicott College to offer to bring study-abroad students home.

The health department on Monday sent a letter to school administrators advising them how to respond in the unlikely event they encounter a student who has recently returned from China and has symptoms, and recommending routine disease-prevention steps.

“What we would like schools to do is review that guidance,” Bharel said. “If there’s any need for anything like cancellation, we would give detailed guidance. At this time it is safe for children in Massachusetts to go to school.”

The news that hundreds of Massachusetts residents are quarantined at home, however, highlights the challenges others may face if the virus spreads.

If a coronavirus outbreak occurs, people may be asked to stay home to slow the spread of illness, said Leonard Marcus, co-director Harvard’s National Preparedness Leadership Initiative, which trains leaders to respond to crises.

It’s advisable to think through what you need to have in the house if that happened, he said.

“I wouldn’t stop life — just be aware it’s time to be thinking about those things,” said Marcus. “It’s worth going through the mental exercise. It’s worth taking a few steps.”

Think about what you need on hand if you have to stay home for a couple of weeks, especially food and medications, Marcus said. He sees no urgency in stocking up, though. “If you’re at the store and you’re shopping, buy a couple of extra items just in case. Most importantly don’t panic; this isn’t yet a crisis,” he said.

Also, Marcus urged, contemplate your responsibilities. Does an elderly neighbor or parent depend on you for care? Who can pick up the ball if you can’t get to them?

Any requirement to stay home most likely would apply to limited areas where the virus was being transmitted. Quarantining everyone in Boston “would only be done if we were finding the potential for hundreds of thousands of cases in Boston,” Marcus said. “I want to emphasize there’s a chance of this happening. Nobody can say for sure what is the real chance of it happening.”

Dr. Eric Toner, a senior scholar with the Johns Hopkins Center for Health Security, said that Covid-19 outbreaks in the United States are likely and could be severe. But the risk to individuals is small, he said.

“For an individual who is otherwise healthy, this is probably no more dangerous to you than the flu,” Toner said. “But to the health care system this could be really bad as bad or worse than a severe flu pandemic and it’s a threat to the elderly and people in long term care facilities.”

If hospitals are overwhelmed with Covid-19 patients, they will struggle to meet other health care needs, he said. Elective surgeries may be postponed.

Nursing homes will face a particularly tough challenge, because their old and sick patients are most susceptible to Covid-19 and live in close quarters where the virus can spread easily, Toner said.

Canceling mass gatherings might slow an epidemic, should one occur, and it would be worth the disruption because “it doesn’t cause a great deal of societal or economic harm,” Toner said.

But sometimes the reaction to an outbreak does more damage than the disease itself. Closing schools, for example, would be “tremendously disruptive to the economy” as parents miss work, Toner said. And it might not slow the illness, because children don’t seem to be vulnerable to Covid-19.

Dr. Irwin Redlener, director of the National Center for Disaster Preparedness and professor health policy and management at Columbia University, also cautioned against overreacting. It’s too soon to start stockpiling cans of beans in the basement, he asserted; that “creates an unnecessary amount of panic.” Taking overly strong measures can do more harm than good. “If we overdo it, the other consequences for the economy and education could be a very unfortunate thing,” Redlener said.

Dr. Nahid Bhadelia, assistant professor at Tufts University’s Fletcher School and medical director of the Special Pathogens Unit at Boston University School of Medicine, has worked in Ebola treatment units in Africa. She noted that Ebola epidemic was devastating to West Africa — even though less than one half of 1 percent of residents became ill. School and business closings had more far-reaching effects. “That’s really what pandemics do,” she said. “It’s a not a direct impact. It’s an indirect impact.”