The European Union is finalizing emergency legislation which could block exports of COVID-19 vaccines to the UK, and other countries with higher vaccination rates.
The move marks a sharp escalation in the EU's response to a floundering vaccination rollout at home, beset by delivery delays, supply issues and a third wave of the disease.
According to one EU official, the new regulation is aimed at making vaccine trade reciprocal and proportional, so the EU can no longer export more than it imports.
The EU has watched doses manufactured in its territory being used to advance vaccination campaigns elsewhere, like Israel and Britain, while its own programme has faltered much to the anger of its population.
The UK stands to lose the most by the new rules, as the biggest benefactor of EU exports thus far.
British Prime Minister Boris Johnson said Tuesday the UK did not believe in imposing vaccine blockades, and would work with EU authorities to ensure the delivery of vaccines it has ordered.
The new regulation will likely hit vaccine-maker AstraZeneca, which found itself in hot water with the EU after announcing a steep cut in supplies to the bloc in January, citing production problems.
It could also affect vaccines made by Johnson & Johnson, which has announced delays in its second-quarter supplies to the EU.