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#THREAD: COVID-19 could be a double whammy for older people -- they're more likely to die from it and they might be less likely to respond to a vaccine. This might be due to " #immunosenescence" and " #inflammaging", as I describe in my latest story: https://www.nationalgeographic.com/science/2020/07/why-those-most-risk-coronavirus-least-likely-respond-to-vaccine-cvd/
Surprise! If you are reading this tweet and past puberty, your thymus gland -- which harbors the T cells that help train the body to make protective antibodies against new viruses (and respond to vaccines) -- is already shrinking: https://www.nationalgeographic.com/science/2020/07/why-those-most-risk-coronavirus-least-likely-respond-to-vaccine-cvd/
Almost a century ago, Edith Boyd helped confirm that the thymus shrinks with age. Boyd was an anatomist who combed through data from 10,000 autopsies collected at the University of Minnesota and compared them to similar findings from European scientists: https://www.nationalgeographic.com/science/2020/07/why-those-most-risk-coronavirus-least-likely-respond-to-vaccine-cvd/
Weirdly, it was *30 years later* when folks actually figured out that the thymus made T cells -- it was the last organ in the body to have its function discovered. The organ is located right below your neckline between your lungs.
Boyd's research was part of the inspiration for gerontologist Roy Walford, who came up with the term ' #immunosenescence' to describe the dysfunctioning of the immune system as we age. 'Senescence' traces back to Latin senex, meaning "old".
(Sidebar: Walford's storied life also included using casino winnings to pay for medical school, working as the physician on the Biosphere 2 and conducting key animal studies showing that caloric restriction increases longevity.)
In the year 2000, scientists coined the term #inflammaging â it describes how the immune systems of older people have the hallmarks of inflammation. That inflammatory "noise" could make it harder for the body to "hear" a virus or vaccine: https://www.nationalgeographic.com/science/2020/07/why-those-most-risk-coronavirus-least-likely-respond-to-vaccine-cvd/
To make matters worse, some studies say that older people's immune systems are preoccupied with fighting viruses that stay inside us lifelong, like CMV. Around 20% of some older people's immune systems are preoccupied with CMV.
Scientists really want to study how older immune systems struggle with vaccines, BUT getting old mice is hard. One researcher I spoke with said his supplier was out of stock and won't have aged mice until... January 2021. 
Does a lifetime of exposure to other coronaviruses help older people? The science is VERY iffy. It is highly speculative but antibodies that are cross-reactive might glom onto SARS-CoV-2 and perhaps prevent the body from making better antibodies. (
only one hypothesis)
only one hypothesis)
Here's the rub: Influenza and shingles shots for the elderly could be seen as boosters. As Martin Friede of the @WHO told me: âFor COVID-19 [vaccine], we are likely going to have to prime the population against something that theyâve never seen before.â https://www.nationalgeographic.com/science/2020/07/why-those-most-risk-coronavirus-least-likely-respond-to-vaccine-cvd/
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) and want to read my future articles on #COVID19 and other health discoveries, you can sign up for my free email alerts here: https://roxanne.substack.com/p/coming-soon
