Pharmaceutical company AstraZeneca has agreed to supply 9 million additional doses of its coronavirus vaccine to the European Union during the first quarter.
The new target of 40 million doses by the end of March is still only half what the British-Swedish company had originally aimed for before announcing a shortfall due to production problems.
The issue triggered a spat between AstraZeneca and the EU last week.
European Commission President Ursula von der Leyen said after a call with seven vaccine makers on Sunday AstraZeneca will also begin deliveries one week sooner than scheduled and expand its manufacturing capacity in Europe.
"Step forward on vaccines," tweeted Von der Leyen, who has come under intense pressure over the European Commission's handling of the vaccine orders in recent days.
The EU is far behind Britain and the United States in getting its population of 450 million vaccinated against the virus.
The slow rollout has been blamed on a range of national problems as well as slower authorisation of the vaccines and an initial shortage of supply.
AstraZeneca's announcement last week it would initially supply only 31 million doses to the EU's 27 member states due to production problems set off a fierce dispute, with officials in Brussels saying they feared the company was treating the bloc unfairly compared to other customers, such as the United Kingdom.
On Friday, hours after regulators authorised the vaccine for use across the EU, the commission said it was tightening rules on exports of coronavirus vaccines, sparking an angry response from Britain.
The commission has since made clear the new measure will not limit vaccine shipments produced in the 27-nation bloc to Northern Ireland, a UK territory guaranteed unhindered cross-border access to the Republic of Ireland under the post-Brexit deal between Britain and the EU.
EU member states praised the bloc's executive branch last year for signing numerous deals with vaccine makers, saying the joint purchase using the combined market weight of the entire bloc had ensured a fair distribution for all 27 countries at good prices.
Since then the mood among many EU citizens toward Brussels has soured, as countries outside the bloc speed ahead in the race to vaccinate their populations.
The British government hasn't been shy about promoting its relative vaccine success, which has helped distract from the fact the country remains top of the table for deaths in Europe.
Official figures show 598,389 shots were administered across the UK on Saturday, more than six times the number that Germany managed Friday, the last day for which figures were available.
Germany has so far given at least one dose to 2.2 per cent of its population. Britain has done the same for 13.2 per cent of citizens.
In response, Chancellor Angela Merkel has summoned state governors Monday to discuss what German media are describing as a "vaccination debacle".
Von der Leyen, who was Germany's defence minister before taking the Brussels post Brussels, insisted the EU had "made good progress".
"Of course we've currently got a difficult phase," she told German public broadcaster ZDF but added that in the second quarter more vaccine would become available as regulators approve additional formulas and further production capacity goes online.
Australian Associated Press