UDY WOODRUFF: As we have been mentioning, the U.S. has passed yet another tragic marker
in the pandemic.
More than 200,000 people have died in this country from COVID-19 and related complications.
That, in a period of less than eight months, is nearly twice as many Americans who have
been killed in every major conflict since the Korean War combined.
Our understanding of how the coronavirus is spreading continues to evolve. We want to
use this moment to clarify much of the latest scientific thinking.
First, a report from Stephanie Sy, followed by a conversation with William Brangham.
WOMAN: The coronavirus can remain infectious on plastic and steel surfaces for up to three
days.
WOMAN: That has many people worried about shopping and other everyday tasks.
MAN: Because you have got to be putting that disinfectant on these groceries.
STEPHANIE SY: This was the sound of fear early in the pandemic, after studies showed that
the novel coronavirus could live on surfaces for hours, even days.
It led to a furious wave of scrubbing, disinfecting and sold-out cleaning supplies across the
country.
DR. EMANUEL GOLDMAN, Rutgers New Jersey Medical School: But the problem with those experiments
is that they didn't relate to what a real-life scenario would be like.
STEPHANIE SY: That's Dr. Emanuel Goldman, a microbiologist at Rutgers New Jersey Medical
School.
In July, he published this article in the British medical journal "The Lancet" arguing
that these early studies greatly exaggerated the amount of virus that could actually be
found on surfaces in the real world. He pointed out that the lowest amount of infectious particles
researchers used to test surfaces in the lab was 10,000, a huge amount.
DR. EMANUEL GOLDMAN: You would need something like 100 people coughing or sneezing on the
same small surface area to get anywhere near the amount of virus that they used in these
experiments.
STEPHANIE SY: He says these mistakes, and a lack of scrutiny, have siphoned limited
resources from everything from subway systems to schools for excessive deep cleaning that
shows little evidence of helping prevent COVID spread.
DR. EMANUEL GOLDMAN: Our mothers taught us, you go to the bathroom, you wash your hands.
You prepare food, you wash your hands. You touch something dirty, you wash your hands.
That's all you have to do.
Normal, routine hygiene is sufficient to protect against this virus.
STEPHANIE SY: Meanwhile, he adds, not enough money and attention have been paid to what
we now know is the primary way the virus travels: the air.
DR. EMANUEL GOLDMAN: A teacher from a school system saying they were going to shut down
the schools one day a week for deep cleaning and disinfection. Wouldn't it be better to
use it instead on ventilation systems or hiring more teachers, so you could have fewer students
per class?
DR. SHELLY MILLER, University of Colorado Boulder: You want to try to replicate the
outside, indoors, in your space.
STEPHANIE SY: Dr. Shelly Miller is an environmental engineer at the University of Colorado Boulder.
For decades, she's studied the way pollutants and infectious diseases spread in indoor spaces,
and over the summer helped her own university prepare for when students and faculty return
to campus.
DR. SHELLY MILLER: You want to control the source of the contaminants. And, in this pandemic,
the sources are the infectious people inside. And so, to control the release of virus, you
want to wear a mask, and you also want to be outside of their personal cloud.
But some of the virus can potentially leak into the environment, and then you have to
clean the environment. And the way to do that is the filtration and ventilation.
STEPHANIE SY: The simplest way to do that, she says, open a door or window.
But in many parts of the country where it's still too hot, or becoming too cold, to do
that, Miller says there are different ways to increase a building's mechanical ventilation
and filtration.
Here's a basic guide: Buildings up to code should already be replacing the inside air
with outside air three times an hour. But with coronavirus, that should be doubled,
to six exchanges per hour, and, ideally, to nine exchanges per hour.
And, crucially, the more people there are contained in a space, the more exchanges are
needed. HEPA filters, which stands for high-efficiency particulate air, should also be added to ventilation
systems to increase protection.
If I walk into a restaurant or a classroom, is there a way for me to personally tell if
that is a safe place to be, if there's enough ventilation?
DR. SHELLY MILLER: Unfortunately, at this point in time, no. And that is why, a lot
of times, I have been saying, well, we really need to address this. We need to give buildings
and classrooms and other facilities resources, so they can -- so they can let the public
know how they have attended to this.
STEPHANIE SY: She and others say the Centers for Disease Control and Prevention and the
World Health Organization have been too slow to move away from early guidance on surface
disinfection, and towards clearer guidance on preventing airborne transmission.
Last Friday, the CDC did add language on its Web site about aerosols from coughing or breathing
spreading the virus, and the need for ventilation, then suddenly removed it.
DR. SHELLY MILLER: So, the only rule of thumb I can say is, if you walk into a space and
it feels hot and stuffy in there, and you can smell smoke and you can smell different
odors, then it's probably not ventilated enough, and you probably shouldn't spend very much
time in there.
STEPHANIE SY: Even portable air cleaners can help, and Dr. Miller and her colleagues have
created a guide for schools on these, which you can find on our Web site.
The bottom line: If you're thinking about going back to the gym, to a restaurant, your
office or school, keep washing your hands, keep wearing your mask, and keep social distancing.
But don't let those deep cleans fool you. Ask what they have done about the air.
DR. EMANUEL GOLDMAN: The problem is that it's been out there for so long, and Shakespeare
said it the best, what's done cannot be undone. And it's going to be a long time to turn the
ship around, if ever, because a lot of people still are operating on these assumptions.
STEPHANIE SY: For the "PBS NewsHour," I'm Stephanie Sy in Phoenix.