9 Things Experts Have Learned About Covid-19 So Far
The disease has not changed, but scientific understanding has evolved dramatically
The first documented case of Covid-19 in the United States was reported half a year ago, days before early warnings from the U.S. Centers for Disease Control and Prevention (CDC) that a “very serious public health threat” loomed. Yet health officials had only a rough idea of how the novel coronavirus spread, who the disease affected most, and how to best combat transmission and provide treatment.
Public messaging on the seriousness of the virus was at times conflicting and confusing, including the early advice not to wear masks. Six months later, scientists have a firm handle on how the virus spreads and what should be done to get the pandemic under control.
Here are nine things we know about Covid-19 now that we didn’t know then.
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The virus can become airborne
Then: Early advice from the CDC emphasized hand-washing, disinfecting surfaces, and sneezing into your elbow, on the assumption that the coronavirus spread mostly through handshakes, contact with infected surfaces, and through close contact with infectious people (within six feet).
Now: After months of scientific discussion and study, and some confusing communication to the public, the experts agree: The virus can become airborne — within tiny, suspended droplets called aerosols — and infect people beyond six feet, especially in poorly ventilated indoor spaces, where the aerosols are trapped and build up. The World Health Organization, after six months of mounting evidence, finally agreed with scientists on this point. The risk outdoors is lower, the experts still say, but not zero.
What it means: Covid-19’s many ways of spreading vex all but the most stringent efforts to control transmission, particularly indoors. This is why health experts implore people to avoid large crowds, observe physical distancing, wear…