A United States health agency raised concerns on Tuesday that AstraZeneca may have included out-of-date information during trials of its Covid-19 vaccine, the day after the company said its drug was highly effective in preventing the disease.
The news comes as Europe continues to wrangle over supplies of the jab, and after weeks of uncertainty centred on fears it was linked to an increased risk of blood clots.
Germany, one of the bloc's key players, on Tuesday threw its weight behind an EU export ban, as it announced strict virus measures would be imposed for five days over Easter to contain spiralling infections.
AstraZeneca had said on Monday that stage three US trials had shown its vaccine was 79% effective at preventing the disease.
But in a late-night release, the National Institute of Allergy and Infectious Diseases (Niaid) flagged concerns.
Niaid said a monitoring board "expressed concern that AstraZeneca may have included outdated information from that trial, which may have provided an incomplete view of the efficacy data."
"We urge the company to work with the DSMB (Data and Safety Monitoring Board) to review the efficacy data and ensure the most accurate, up-to-date efficacy data be made public as quickly as possible."
AstraZeneca 'problem'
Meanwhile, a spat is simmering between Britain and the EU over much-needed supplies of the AstraZeneca jab, which is cheaper and easier to store than many of its rivals.
European officials are furious that the Anglo-Swedish company has been able to deliver its UK contract in full while falling short on its supplies to the EU.
German leader Angela Merkel on Tuesday said, "We have a problem with AstraZeneca," as she backed an EU threat to ban AstraZeneca vaccines produced in the EU from being exported -- unless it delivers more of the 90 million doses it agreed to supply in the first quarter of 2021.
And public confidence in the drug has tumbled after several countries suspended its rollout because of isolated cases of blood clots.
A survey by British pollsters YouGov showed that a majority of people in the biggest EU states view the vaccine as unsafe.
The EU's medicines regulator and the WHO insist there is no evidence linking the drug to blood clots, and none was found in the large-scale trials in the US.
'We have a new virus'
Chancellor Merkel ordered the harsh nationwide shutdown, warning a potent strain of coronavirus was raging through the EU's most populous country.
"The situation is serious," she said. "Case numbers are rising exponentially and intensive care beds are filling up again."
A variant first identified in the United Kingdom has become the dominant strain circulating in Germany, the under-pressure leader said, adding that "we are in a new pandemic."
"Essentially, we have a new virus... it is much deadlier, much more infectious and infectious for much longer."
Cultural, leisure and sporting facilities will stay shuttered through to April 18, and a lockdown will come into force between April 1 and 5, as Christians celebrate Easter.
Almost all shops will be closed across the five days, and religious services will be moved online.
