"The new recommendation is based partly on preliminary data that came out in late May, gathered during the 2015-16 flu season. It showed that the nasal vaccine had an efficacy of about 3 percent — in other words, it offered virtually no protection at all. By contrast, the injected vaccine, which uses an inactivated form of flu virus, is about 63 percent effective....The problem is that FluMist does not work against the H1N1 strain, which has been circulating more widely in recent years and causes the most serious disease in children. "he live version is not working as well as it needs to,” Dr. Flannery said. “Why that is, we don’t know.' "
They describe 4 ways that RNA is used clinically.
Zika Virus infect more than just neuronal precursors
Maybe such events are not as rare as previously thought!