Systemic autoantibodies and systemic autoimmune diseases could coexist with NMOSD. Considerable studies have found COVID-19 could provoke some autoimmune antibodies or autoimmune diseases. A study of 29 patients with severe COVID-19 who had no history of autoimmune diseases found that the prevalence of antinuclear antibody, β2-GPI, aCL, p-ANCA, and c-ANCA was 34.5%, 34.5%, 24.1%, 6.9%, and 6.9% respectively [5]. In another study, the prevalence of anti-Ro52 and anti-Ro60 antibodies was 20% and 25% in severe COVID-19 patients [6]. In some COVID-19 patients with neurological involvement, anti-caspr2, ganglioside GD1b, MOG, MuSK antibodies were also found. For the current case, autoimmune antibodies had not been tested before vaccination; thus, we could not determine whether she had a systemic autoimmune background in the past. In other words, it is not clear whether the vaccine just induces or directly causes NMOSD. Although multiple autoimmune antibodies were positive, it was not sufficient to diagnose any rheumatic disease at present.

This patient underwent serum cytokine tests twice after vaccination, and no elevations of inflammation markers were seen. Multiple autoimmune positive antibodies indicated that molecular mimicry may not be the major reason for the production of AQP4-IgG. It is possible that in the context of preexisting systemic immunity, the vaccine overactivated the immune system, exacerbated the production of AQP4-IgG, and eventually provoked NMOSD. As NMOSD is seriously harmful and curative, it is important to be aware of the NMOSD symptoms after vaccination. Cautions should also be given for those with preexisting systemic autoimmune abnormalities in vaccination for COVID-19.