The Presidential Debate Commission is taking extra precautions during the Vice-Presidential Debate Wednesday night amid the coronavirus outbreak in the White House. Some epidemiologists and airborne pathogen specialists scratch their heads over pictures of two curved plexiglass barriers they want to use.
Vice President Mike Pence and Senator Kamala Harris will sit more than 12 feet apart and will be separated by two plexiglass barriers. However, these barriers are "entirely symbolic," said Dr. Bill Schaffner, an epidemiologist at Vanderbilt University.
The commission became concerned after President Donald Trump and several White House staff signed Covid-19 shortly after the presidential debate last Tuesday. The Centers for Disease Control and Prevention said Pence was not in "close contact" with Trump, who announced he was infected with the virus early Friday morning.
One person familiar with debate planning told NBC News that Harris' campaign called for the use of the plexiglass at the event at the University of Utah in Salt Lake City.
The plexiglass is "minimal protection," said Schaffner in a telephone interview, adding that the barriers are mostly "cosmetic".
However, he added that barriers are part of a "layered approach" that involves testing and distancing everyone on stage. Those in the discussion room must wear a mask and there will be no handshakes or physical greetings between Pence and Harris, according to the commission. Overall, the steps would likely have reduced the risk of spread.
The plexiglass barriers are only "part of the CPD's overall approach to health and safety" according to an information sheet distributed by the commission.
The debate should take place indoors and of course there is a lot of talk. This is important as the CDC released new guidance on Monday that states that the virus can spread through airborne particles between people who are more than two meters apart in certain environments. The CDC said the risk of this occurring increases indoors and during certain activities, including speaking.
Jeff Siegel, professor of civil engineering at the University of Toronto and a specialist in indoor air quality, ventilation and filtration, said the risk of virus-containing particles being aired in an environment like a debate when people speak loudly is "enormous". ""
"On the plus side, it's a pretty big room so there's a big thinning effect," he said on the phone, adding that Harris, Pence and presenter Susan Page will be kept a reasonable distance from one another. The high ceiling and large space will also help reduce the risk, he said.
"But they don't deal with things like ventilation," Siegel said, hoping the discussion room had enough up-to-date air filtering and ventilation systems. "If I were a Vice President Pence or Harris employee, I would definitely want a portable HEPA filter."
HEPA filters are powerful air filters that trap very small particles in the air. The Commission has not returned CNBC's invitation to comment on the building's filtration and ventilation system.
Kimberly Prather, a distinguished professor of atmospheric chemistry at the University of California at San Diego, said if Pence is contagious right now, the risk of passing it on to Harris will increase as the debate progresses.
"Imagine you are in a room with a smoker," said Prather, White House coronavirus advisor Dr. Anthony Fauci, informed about the risk of airborne spread, in a telephone interview. "Over time, the longer you sit in this room, the only thing you will see is how the haze builds up."
Prather explained that the risk of airborne spread was due to virus-containing aerosols, very small particles that float in the air and can even move through currents. The CDC claims that most transmission occurs through larger breath droplets, but Prather has long warned of the risk of aerosol spread.
"The louder you speak, the more you produce," she said of aerosols, adding that without adequate ventilation, those plexiglass barriers don't do much to stop the particles. "When I saw it, I laughed, but it's not funny."
Prather added that she and her colleagues are concerned about the type of message the barriers are sending to the public. She said people and businesses should focus more on air filtration and ventilation than building barriers, although the two strategies can be implemented together. Prather hopes Harris and Pence will wear a mask throughout the debate.
"There is no reason not to do this," she said.
Jose-Luis Jimenez, a chemistry professor at the University of Colorado at Boulder who studies how aerosols spread the virus, shared Prather's concern about the message this sends to the public. He said the debate should be moved outside to send the message that "any activity that can be moved outside should be done outdoors with sufficient clearance".
"Perhaps the ventilation rate in this discussion room is very high, so the risk to the debates is low. But they are sending the message to millions of people that speaking indoors without a mask is safe as long as there is enough distance," he said in an email. "These barriers are a joke. It's just theater to make it look like they're taking some precautions."