By Louisa Moller

BOSTON (CBS) — An Infectious disease expert is warning that protests to the police killing of George Floyd in Boston and around the country may cause a new wave of coronavirus cases.

“We still think there are probably two or three people in a hundred walking around with the virus. And the crowds I saw there were several hundred people you could see in a large group,” said infectious disease expert Dr. Richard Ellison, referring to the Boston protests.

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Ellison, who works for UMass Memorial Healthcare, worries the sheer size of the rallies and the closeness of participants is putting people at risk of contracting the virus even though they are taking place outside, where the virus can disperse.

“I do think that there’s going to be some individuals that will pick this up from going to these rallies,” Ellison said.

Loud talking, singing and chanting only increases the spread and the use of tear gas and pepper spray can cause people to sneeze and cough.

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“When sneezing or coughing you can spread eight to 10 feet, you’ll spread the large droplets,” Ellison said. “The louder someone is speaking the bigger the risk. That’s going to tend to spread more droplets from our mouth into the air.”

History also shows the damage. In 1918, the city of Philadelphia held a parade to commemorate World War I. The dense crowds ended up contributing to a massive outbreak of the flu.

In the case of the coronavirus, Ellison said we may not realize the impact of the protests for two weeks.

“The average time between the time someone gets exposed until they develop symptoms is about 5 days and it can go out to about 14 days. So, we’re not going to see something tomorrow or the day after tomorrow. We’re going to start seeing something next weekend or the following week,” he said.

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Ellison said protesters can do so safely if they wear masks and stay six to eight feet apart.

Louisa Moller