With students not being required to wear masks in schools, the state of Georgia should expect to see the number of coronavirus cases rising in coming weeks, according to an epidemiologist at Emory University.

"The question for me right now is: How much?" said Alicia Kraay, an infectious disease epidemiologist at Emory who is working on a study about the effectiveness of cleaning and disinfection in regards to COVID-19.

The reopening of schools in Georgia has come under the national spotlight after photographs of crowded hallways at North Paulding High and other pictures of students not socially distancing in Cherokee County went viral last week.

"When I see those pictures," Kraay said, "I realize that we really have an uphill battle."

North Paulding High shut down temporarily for a deep cleaning this week after a surge of COVID-19 cases was reported. Nearly 20 schools in Cherokee County have reported coronavirus cases, including Etowah High School, which announced Tuesday it was closing for several weeks.

Kraay said she expects to hear similar stories as more and more schools reopen to in-person classes.

“It’s going to be hard to avoid outbreaks in schools in general, especially for the older age groups where students are moving between classes," she said.

In a wide-ranging interview, Kraay spoke to GPB News about everything from the effectiveness of deep cleaning to the controversy over wearing masks. "I really wish everyone would wear a mask," she said.

The transcript of the interview has been edited for length and clarity.

Question: What does the science say about deep cleaning? Is deep cleaning just a feel-good measure if you’re not following other recommendations of public health officials?

Kraay: There are a couple different components to your question. The first question: Does cleaning actually get COVID off the surfaces? The answer to that is yes. There have been a number of studies that have shown that COVID is sensitive to a variety of different cleaning agents and, if you clean a surface, it is not going to be there afterwards.

But the implications of that are a little bit more complicated. The virus can be spread in a number of different ways and surfaces is just one of those.

If you had a room where someone had been sick in for a prolonged period of time, you’re going to have pathogens on the surface. If someone walks into that room a few hours later, it’s definitely possible they could get infected just from touching surfaces. So far as we know, that’s what the science seems to suggest.

Surfaces could spread COVID, and cleaning surfaces could prevent that.

However, there are other things in play here. People could come back to school, and they could already be infected and not have symptoms yet because there is an incubation period.

Even if we remove all pathogens from the environment, that’s not to say people aren’t going to be getting exposed when they come back to school.

That’s the brief answer: Cleaning does work and cleaning can help prevent some transmission, but there’s more than one way people can get infected.

The other thing to keep in mind: We also know that pathogens on surfaces for most the time will be gone within about three days. So, the shutdown by itself – just closing schools for several days, especially if it were three or more days long, probably most of the pathogens on surfaces would be gone already, even if they hadn’t done the actual cleaning.

Question: Are you in touch with schools or, if schools were to reach out to you, what would your takeaways be for them?

Kraay: We’re not actively in touch with any schools, but we are in contact with the CDC. I know the CDC has been in contact with different schools that are trying to get advice.

What we told them is COVID is predominantly spread through aerosols and droplets and things like that. So, it’s hard. If you’re in the same room as someone with COVID and they coughed on you and they shook your hand and they coughed on the table, it is really hard to tell how you got infected because you could’ve gotten infected by all three of those things.

But based on what we told the CDC, it’s going to be hard to avoid outbreaks in schools in general, especially for the older age groups where students are moving between classes and people, it seems, are more likely to transmit in those older groups.

What our work suggests is the most important thing is that if we can reduce the amount of pathogens shed on surfaces by wearing masks – which I know is not very popular – we can do that. That’s going to make a big difference.

If we can combine students wearing masks with regular cleaning particularly on surfaces like stainless steel where we know pathogens survive the longest, that’s going to be the most effective way we can limit transmission in schools.

What the CDC has already recommended for elementary schools and lower grade levels, if you have smaller classrooms and those classrooms don’t interact with each other that should help, too, because it lowers the probability.

It also makes it more likely that if there is a case, you can really isolate the people who have been in contact with that case. Those things are a lot harder to implement in a high school because people do have to change classes.

Question:  What has your reaction been as a scientist to seeing these viral photos of crowded halls to tons of students shoulder to shoulder?

Kraay: It highlights how difficult this is going to be – to really implement.

One of the questions that I’ve had: Even if we tell all students to wear masks, how much are people going to comply with that?

The other question is: If we tell people to socially distance, how possible is that when you have a packed building?

When I see those pictures, I realize that we really have an uphill battle, and it looks like, as of right now, what we need to do to minimize risk is probably not happening.

I’m not sure what’s going to happen in the coming weeks and months, but I guess we’ll have to see how this evolves. I know that in some of the school systems in North Carolina they have divided children and they’ve been able to reduce the number of people who are in physically in schools to about 25% of total capacity. I think that has a lot of promise.

But when I see those pictures, I know that what is being implemented right now is probably not going to be enough because of crowding.

Question: Are you fearful about what might be coming in the next three weeks or what word would you use?

Kraay: I don’t know if fearful is the right word. I think that the data on how children, particularly younger children, are infected is still ambiguous. I think, in general, people in the scientific community are expecting there to be increases in transmission.

But the question still is: How much?

I still have that question and all of the other people I am interacting with have the same question.

This is going to depend a great deal on community-level incidents, and it’s going to depend on how high the burden is in these different places. So, places where the outbreak has largely been brought under control I’m not as worried about. But places where it has not, I am more concerned.

I don’t know to what degree people are going to comply with recommendations. I don’t know what fraction of kids in schools are going to wear masks. Because of that, I’m not sure how much it’s going to spread. It’s kind of a wait-and-see.

But I’m expecting an increase in cases. The question for me right now is how much.

Question: Final thoughts on the mask controversy?

Kraay: I know that masks are complicated for a lot of people in terms of the compliance. I understand why people are hesitant to mandate it, but at the same time I really wish, as a scientist, that these things could be ordered.

I also do wish I could trust the American people to follow through on this. Because in large part, people’s unwillingness to comply with early scientific recommendations is the reason why incidents are so high right now. Which is also why it’s going to be harder to reopen schools.

I guess my answer is complicated. I understand the governor’s position; at the same time, I really wish everyone would wear a mask, as a scientist, based on what I know.