US regulators are expected to authorise a third booster shot of the Pfizer Inc /BioNTech Covid-19 vaccine for older and some high-risk Americans early this week in time for the government to roll them out by Friday as hoped.The Food and Drug Administration is expected to give the nod to the shots for at least this group in the days ahead of a meeting of advisers to the US Centers for Disease Control and Prevention scheduled for Wednesday afternoon, according to Reuters.

The CDC panel will discuss more precise recommendations for how the shots will be administered.

On Friday, an FDA advisory committee voted to recommend emergency authorisation of the additional Pfizer shots for Americans 65 and older and those at high risk of severe illness.