Two rotavirus vaccines were suspected of causing a rare but serious side effect (that they actually caused it at higher rates is somewhat less clear). They were

Two rotavirus vaccines were suspected of causing a rare but serious side effect (that they actually caused it at higher rates is somewhat less clear). They were immediately pulled off the market, and replaced with a vaccine that doesn't cause said side effect - which has been vigilantly monitored with post-market studies ever since. A smattering of double-blind RCTs for you: https://clinicaltrials.gov/ct2/show/NCT00122681 https://clinicaltrials.gov/ct2/show/NCT00122681 (HPV) https://clinicaltrials.gov/ct2/show/NCT01266850 https://clinicaltrials.gov/ct2/show/NCT01266850 (Rotavirus) https://clinicaltrials.gov/ct2/show/NCT01171963 https://clinicaltrials.gov/ct2/show/NCT01171963 (also Rotavirus) You'll find them relatively easily for novel vaccines. In another post I mention unethical studies. Asking for new RCTs for existing vaccines used to prevent childhood disease is absurdly unethical, and would never pass muster at any self-respecting institutional review board. The best you'll get is comparisons between new formulations and existing vaccines, ala https://clinicaltrials.gov/ct2/show/NCT00861744 https://clinicaltrials.gov/ct2/show/NCT00861744 because there's no reason to put a swath of children at risk of preventable childhood diseases when we have working vaccines with very little evidence of serious side effects.