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发帖数: 2599 | 1 https://www.nejm.org/doi/full/10.1056/NEJMp2003762
www.nejm.org/doi/full/10.1056/NEJMp2003762
Now we also face an immediate crisis. In the past week, Covid-19 has started
behaving a lot like the once-in-a-century pathogen we’ve been worried
about. I hope it’s not that bad, but we should assume it will be until we
know otherwise.
There are two reasons that Covid-19 is such a threat. First, it can kill
healthy adults in addition to elderly people with existing health problems.
The data so far suggest that the virus has a case fatality risk around 1%;
this rate would make it many times more severe than typical seasonal
influenza, putting it somewhere between the 1957 influenza pandemic (0.6%)
and the 1918 influenza pandemic (2%).2
Second, Covid-19 is transmitted quite efficiently. The average infected
person spreads the disease to two or three others — an exponential rate of
increase. There is also strong evidence that it can be transmitted by people
who are just mildly ill or even presymptomatic.3 That means Covid-19 will
be much harder to contain than the Middle East respiratory syndrome or
severe acute respiratory syndrome (SARS), which were spread much less
efficiently and only by symptomatic people. In fact, Covid-19 has already
caused 10 times as many cases as SARS in a quarter of the time. |
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