CDC requiring negative COVID-19 test for international flights

INDIANAPOLIS (WISH) — The coronavirus could impact your travel plans, if you’re planning to fly, that is.

There’s the possibility that passengers can spread the coronavirus in flight even after testing negative prior to boarding. 

News 8 spoke with Dr. Cole Beeler, infectious disease physician at IU Health, to explain.

Gillis: The Centers for Disease Control and Prevention just came out with a statement requiring that people need to test negative for the coronavirus before they board a flight. And this comes after people boarded a flight and four passengers during an 18-hour international flight seemed to have gotten the virus in transit. How is it possible they could have contracted the virus on the plane?

Beeler: What it seems like with this report is there was one infected person on the plane, even though they had a negative test. But negative tests aren’t perfect. They might tell you you are not infectious at one point in time. They don’t tell you what’s actually happening to you on the plane as far as infectivity. So, I think that one infected person was able to infect the other people around them and it was following a lot of the same patterns that we’re used to seeing is the people who are closest have a higher probability of getting it. 

Gillis: What does this say about the environment of a plane? I read that planes actually have good ventilation. 

Beeler: International air travel is problematic for COVID-19 in general. I don’t necessarily associate it with the plane as much as I do with the airports and being around clusters of people. But even the plane which puts you in close proximity to a lot of people who may or may not be masking depending on what type of flight you’re on is problematic and does potentially put you at risk for contracting COVID-19. 

Gillis: Going back to what you said about the person having the coronavirus, but the reading was a false negative…we know that very early in time there’s not enough of the virus present so that’s why we get these false negatives. So, how is it that the CDC’s new guideline is going to help? Because in many cases we just don’t know yet. 

Beeler: Yeah. I think this case highlights that even with the best protocols there’s still going to be bleed over and transmissions that happen because unfortunately with this virus you shed and are infectious when you’re not symptomatic and our diagnostics don’t work as well except right before you’re symptomatic or right after you’re symptomatic and the sensitivity of our tests any other time might not be optimal to making sure that we’re able to 100% exclude that someone may or may not be infected. 

Now, I would say that any sort of policy around testing is better than a policy of not testing so it is a step I think in the right direction around these prolonged flights where people are a risk. But there are still going to be cases where transmission occurs despite the best intentions. 

Gillis: Our testing really hasn’t gotten much better from the beginning and I’m just wondering what your thoughts are about that.

Beeler: I think we have the best technology there is to really diagnose any microbial infection, which is PCR and is available for detecting this which is usually very sensitive. Unfortunately, the way that this virus interacts with the human body is that it can ramp up its productivity…it’s production of the virus very quickly and it can also decrease it very quickly.

In addition to that there are a lot of different types of tests for the coronavirus and some are better than others, so some people might get a less good test like what I would consider an antigen test. It’s just not as reliable. It’s just not as sensitive and that might provide some false reassurance when you get on the plane if you are infectious. So there’s a lot that goes into it. It’s not just the interaction between the virus and the human, but the test that’s being run, what the cutoffs are that you’re using, etc. 

Gillis: If we’re now looking at planes, do you think these same policies will be implemented with trains, buses or public transportation? Is that something we can anticipate moving forward?

Beeler: Yes. I would consider them really all the same. You’re clustered together. There are close seating arrangements with maybe questionable ventilation. I would say the main difference between most bus and most train rides is that they are generally shorter. But for longer bus rides and train rides that’s a higher risk. In general, you get infected with coronavirus by a function of time, proximity and density of the virus that’s around you. The longer you are closer to someone who has coronavirus and there is poor ventilation or less opportunity for clearance of the virus that’s in the air the higher the probability that you’re going to be infected. 

And that spreads to all sorts of corollaries and situations that aren’t necessarily travel related, but tightly packed restaurants, bars, gym–places that people aren’t able to de-densify and avoid as much. The longer you’re in those settings the higher the risk you might be for infection.

Gillis: Would you recommend sticking to necessary travel only? I know that was a big thing early on when we first had the coronavirus.

Beeler: I don’t think we’re in a setting right now across the world, especially in Indiana and the United States, where any sort of optional travel makes a whole lot of sense to me. If it’s something you elect to do it’s putting you at risk and it’s potentially putting people around you at risk because you don’t know who you’re going to spread the virus to. 

So, I honestly think it’s kind of a bad idea right now just because the virus is everywhere. It’s spreading very silently, but people are still getting very sick and dying from it. So, we have to just maintain precaution when doing any activity outside of our normal sphere of practice. 

Gillis: Scientists are saying they are looking into researching this more. What would that look like?

Beeler: I think there are a ton of questions that need to be asked related to COVID-19. It spreads in these close quarters of airplanes. We still don’t know a whole lot and each individual is a little bit different as it relates to when the virus decides to shed after infection, how long infectivity goes on, what the infectious dose is of the virus. So, how many individual viruses do you need to get into your lungs to contract and maintain infection.

All of this stuff would be helpful to understand how to mitigate risk to a certain extent. But unfortunately, the coronavirus has created a lot of speed bumps along the way with trying to help us understand exactly how we can build rules around protecting every single individual. It tends to break a lot of rules 

Gillis: Last 30 seconds. Anything else you’d like to add?

Beeler: From my perspective, the main thing is just being very cautious with any sort of extra activities that you’re thinking about doing right now. COVID-19 is getting worse in Indiana. It is still a very serious infection and we are a long way off to getting the population vaccinated in time to actually make a dent in this. We’re in for a few rough months. Again, avoid unnecessary travel and gatherings with large groups of people. 

News 8’s medical reporter, Dr. Mary Elizabeth Gillis, D.Ed., is a classically trained medical physiologist and biobehavioral research scientist. She has been a health, medical and science reporter for over 5 years. Her work has been featured in national media outlets. You can follow her on Facebook @DrMaryGillis.