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Why bars are hot spots for COVID-19 transmission

Scientist explains how concentrations of COVID-19 can build up indoors within hours

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Recent reopenings and hasty reclosings of bars in Arizona, Florida and Texas and other states raise the question of whether bars are hot spots for COVID-19. Scientists and doctors offer reasons why drinking in a bar can be dangerous.

Social distancing for COVID-19 is often forgotten at bars

When you drink, you’re more likely to forget about the virus and social distancing standards. 

"Alcohol lowers your inhibition and judgment, and in the setting of loud music in a bar or nightclub, often makes you move closer to other people,” says Dr. Robert Glatter, E.R. physician at Lenox Hill Hospital in New York. 

Simply talking to someone a short distance away poses a threat of viral transmission. Dr. Julian W. Tang, associate professor at the University of Leicester in the U.K. conducted a post-pandemic flu study examining how temperature differences in warm exhaled air could be used to visualize different types of airflows produced by human volunteers.

This phenomenon can be viewed by two related airflow visualization methods, known as Schlieren and shadowgraph photography. The study used both methods to show how breathing, talking, laughing, singing, coughing and sneezing could carry air (and any virus it contains) to other people within a 3-foot distance. 

“This study was originally conducted during 2010-12 after the 2009 flu pandemic, but it has developed a new relevance now in the current COVID-19 pandemic,” Tang says. The video below shows what it looks like when two people are talking:

In a poorly ventilated bar, the COVID-19 virus can accumulate

Tang  co-authored an open letter to the World Health Organization urging officials to acknowledge that the virus is transmitted via aerosols. The letter also asks the WHO to focus on improving ventilation and air filtration in public places such as bars. 

“Ventilation is the key control point for an airborne virus – and this is already in existing infection control guidance under the CDC's 'Engineering Controls',” Tang says. “Based on multiple studies done by the authors of this paper, we believe that optimizing ventilation is the way to move forward: to remove the virus from the air before people inhale it." 

Tang explains in the example below how, in the absence of effective ventilation, the virus can fill a bar in a matter of hours:

Leaning in to hear increases COVID-19 risk

In many bars, loud music or noisy crowds force you to move closer to hear. 

“When I’m in a loud situation, I tend to turn my head or my ear towards that person's mouth, but then their exhaled breath comes straight towards my face, ” Tang says. “It makes me inhale even more of the air that they are exhaling that could be carrying virus. And louder speaking also expels more droplets.”

Laughing, singing, and loud voices expels more COVID droplets

People often laugh and sing when they drink, which produces larger exhalations than talking.

"As people become intoxicated, they tend to talk louder, tell jokes or sing, which spreads more droplets," Tang says. "If you are telling a joke surrounded by people laughing in response, you may get much more exposure to their exhaled air that may be carrying virus because they are laughing towards you."

It’s impossible to drink something while wearing a mask

"Without close monitoring to wear masks and practice social distancing, bars are certainly one venue ripe for transmission of the virus,” Glatter says.  "Bars are inherently one setting where social distancing is quite difficult to practice and enforce, primarily the result of alcohol's effects on social interactions."

A recent Twitter post from the Texas Alcoholic Beverage Commission shows an overcrowded scene at a Houston bar that was later closed. Few people were wearing masks or practicing social distancing:

Since it is difficult to mask and maintain social distancing inside, one way to reduce your risk is to take the party outside. 

“There are three factors that are very effective in reducing transmission risk when outside," Tang says. "First there’s a massive air dilution, so the virus will have more air to spread into. Second, if there is wind, this further dissipates the virus. Third, sunlight will damage the virus so it cannot replicate. So my message in the new COVID-19 normal is: 'Have fun - safely!'"

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