PITTSBURGH (KDKA) – The crowd on Sunday at Heinz Field for the Steelers vs. Raiders game will probably be the largest in one place since the pandemic began and the experts say they will be entering a high-risk environment for Covid spread.

Johns Hopkins infectious disease specialist Dr. Amesh Adalja says the outdoor environment reduces the risk, but the elbow to elbow seating and the atmosphere create risks.

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“When people are vociferous when they are talking yelling and screaming and cheering,” he says. “They’re going to be disseminating respiratory droplets out of their mouth out of their nose, and that poses a transmission risk.”

Dr. Adalja says the weather could help.

“The more windy it is, the more blustery it is, the more ventilation you’re likely going to see and some of those respiratory particles will get whisked away faster,” he explains.

But he points out the no mask and no vaccine required in the seating area rules don’t help with mitigation.

“There’s always going to be some level of transmission when you have people in a high-risk environment and you don’t have everybody vaccinated there,” he says.

CBS News medical expert Dr. David Agus agrees.

“You know, I think we have to use caution is that I really hope that everyone who goes to that game is double Vax, or had got the J&J vaccine,” Dr. Agus says.

Dr. Adalja adds, “Heinz Field could solve this problem by requiring vaccination as a condition of entry, they could solve it overnight, and make it a much safer venue than it would be.”

After fans in Buffalo mostly ignored masking rules similar to Heinz Field on Sunday, the Bills have decided to require vaccination.

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The Seahawks and Raiders already require full vaccination proof and the Saints require fans to have had at least the first dose.

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The Steelers are not currently changing their policy for Heinz Field which requires only masking in indoor areas.

“I really hope that they still wear a mask, even though it’s optional,” Dr. Agus says.

Dr. Adalja adds, “Wearing a mask in those situations would decrease their personal risk of acquiring the virus. Along with being vaccinated and being around vaccinated individuals.”

So how do you know who’s vaccinated and who’s not? Dr. Adalja says to be proactive.

“I do think it’s a good practice to ask people if they’re vaccinated, especially those within kind of a six, six feet, the perimeter of view because that’s where the highest risk transmission would be,” he explains.

Six feet would be about two or three people on each side of you and rows forward and two rows behind.

Of course Dr. Agus says to be truly safe, “I really hope that if you’re vulnerable you have other medical conditions you say, ‘hey, it’s just not worth the risk right now I’m going to stay home.’ And let other people go who have been vaccinated and don’t have these conditions.”

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Dr. Adalja says the NFL should mandate vaccines and take the pressure off the individual teams and make everyone safe.