[DIYbio] How safe is lysed E.coli as an adjuvant?

Often in vaccine development, in addition to target antigens that you want to raise antibodies against, an adjuvant, something that stimulates the immune system like lipopolysaccharide, must be added in order to generate an adaptive immune response against the antigen. E.coli is covered with lipopolysaccharide, which reacts strongly to complement (antibacterial factors in blood), and so would be a good candidate for an adjuvant. This line of thinking leads to an "easy vaccine" where you express the antigen in E.coli and thermally lyse the cells, dilute them to some concentration in water for injection, and there you have your vaccine. In an outbreak like coronavirus, making vaccines like this would seem to be "low risk, high reward" in that nothing bad seems likely to come of it, but you could potentially immunize against this bad outbreak.