[The Atlantic] The Trouble With Hard Numbers During Uncertain Outbreaks
Fourth, R0 is not easy to calculate. That's especially true in the early days of an epidemic, when it's not even clear how many cases there have been. Some people might have been infected without showing symptoms. Others might not have reported their symptoms to health authorities. Absent clear data on who has the disease, let alone how they're moving around and interacting with other people, scientists have to calculate R0 by doing complicated simulations using a variety of possible methods. That's why early estimates can vary so wildly, and why they should be taken with a grain of salt.Read: A historic quarantine
Fifth, R0 is not some magical, immutable property of the virus itself. It depends on how likely someone is to be infected after contact with an infectious person, and how often such contacts occur-and these quantities are also affected by how societies deal with a virus. When SARS first emerged, transmission dynamics played out very differently in China and Canada, which is why the virus's R0 values cover a wide range from 2 to 5. "In places with good infection control, where you can isolate cases as soon as they happen, you'll see a lower R0 than say in places where an outbreak initially took off," says Majumder.
The current R0 estimates for the new coronavirus are specific to Wuhan, and mostly to the era before people knew about the virus. New estimates will emerge as the virus spreads to places that are now aware of and watching for it. "Likely, these will all be significantly lower," says Kristian Andersen, a virologist at Scripps Research Translational Institute.
Sixth, R0 is not destiny. It is a measure of a disease's potential. And once nations realize that a new disease exists, they can actively screen for it, check that health care workers are using proper protection, or instigate quarantines. Even simple steps like hand-washing might make a difference. All of these measures could potentially lower the chances that the virus will spread and ensure that its actual transmission rate-the quantity known simply as R-is less than R0, and ideally less than 1. There are a few reassuring signs: One study suggests that patients are now being isolated just one day after showing symptoms, as opposed to after six days at the start of the outbreak.
None of this should be cause for complacency. The new virus is a serious threat, and the world should absolutely start considering what to do if containment measures fail. But at a time of great uncertainty, people grasp for solid answers, and numbers seem to offer them.
This new virus has emerged at a time when scientists have more avenues than ever for publishing their data and comparing notes. That can be a good thing, since fast and open communication can help to bring diseases to heel more quickly. The risk is that a complicated number is released without context into a world that doesn't know how to think about it. "Getting these R0 values out very rapidly is super important," says Andersen. "But the way that some people and news outlets have interpreted what they mean... that part is problematic."
We want to hear what you think about this article. Submit a letter to the editor or write to [email protected]
Ed Yong is a staff writer at The Atlantic, where he covers science.
By the numbers: Economic effects of China coronavirus Aljazeera.com
More News in Health
SINGAPORE - Raffles Medical Group (RMG) is investigating the source of a photo that shows the identity card of a patient who was allegedly a suspected Wuhan virus case and a letter from its clinic
The Ministry of External Affairs informed that the Indian Embassy in Beijing is in touch with Chinese authorities and preparations were underway to evacuate Indians affected by the coronavirus in China's Hubei province.
The rapid spread of the deadly coronavirus has been turned into a map, with China today confirming another 25 deaths from the viral illness. The map was created by Johns Hopkins University as a response to
China has confirmed more than 4,500 cases of a new form of coronavirus, with 106 deaths. Nearly all of the fatalities have been in central Hubei province, but the new total includes the first death in