Plexiglass at VP debate won't keep candidates safe, health experts warn. Masks might.

The clear plexiglass partitions dividing Vice President Mike Pence from Sen. Kamala Harris during Wednesday's vice presidential debate won't do much to prevent the spread of COVID-19, health experts warn.

Using plexiglass dividers in this situaiton is based on an outdated understanding of how the coronavirus spreads, scientist Kimberly Prather told USA TODAY on Wednesday. There are much more effective ways for the candidates to protect themselves, including wearing masks during the debate, Prather said.

Plexiglass dividers were always intended to stop large droplets of the virus, but at the distance the candidates will be spaced apart — more than 12 feet — such droplets aren't much of a danger, she said. Prather, an atmospheric chemist and professor at the University of California San Diego, coauthored a letter on airborne transmission of the coronavirus that was published this week in Science Magazine.

She said it's important for people to understand the difference between droplets and airborne transmission through aerosols — and that masks are effective reducing the risk of both.

It has long been accepted that the virus can spread through relatively large droplets: That's the source of the ubiquitous 6-foot of social distance rule. More recently, it has become widely accepted that the virus can spread through tiny aerosols, which can float in the air for longer periods of time.

This week, the Centers for Disease Control and Prevention updated its website to warn the coronavirus can spread this way, something public health experts have been warning about for months but went unacknowledged by the agency until Monday.

Prather encouraged people to think about cigarette smoke when they consider the risk of being infected with the virus in a given situation.

In the case of Wednesday's debate, if one of the candidates was smoking for the duration of the 90 minute debate, it would be reasonable to suspect the other candidate would inhale some second-hand smoke — plexiglass divider or not.

Even worse, a poorly placed plexiglass divider can “trap the air,” making it a more dangerous situation for virus spread, Prather said. In addition to masks, better ventilation or even portable air filters are a more effective way to keep the candidates safe, she said.

Multiple other experts shared similar concerns with the New York Times ahead of the debate. An opinion column in the Washington Post notes the dividers may serve a symbolic importance, as a sign the candidates are taking the risks seriously.

The Commission on Presidential Debates previously announced new rules for the vice presidential debate that included plexiglass on the stage inside Kingsbury Hall at the University of Utah. Changes came in response to President Donald Trump and several other GOP allies testing positive for COVID-19 two days after the presidential debate in Cleveland last week.

The Harris campaign said Harris will follow the protections recommended by health experts including plexiglass on her side of the debate stage.

"Senator Harris will be at the debate, respecting the protections that the Cleveland Clinic has put in place to promote safety for all concerned," said Sabrina Singh, Harris' press secretary. "If the Trump administration’s war on masks has now become a war on safety shields, that tells you everything you need to know about why their COVID response is a failure."

Vice President Mike Pence has pushed back at the plans, according to a report from the Washington Post.

Contributing: Joey Garrison and Adrianna Rodriguez; The Associated Press

This article originally appeared on USA TODAY: Plexiglass at VP debate won't keep Mike Pence, Kamala Harris safe