US FDA questions wisdom of relaxed vaccine dosing schedule

The US Food and Drug Administration has weighed in on the question of coronavirus vaccine dosing, as health experts and the general public alike discuss the best way to optimize limited supplies.

Two innovative mRNA-based vaccines for COVID-19 disease have been approved by regulators, including in the USA, and both require two doses, given several weeks apart.

In the UK, public health authorities have taken the unusual step of recommending that doctors deviate from the dosing schedule which was shown to be safe and effective in Phase III trials.