COVID Transmissions for 8-21-2020
Greetings from an undisclosed location in my apartment.
It has been 278 days since the first documented human case of COVID-19.
Housekeeping note:
I’ll continue the in-depth on virus origins next week. For now, headlines going into the weekend. Enjoy yours; these summer weekends are precious.
Glossary terms are bolded words with links 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.
Germinal centers and immune memory
A paper just accepted in Cell reports an absence of immune structures known as “germinal centers” in the lymphatic system in patients who died of severe COVID-19. Germinal centers are places where cells of the immune system interact with and educate each other and are thought to be part of the process of formation of immune memory.
I have seen at least one press article referring to this as potential evidence that immune memory may be short-lived because cytokine responses may interfere with the formation of immune memory. I think this is an exaggeration of what the results say, and I think that it goes far beyond the actual study. This is a study of tissue from people who died of the disease. People who die, definitionally, do not have immune systems. Germinal centers are something that, as I understand them, form during a successful immune response. Dying from the virus does not strike me as representative of a successful immune response and I do not think that we should generalize from this population to those who do recover. I believe the authors overstep substantially when they make the statement “a mechanistic explanation for the limited durability of antibody responses in coronavirus infections and suggest that achieving herd immunity through natural infection may be difficult.”
Clearly, there are different types of immune responses to COVID-19, and a small number of people mount an inappropriate and unsuccessful immune response. This paper demonstrates that, and to my mind, only that.
You can read the paper here: https://www.cell.com/cell/pdf/S0092-8674(20)31067-9.pdf?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867420310679%3Fshowall%3Dtrue
Disease and viral load in children
There is a new paper in the Journal of Pediatrics that nicely establishes that children can get COVID-19, and that children carry the virus with the potential to spread it. In fact, the infected children in this study had viral loads significantly higher than those of adults with severe disease. This does not bode well for school reopenings.
You can read the paper here: https://www.jpeds.com/article/S0022-3476(20)31023-4/fulltext
More approachable coverage at CIDRAP, here: https://www.cidrap.umn.edu/news-perspective/2020/08/kids-covid-have-more-viral-rna-their-airways-adults-do
Case counts on the rise in Western Europe
Spain, France, and Germany have recently reported their highest daily new case counts since they began to ease lockdowns, also a CIDRAP story: https://www.cidrap.umn.edu/news-perspective/2020/08/covid-19-cases-climb-higher-european-countries
These are resulting from small, localized outbreaks that appear to be driven by risky behavior particularly among young people. However, the numbers we are seeing in these countries are still quite low by comparison to, say, the US or other countries where spread is uncontrolled, keep in mind.
COVID-19 likely not transmitted through breast milk
There are viruses that can pass from parent to child through breast milk. HIV is a notable example.
So, it is reassuring that a research letter in JAMA shows that it is unlikely for this to be a means of transmission for SARS-CoV-2: https://jamanetwork.com/journals/jama/fullarticle/2769825
Out of 64 milk samples collected from 18 women, only one was virus RNA positive, and none were positive for infectious virus.
These numbers are small but they provide some reassurance that breast milk itself is unlikely to transmit the virus. That said, breastfeeding involves close contact that can otherwise spread the virus, so any breastfeeding parent who is infected with SARS-CoV-2 should consult their doctor for advice on how to minimize exposure of their infant.
What am I doing to cope with the pandemic? This:
Watching
Netflix has a new documentary series called High Score on the history of video games, and we’ve been enjoying that.
Cooking
I’ve been working on mastering egg rolls, because…you guessed it…cabbage is a common filling for them.
I think I’ve gotten everything right with them, but I’m not sure there’s enough space in the newsletter to walk through the procedure. I’ll share a photo, perhaps, in a future issue.
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.
See you all next time. Have a great weekend!
Always,
JS