The UK's health service is to suspend vaccination of people aged 49 and under, due to a significant shortfall in vaccine supplies.
In a letter sent out to vaccination project leaders, the NHS says it has been advised of a significant reduction in weekly supply from manufacturers from the week beginning 29 March.
It says the supply shortage is expected to last about four weeks, as a result of which "volumes for first doses will be significantly constrained".
The UK alone has followed a 12-week dosing interval for both the Pfizer and the AstraZeneca vaccines authorised in the country.