COVID Transmissions for 10-22-2020
A new definition for close contact
Good morning! It has been 340 days since the first documented human case of COVID-19.
I’m still trying to digest all the work that has been done about transmission on airplanes. However, there have been some notable news developments.
As usual, bolded terms are linked to the running newsletter glossary.
Keep the newsletter growing by sharing it! I love talking about science and explaining important concepts in human health, but I rely on all of you to grow the audience for this:
Now, let’s talk COVID.
CDC expands definition of a “close contact” for COVID-19
As reported in The Washington Post, the CDC has altered their definition of a close contact for COVID-19: https://www.washingtonpost.com/health/2020/10/21/coronavirus-close-contact-cdc/
The change is subtle. Instead of requiring 15 consecutive minutes of close proximity (less than 6 feet) to someone who is positive for SARS-CoV-2 infection, the guideline now indicates that a close contact is anyone with 15 total minutes of close-proximity contact to a positive patient within 24 hours.
This turns the guideline from one that looks for bouts of prolonged exposure into one that looks at cumulative exposure. This is probably a good change; transmission events occur by chance, and added exposure time increases the chance of transmission. Especially if there is some minimal infectious dose; you might be exposed to a small amount in the first minute, but it make take 14 more minutes of exposure to reach the minimal infectious dose.
The boundary of 24 hours is probably arbitrary, but it’s a good kind of arbitrary. Virus infections usually take hours to set in. By choosing 24 hours, the boundary is set at a length that is much longer than the typical kinetics of an early virus infection.
Mouthwash won’t save you from COVID-19
Apparently, some misunderstanding of a recent study has led people to believe that COVID-19 might be prevented by using mouthwash. This study indicated that under laboratory conditions, mouthwash could inactivate human coronaviruses that cause the common cold. This is interesting, but it does not indicate that mouthwash will offer special protection against any particular virus, and especially not against SARS-CoV-2, which was not studied.
While there may be good reasons to use mouthwash, I am not a dentistry expert so I can’t really comment. On the other hand, I can be certain that mouthwash will do very little to affect a virus infection that extends into the lungs.
While the use of mouthwash may sterilize the mouth temporarily, there is a tremendous amount of virus being produced in the lungs in even a rather mild infection. Whatever the mouthwash may do, the virus will soon repopulate the upper respiratory tract.
See the New York Times on this: https://www.nytimes.com/2020/10/21/health/covid-mouthwash.html
What am I doing to cope with the pandemic? This:
Braising
Our CSA has been really into giving us greens that are best braised, so I figured I’d lean into this cooking technique, even though it’s not really a go-to for me. For those not familiar, braising is a technique in which the food being cooked is seared or fried quickly, and then finished by long-simmering in a liquid. It produces really tender meats, turns chewy vegetables soft, and also has a habit of creating excellent gravies.
Last night I made some braised chicken with onions and braising greens. I seasoned these early on with a mixture of things I’m fond of using on chicken, but I think essentially whatever you like to season chicken with could be substituted.
After frying/searing all of these items in the pan, I added a little liquid smoke, some apple cider vinegar, and some water, then covered the pan and put it in the oven at 350F for about 45 minutes. Towards the end, I uncovered it for about 10 minutes.
Image is 4 chicken thighs on a bed of greens in a metal pan. This was after the initial fry/sear.
Image is the same 4 chicken thighs, in the same pan, with the same greens, after some time spent in the oven.
Image is the finished dish, plated. You can see the greens are cooked but still bright, while the chicken has some nice color on it (though truth be told I could have gotten better color with a harder sear).
Join the conversation, and what you say will impact what I talk about in the next issue.
Also, let me know any other thoughts you might have about the newsletter. I’d like to make sure you’re getting what you want out of this.
This newsletter will contain mistakes. When you find them, tell me about them so that I can fix them. I would rather this newsletter be correct than protect my ego.
Though I can’t correct the emailed version after it has been sent, I do update the online post of the newsletter every time a mistake is brought to my attention.
No corrections since last issue.
Thanks for reading, everyone!
See you all next time.
Always,
JS
Regarding the mouthwash, I agree that once the virus invades the LRT, it is useless. However many times COViD starts as URTI and it is localized to the nasopharyngeal mucosal epithelia. During this time, gargling could reduce viral load in the mouth thus reducing transmission risk and symptoms. Please check ELVIS trial out of university of Edinburgh. Same team is running similar trial for COVID. While I agree it won’t cure it, it might offer benefits when applied early in the infection cycle.