The UK’s Medicines and Healthcare products Regulatory Agency (MHRA) has announced that, though placebo-controlled disease endpoint trials are the gold standard for authorising vaccines, well-justified and appropriately designed immuno-bridging studies are an acceptable approach for authorising COVID-19 vaccines.
Immuno-bridging studies are controlled trials, leveraging placebo or other controls and correlates of protection such as humoral and/or cellular immune parameters to establish whether an intervention is effective.