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It's too late to fight Covid-19 in US by curbing travel

Washington

CHINESE authorities banned flights and cut off rail and highway travel to quarantine the city of Wuhan, a city of 11 million people who are mostly confined to their neighbourhoods by the coronavirus outbreak.

In the US, the virus has already spread so far that experts say such draconian limits on domestic travel probably wouldn't be effective. But the outbreak could still have widespread effects on transportation as people opt to stay home and transit workers call in sick.

"When you're dealing with an influenza virus-like transmissions, it's like trying to control the wind," said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at University of Minnesota.

"People may want to try to limit their time in large crowds, but I don't think that a domestic limitation on travel is going to help at all."

At least 100 coronavirus cases have been confirmed in the US.

Six deaths linked to the virus have been confirmed in Washington state, most clustered around a nursing home. The state is preparing for a wider outbreak to take place and setting up isolation centers for patients.

Dr Osterholm and other experts say cutting off transportation options would do little to blunt the further spread of the virus, and may cause more harm than good. For one, the appearance of the novel coronavirus in 10 states from New York to California with more cases expected has all but neutered the potential of travel restrictions to contain the virus, Dr Osterholm said.

"This virus is already all around the country," he said. "Think of this like seasonal influenza. We have regions that in any given week have more activity than other regions, but by the time the entire season is done, it's covered the entire country. And when was the last time anyone thought of quarantining the United States for seasonal influenza?"

President Donald Trump told reporters on Tuesday that he isn't considering domestic travel restrictions due to the virus as international health officials also downplayed their potency.

"Countries that rely purely on travel measures as their only health defense will have a weak defense," said Mike Ryan, head of the World Health Organization's health emergencies programme. Travel restrictions should be proportional to the risks a country is facing, he said.

Prior research also suggests travel restrictions have limited effect. A 2011 study examining a theoretical influenza epidemic in New York City found that people infected on the subway accounted for only 4 per cent of all infections, and that efforts to prevent transmission on subways did little to dampen the broader outbreak.

A separate study in 2006 found that imposing border restrictions along with domestic travel restrictions were unlikely to delay the spread of an influenza pandemic by more than a few weeks.

Travel restrictions might make sense as a means to contain a large outbreak in one city or region if other areas are less affected, said Jeff Schlegelmilch, deputy director of the National Center for Disaster Preparedness at Columbia University. Officials weighing such a move would have to compare the costs of inaction against those of restricting access to a city.

"If done correctly, it can slow the transmissions, and again that's what all of these are about. It's not about stopping it, it's about slowing it," he said. "Whether or not it's a good idea depends on a lot of other factors."

For example, imposing restrictions on domestic travel also risks cutting off critical supplies when communities need them most, he said.

"There's always a trade off between disrupting transportation and disrupting access, and in today's world where things move so fast, it seems that the costs of quarantining or of shutting down areas can be even greater than it used to be because we rely on so much from the outside," he said.

Those trade-offs and others were highlighted by the George W Bush administration in a 2006 report summarising how the federal government would respond to an influenza pandemic. For one, the report noted that people could get around flight restrictions by taking their car or a train.

The 233-page report by the White House's Homeland Security Council suggested some of the largest transportation impacts of the virus will be caused by regular people, rather than government restrictions.

Absenteeism during an influenza pandemic could limit transportation services, it warned. In addition, "passenger transportation will likely decrease as the public opts not to travel due to possible exposure. This will likely begin in international aviation, cruise ships, and highway border crossings. Once cases are present in the United States, this decrease in passenger travel will occur domestically in private automobile, aviation, mass transit, passenger rail, and motor coach travel," the report said.

It also warned that closing state or local borders would be "highly unlikely" to be effective, and could cause shortages of key supplies.

"If you're in a situation where you have sustained community wide-transmission that is of a significant threat to people's health, if you have a high fatality rate, and the value of restricting travel is greater than the cost of that disruption, that's when you would want to employ it," Mr Schlegelmilch said. "I don't think we're anywhere near that right now." BLOOMBERG