After decades of sales you would think these products would be tested for their ability to cause cancer, mutate dna and impair a womens ability to give birth.
https://www.pnas.org/content/115/5/1081
http://www.cidrap.umn.edu/news-perspective/2018/02/cdc-vaccine-panel-brings-back-flumist-2018-19-season
http://experimentalvaccines.org/2018/12/18/flumist-vaccine-not-tested-for-carcinogenic-or-mutagenic-response/