From what I read it is unclear whether a vaccine administered nasally would produce the blood antibodies detected by tests.
From the paper:
One challenge for intranasal vaccines is verifying efficacy. Many published reports show that nasally delivered vaccines have high efficacy for prevention of infection, typically equivalent or superior to injected vaccines for this most important measure. However, efficacy is not as easily measured or predicted by traditional measures, such as anti-virus or anti-epitope antibody titer (e.g. as measured by ELISA) in serum. This is in part because blood is more quantifiable than mucosal secretions, and in part because the primary means of conferring immunity is through mucosal stimulation and response.