The looming third wave of coronavirus infections and Europe's struggle to mount a vaccination drive will dominate Thursday's EU video summit, despite a welcome guest appearance by Joe Biden.
The new US president will address the 27 EU leaders by video link in the evening as Washington and Brussels put on a show of mending ties after the dramatic diplomatic battles of the Donald Trump years.
But his intervention will only be a brief respite from the main matter at hand: How to outpace the resurgent epidemic when drug deliveries came up short and vaccination campaigns started slowly?
Host Charles Michel, the president of the leaders' European Council, had hoped to hold a substantive face-to-face summit, but was forced to accept a stripped down video conference as EU members reinstated lockdown measures.
The Europeans are angry that UK-based pharma giant AstraZeneca has failed to meet its vaccine delivery promises to the EU while ensuring smoother supplies to former member Britain.
But they are also squabbling among themselves over how to share the vaccines they have received, and not all are happy with the European Commission's threat to block some vaccine exports.
EU chief Ursula von der Leyen's executive updated its month-old control mechanism on Wednesday, giving the bloc more power to block vaccine shipments to countries like Britain that produce jabs but do not export them.
The leaders will not be asked to vote on the measure, already provisionally applied, at Thursday's summit, and most would back it if it helps pressure AstraZeneca to boost its deliveries.
But some -- like UK neighbour Ireland, and vaccine producers Belgium and the Netherlands -- are wary of any move to block exports from operations like Pfizer/BioNTech, which supplies both the EU and UK.
If the pharmaceutical industry's global supply chains are disrupted, many countries could lose out, as both British Prime Minister Boris Johnson's government and von der Leyen's commission accepted.
"We are all facing the same pandemic and the third wave makes cooperation between the EU and UK even more important," they said, in a joint statement released to calm nerves after the EU tightened its rules.
The cross-Channel rivals are in discussions about how "to create a win-win situation and expand vaccine supply for all our citizens" but have yet to come to agreement on how to share AstraZeneca doses.
The firm has delivered the EU only 19 million of the 30 million it had promised in the first quarter -- and that pledge was itself a dramatic reduction from the 120 million it contracted for.
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With some EU countries more reliant on the cheaper UK-designed vaccine than others, Brussels' focus has turned to a plant in the Netherlands which the UK had planned to use for its own supplies.
Johnson is holding out, insisting that the UK contract with AstraZeneca must be honoured, but he is worried that Brussels could use the toughened export mechanism to cut Britain off from other EU-made vaccines.
A European diplomat told reporters that the UK and the Commission are negotiating how to better share AstraZeneca doses, and that the EU must not shoulder the shortfall alone.
Another sensitive issue is sharing out the vaccines Europe has received under the Commission's joint buying strategy.
A group of smaller states, led by Austria, is demanding a revision in the distribution method after they came up short in the first quarter.
There is little sympathy in other capitals for their plight, however, as decisions were made on a joint steering committee where Austria and others failed to make use of opportunities to secure more batches.
Discussions are underway on a compromise, but some countries relied more heavily on AstraZeneca compared to more expensive -- but in the end more successful -- suppliers.
And, as one diplomat said: "Some countries just decided to buy fewer vaccines, it's a tactic that can't be blamed on the EU or other member states."
Against this backdrop, Biden's appearance, albeit by video from Washington, may prove a respite. European officials have been delighted with the new US administration's warmer tone.
On the eve of the summit, Biden's top diplomat Antony Blinken wrapped up a two-day visit to Brussels after talks with NATO ministers and top EU officials, promising close coordination.
But fearing leaks from a less than secure videoconference, the leaders do not expect to be able to make decisions on many sensitive topics, and talks initially planned for two days will instead end late Thursday.