Coronavirus will swamp the US if urgent action isn't taken, warn scientists: 'No easy way out'
They also suggest that parts of the country without large clusters of cases could still avoid the worst of the outbreak if they impose strict measures
Researchers at Columbia University, New York, have warned that strict measures to limit social contact are necessary for parts of the United States to significantly stem the tide of illness and death in the coming months due to the novel coronavirus (COVID-19) outbreak.
With at least 26,680 people having tested positive, the country has stepped up testing efforts over the past week. The death toll stands at 340 due to the virus.
The researchers used The New York Times database of known cases and the Census Bureau's transportation data to model how the outbreak could evolve, based on known information about the virus. Different scenarios were plotted depending on the measures the country could adopt to control the outbreak.
According to The New York Times, even if the country cuts the rate of transmission in half, which is considered to be unlikely, around 650,000 people might become infected in the next two months. This finding comes from considering those with mild symptoms who are carrying and spreading the disease without being aware that they have it. The number of undetected cases — 11 times more than has been officially reported, the researchers estimate — reflects how far behind the United States has fallen in testing for the virus.
One scenario — which is unlikely as it is the worst-case situation — simulates what could happen without any intervention. A second scenario envisions what would happen with some control measures, such as partial adherence to social distancing guidelines and a patchwork of government-imposed restrictions on work, travel and public gatherings. A third assumes severe control measures: strict adherence across the country to social distancing, working remotely, closing schools and restaurants and banning large gatherings.
New York City, Seattle, Boston and parts of California already have such large outbreaks that they will probably see significant increase in cases even after taking extraordinary measures over the past week, according to the researchers.
They also suggest that parts of the country without large clusters of cases could still avoid the worst of the outbreak if they impose strict measures such as closing schools, banning mass gatherings and testing and quarantining sick people and their contacts. The outbreak would then spread inland at a much slower pace and strike with less severity, the estimates say. But controls would need to be put in place immediately, and everywhere.
"We're looking at something that's catastrophic on a level that we have not seen for an infectious disease since 1918," said Jeffrey Shaman, a professor of environmental health sciences at Columbia and the leader of the research team told The New York Times, referring to the Spanish influenza pandemic. "And it's requiring sacrifices we haven't seen since World War II. There are going to be enormous disruptions. There's no easy way out."
While states such as New York, Illinois, California, Connecticut and New Jersey have imposed "stay-at-home" executive orders, other states are yet to follow suit. The researchers warn that if the country as a whole does not take collective action, many counties could see a significant proportion of their populations infected with the virus.
Researchers from other institutions agreed with the findings. "You have to think of this as an insurance for the future: The earlier you do it, the greater effect you have on the virus," Alessandro Vespignani, director of the Network Science Institute at Northeastern University told The New York Times. "It’s better to take excessive precautions than not."
The researchers used observations to infer the key features of the outbreak. One is how many people each person has infected so far — an average of 2.2. Another is how many people may pass on the virus without knowing that they have it. The disease is spreading far too fast to be explained by known cases alone and only about 1 in 11 infections has been reported, they found.
Those factors allow the researchers to simulate the spread of a virus in the future. They adjust those simulations under different scenarios in which the nation imposes a range of control measures to stop the spread. The estimates are acknowledged to be imperfect, but they are consistent with the available data. It is impossible to know the exact number of cases a week ago or to predict the future.
It is also impossible to model the precise impact of unprecedented measures that America has already put in place to control the outbreak. But the research estimates that if measures to slow the disease are not effective, the virus could sicken millions of people or more, losing steam on the coasts in May before spreading to the rest of the country over the summer.