# Transit use and flu/pneumonia



## MARC Rider (Dec 13, 2020)

Looks like people who are worried that reliance on public transportation increases the risk of catching disease can rest a little easier:

Public transportation and transmission of viral respiratory disease: Evidence from influenza deaths in 121 cities in the United States (plos.org)

Study explores link between public transportation and spread of seasonal flu - The Washington Post

The study was done with pre-Covid data, so it focused on the flu and pneumonia. However, the finding may also apply to Covid as well.

As always, though, be safe, keep the masks on, and keep your distance.


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## AmtrakBlue (Dec 13, 2020)

I'm taking Amtrak to my audiology appts and then using the metro in Baltimore. I feel that the metro is possibly safer than a taxi. 

BTW, how well does the metro run on days after 5-8 inches of snow? My activation is Thursday, if it doesn't get rescheduled if I tested positive for COVID (did the test yesterday) or due to the snow.


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## bms (Dec 13, 2020)

Public transportation shouldn't be dangerous, but our Cleveland RTA does not enforce its mask mandate. I don't drive either, so I take Uber to and from work every day. I noticed that drivers who don't wear the mask properly always have a rating of 4.6, 4.7, or 4.8, so I just cancel the ride until I get assigned someone who either has a 4.9 or 5.0, or who I know from previous trips. There's basically no chance that a 4.9 or 5.0 rated driver would be unsafe because they would have been downvoted previously.


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## jis (Dec 14, 2020)

I think it would be useful if someone did a real apples to apples comparison study between a group traveling by transit and a control group traveling by single use private cars or something like that, so as to get all the speculative explanatory stuff as to how representative the proxies that are used in these studies and meta studies are.


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## MARC Rider (Dec 14, 2020)

jis said:


> I think it would be useful if someone did a real apples to apples comparison study between a group traveling by transit and a control group traveling by single use private cars or something like that, so as to get all the speculative explanatory stuff as to how representative the proxies that are used in these studies and meta studies are.


In the earth science and environmental field, these sort of observational studies are about the only way you can study anything, as it's really hard to do experiments by, say pumping one planet's atmosphere full of greenhouse gases and see what it does to global climate, and take a control planet of similar characteristics and refrain from emitting greenhouse gases.  The only geological "experiment" I can recall from my schooling is when someone was able to set off earthquakes by pumping oil fields and observing that the earthquakes stopped when they stopped pumping oil.

In order to fully explain the observations noted by this paper, you'd have to run not just one "apple to apples" comparison study, you'd probably have to run a bunch of them, as each experimental group would have it's own peculiarities. It would probably be better to do more observational studies to establish that the data set is representative, and that you were able to evaluate the possibility of interference from other factors. I believe these authors did account for a large number of explanatory variables related to age, socioeconomic status, health care infrastructure, etc. among the different cities. Perhaps there are others that need to be considered.


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## hlcteacher (Dec 14, 2020)

i live in cleveland also; my last ride on rta was in march before the mask mandate but people seemed to be social distancing; a gentleman in the front of the bus started to cough and sneeze, he did not seem to have tissue and as much as i regret it, i was not going close enough to him to hand him some...the third time he did it, the driver pulled over and opened the door to "air out the bus"...the fourth time the driver told him he had to get off at the next stop (guess it was his stop because he went quietly)...i miss my weekly travels around the county and when i see a bus it appears to be pretty empty, but i can wait until it is safer (and rta will probably have cut most of the lines and doubled the fare)


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## MARC Rider (Dec 14, 2020)

MARC Rider said:


> The only geological "experiment" I can recall from my schooling is when someone was able to set off earthquakes by pumping oil fields and observing that the earthquakes stopped when they stopped pumping oil.



Actually, there are more geological "experiments" that can be done. There are geochemists who melt rocks under controlled conditions and then observe the order of crystallization of minerals from rock melts of varying chemical composition. I never got involved in that stuff, because I specialized pretty early into doing the environmental stuff, working at atmospheric pressures and typical surface temperatures. Nearly all of my scientific work involved observational analyses. Nobody in their right mind was going to let us dump some toxic waste on one field, leave another field alone, and then see the difference in the ground water quality between the two fields. All we could do would be to sample the contaminated site and then try to figure out what was going on:

Assessment of Natural Attenuation of Contamination
from Three Source Areas in the East Management
Unit, Dover Air Force Base, Kent County,
Delaware


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## jis (Dec 14, 2020)

MARC Rider said:


> In the earth science and environmental field, these sort of observational studies are about the only way you can study anything, as it's really hard to do experiments by, say pumping one planet's atmosphere full of greenhouse gases and see what it does to global climate, and take a control planet of similar characteristics and refrain from emitting greenhouse gases.  The only geological "experiment" I can recall from my schooling is when someone was able to set off earthquakes by pumping oil fields and observing that the earthquakes stopped when they stopped pumping oil.
> 
> In order to fully explain the observations noted by this paper, you'd have to run not just one "apple to apples" comparison study, you'd probably have to run a bunch of them, as each experimental group would have it's own peculiarities. It would probably be better to do more observational studies to establish that the data set is representative, and that you were able to evaluate the possibility of interference from other factors. I believe these authors did account for a large number of explanatory variables related to age, socioeconomic status, health care infrastructure, etc. among the different cities. Perhaps there are others that need to be considered.


I had something similar to clinical trial in mind without which no self-respecting medical practitioner would recommend the use of a procedure to definitively address a medical issue. This is something fesible in this case and all the hoo-haa about geological experiments is just red herring IMHO.  Also I am not denigrating what has been done at all. All that I said it would be nice to additional stuff to defnitively cover more bases, which is quite similar to clinical trials and quite feasible.


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## MARC Rider (Dec 14, 2020)

jis said:


> I had something similar to clinical trial in mind without which no self-respecting medical practitioner would recommend the use of a procedure to definitively address a medical issue. This is something fesible in this case and all the hoo-haa about geological experiments is just red herring IMHO.  Also I am not denigrating what has been done at all. All that I said it would be nice to additional stuff to definitively cover more bases, which is quite similar to clinical trials and quite feasible.


A "clinical trial" type study is necessary for evaluating the effectiveness of some sort of technology. However, it's not necessary for evaluating general policy. I'm not sure if anyone ever conducted a "clinical trial" on whether smoking was harmful to health, in fact, I would think that doing one would be unethical. Medical researchers came to understand the risks of smoking through observational studies. I know in the environmental world, most policy decisions are made on the basis of observational studies. 

The results of this flu/pneumonia - transit study seem to indicate that there's probably no need to dismantle public transportation as a strategy to reduce transmission of viral diseases. That's an important policy question, as those who are opposed to public transportation might argue that transit is a health hazard, and everyone should travel in private vehicles. This study suggests that the "health hazard" argument is not really very strong.

In order to do the kind of study you suggest, the database would have to have information about a very large number of people, and their medical history and whether or not they were transit raiders (also correcting for how far they rode and what mode of transit, etc.) I don't think that sort of database exists. The guys who did this study just used existing health statistics. That's another thing about research to inform policy, is that the policymakers have to make a decision now, and don't have the time or funding to do a study that will show things definitively.


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