22 percent of patients hospitalized for COVID-19 had experienced hair loss, which typically happens after stress, a shock, or a traumatic event. [Lancet 2021;397:220-232]
Another study showed that patients who had a COVID-19 infection were nearly four times as likely to have hair loss (hazard ratio [HR], 3.99) compared with those who were not infected. [Nat Med 2022;doi.org/10.1038/s41591-022-w] ... not a stretch to at least investigate the possibility of spike derived vaccine to have similar effects
https://www.sciencedirect.com/science/article/pii/S0140673620326568
https://www.nature.com/articles/s41591-022-01909-w