(Bloomberg) -- Johnson & Johnson sought regulatory clearance for its Covid-19 vaccine in the European Union, on track to become the fourth shot approved in Europe and the first that can be given as a single dose.

The European Medicines Agency said a decision could be possible by mid-March, capping a rolling review process that started on Dec. 1 and has allowed EMA to examine the data on the vaccine as it emerged. A European Commission approval could follow immediately thereafter, President Ursula von der Leyen said in a tweet.

Unlike the three shots already approved in Europe, J&J’s vaccine can be given in a single dose, an advantage as countries seek to speed up inoculations. The EU has ordered 200 million doses, though deliveries probably won’t start before early April, Von der Leyen warned earlier this month. J&J is sending some of of the vaccine it produces in Europe to the U.S. for the last stage of production, filling the shots into vials.

The bloc is struggling to speed up what has been a slow Covid vaccine rollout marked by public spats with one of its largest suppliers, AstraZeneca Plc, and a much lower vaccination rate than either the U.S. or the U.K. The EMA has approved the vaccine from AstraZeneca and its partner, the University of Oxford, as well as shots made by Moderna Inc. and by Pfizer Inc. with its German partner BioNTech SE.

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