A computer model of the cruise-ship outbreak found that the virus spread most readily in microscopic droplets light enough to linger in the air.
“The smaller droplets are also more likely to penetrate deeply into the respiratory system, down to the lungs. It may take a much smaller viral load — fewer viruses — to cause infection in the lungs than higher up, such as in the throat. This, at least, is the case for other respiratory viruses, like the flu.”
“To me, this is an all-in moment,” Dr. Allen said. “We need better ventilation and better filtration, across the board, in all our buildings.”
We also found that especially with very small aerosols — smaller than 1 micron — it is more effective to use a softer fabric (which is easier to fit tightly over the face) than a stiffer fabric (which, even if it is a better filter, tends to sit more awkwardly, creating gaps).
Infected children have at least as much of the coronavirus in their noses and throats as infected adults, according to the research. Indeed, children younger than age 5 may host up to 100 times as much of the virus in the upper respiratory tract as adults, the authors found.
“It definitely shows that kids do have levels of virus similar to and maybe even higher than adults,” Dr. Heald-Sargent said. “It wouldn’t be surprising if they were able to shed” the virus and spread it to others.
The virus is shed from the upper respiratory tract, not the lungs, she noted.
“We are going to be reopening day care and elementary schools,” she said. If these results hold up, “then yeah, I’d be worried.”