Here is the latest on the subject:
- A Russian group found that increases in serum copper as well as Cu/Zn serum ratios correlated with covid-19 severity 
- A Chinese group looked at urinary trace element Levels in 210 urinary specimens from the 138 severe and non-severe patients with COVID-19.  The reference range for Cu is [4.00–21.42] μg/L. Urine Cu was 15.84 (10.48–20.68) in mid Covid cases and 32.14 (17.22–75.43) in severe Covid cases. Urine Cu was significantly elevated in severe Covid (p <0.001).  When the trace elements in the urine were adjusted for creatinine, even more copper was being lost in the urine in severe Covid-19 cases. Accounting for glomerular filtration, Cu amounts were reported relative to creatinine.  The reference range is [4.39–13.37] μg/g creatinine. Average Cu (and range) in mid versus severe Covid were 15.55 (12.41–20.45) and 77.71 (32.04–248.28) μg/g creatine, respectively. (p < 0.001). Urinary creatinine-adjusted copper of ≥25.57 μg/g and ≥99.32 μg/g were associated with significantly increased risk of severe illness and fatal outcome in COVID-19, respectively.
- A German group found that serum copper was higher in patients who were released from the hospital versus those that died.  No change was seen in ceruloplasmin. A caveat is that the ceruloplasmin activity was not measured.
The German  and Russian  groups reported different control ranges for serum copper. The Chinese report suggests that large amounts of copper may be lost in the urine in severe Covid.  Could copper loading of ceruloplasmin be compromised in severe Covid?
- Skalny, A. V., Timashev, P. S., Aschner, M., Aaseth, J., Chernova, L. N., Belyaev, V. E., Grabeklis, A. R., Notova, S. V., Lobinski, R., Tsatsakis, A., Svistunov, A. A., Fomin, V. V., Tinkov, A. A., & Glybochko, P. V. (2021). Serum Zinc, Copper, and Other Biometals Are Associated with COVID-19 Severity Markers. Metabolites, 11(4), 244. PMC free article
- Zeng, H. L., Zhang, B., Wang, X., Yang, Q., & Cheng, L. (2021). Urinary trace elements in association with disease severity and outcome in patients with COVID-19. Environmental research, 194, 110670. PMC free article
- Hackler J, Heller RA, Sun Q, Schwarzer M, Diegmann J, Bachmann M, Moghaddam A, Schomburg L. Relation of Serum Copper Status to Survival in COVID-19. Nutrients. 2021 May 31;13(6):1898. free article