Serious adverse events observed in pre-licensure trials of Gardasil-9 cast doubts on HPV vaccine safety, but the trial investigators described the adverse events as not vaccine-related.
Vaccine-related serious adverse events might have been under-recognized in the pivotal HPV vaccine randomized trial
Martínez-Lavín M. Vaccine-related serious adverse events might have been under-recognized in the pivotal HPV vaccine randomized trial [Letter]. Clinical Rheumatology 2017;36(4):975.
The largest pre-licensure trial of the Gardasil-9 vaccine—which compared Gardasil-9 against Gardasil rather than against an inert placebo—showed that Gardasil-9 had significantly more serious adverse events than Gardasil (3.3% versus 2.6%, p=0.01). However, the trial investigators judged that 0% of the serious adverse events in both groups were vaccine-related. Gardasil-9 has “more than double [the] HPV virus-like particles and aluminum adjuvant” as Gardasil. The under-recognition of serious adverse events associated with Gardasil-9 “casts further doubt on HPV vaccine safety.”