This paper in Thyroid describes relationships between covid infection and thyroid dysfunction. Though behind a paywall, I've got free access and have sent the paper in whole to Louise Roberts at TUK for anyone interested.
THYROTOXICOSIS IN PATIENTS WITH COVID-19: THE THYRCOV STUDY
Andrea Lania 1, Maria Teresa Sandri 2, Miriam Cellini 3, Marco Mirani 4, Elisabetta Lavezzi 5, Gherardo Mazziotti 6
PMID: 32698147 DOI: 10.1530/EJE-20-0335
It will be interesting to read this paper.
The way patients describe the after affects of having had covid infection (long covid) sound very similar to hypo thyroid symptoms. I've wondered if covid 19 affects the thyroid gland.
You can email me at louise.roberts@thyroiduk.org I also have a mailing list for things like this, so let me know if you would like to be added. 
Thank you again, Diogenes. I have been struck that I've twice been asked by the Zoe survey to take a covid test when reporting symptoms that, I have let them know, are present from time to time with Hashi's. It is important to hear that thyroid is in mind.
Thanks so much, I've been trying to find a way to access this, particularly interested in how they define 'thyrotoxicosis'.
Thankyou, Did they look at full TFT's or just TSH ? the abstract that tcpace linked to seems to show observations on TSH only.
There were a few FT4 results, on 7 patients, showing that they started off "hyperthyroid" but responding to hyper reducing drugs. No FT3 though, so we cannot say whether the high FT4's were due to a hyperthyroid (true) situation or a temporary inhibition of T4-T3 conversion (false). A pity because it would have cemented the situation properly.
Thankyou. Yes,what a shame , maybe the Italians also have difficulty getting their labs to test FT3. (If they even know what an FT3 is)
Still at least they're thinking about the possible connection , so i'll take it as a positive.
What is thyrotoxicosis?
The opposite of hypothyroidism. Too much not too little.
After reading the paper more closely, it seems that some patients with overt thyrotoxicosis had elevated FT4 but not FT3. This seems therefore to be a matter of suppressed conversion in these patients. Inflammation of the thyroid was noted in some cases, and it isn't clear what resulted from this. The overall findings indicate that patients with covid showed all kinds of responses and there doesn't seem to be a consistent thread running through it, except that thyroid function can be disturbed in either direction. The upshot is that covid is more likely to produce T4-toxicosis rather than FT3 as in true hyperthyroidism. In all, I think the findings indicate a form of nonthyroidal illness, with a thyroid true dysfunction sometimes accompanying it.
I `Guess all things considered, it would be a bit worrying if the thyroid system didn't react in some way to getting a nasty case of Covid. Maybe they should also look more closely at the ones whose thyroid didn't notice anything was occurring.
Thyroid Hormones and Cardiovascular Function and Diseases
Thyroid not functioning well 
Covid booster and subacute thyroiditis
TSH effect on Thyroid function. 
