Global health experts were under increasing pressure to clear up questions over the safety of AstraZeneca's COVID-19 shot on Tuesday, as Sweden and Latvia joined countries suspending their use in a further blow to Europe's vaccination rollout.
A World Health Organization (WHO) committee of experts was reviewing isolated cases of bleeding, blood clots and low platelet counts in people vaccinated in close dialogue with the European Medicines Agency (EMA), which was also meeting.
The EMA would hold a news conference at 1300 GMT and the WHO committee may also issue a statement on Tuesday, spokespeople for the EU executive and the U.N. health agency said.
The European Union's largest members - Germany, France and Italy - suspended the use of AstraZeneca's vaccine on Monday pending the outcome of an investigation into the reports.
The addition of Sweden and Latvia on Tuesday brought to more than a dozen the number of EU countries to act since reports first emerged of thromboembolisms affecting people after they got the AstraZeneca shot.
The WHO and EMA had earlier joined AstraZeneca in saying there is no proven link, but some experts said rare cases of highly unusual cerebral thrombosis in younger people did appear to indicate a causal link to the AstraZenica shot.
"Unfortunately, the ... brain thrombosis is likely due to the AstraZeneca vaccine. And it affects younger people without risk factors," said Karl Lauterbach, health spokesman for Germany's Social Democratic Party.
"But because the risk is only about 1 in 250,000, the benefits predominate," he added in a tweet.
European epidemiologists remained baffled that similar cases had not occurred in unusual numbers in Britain, which began using AstraZeneca earlier and has administered more than 10 million doses.
"These symptoms have not yet been observed there," said Stephan Becker, head of the Institute for Virology at Philipps University Marburg.
"This is a very unfortunate situation, but if there is such a suspicion, then it must be investigated and the vaccination must be stopped for that time."
Nicola Magrini, the director general of Italy's medicines authority AIFA, told daily la Repubblica in an interview that the choice to suspend the vaccines was "political".
He called the AstraZeneca vaccine safe and said its benefit to risk ratio was "widely positive". There have been eight deaths and four cases of serious side-effects following vaccinations in Italy, he added.
Governments say they acted out of an abundance of caution but the move deprives them of vitally-needed doses to step up vaccination campaigns that have got off to a slow start due to scarce supply.
The EU has administered just 11 shots so far for every 100 of its residents, while Israel - a world leader in vaccination - has given 108 doses per 100 residents, according to Our World in Data.
At the same time a third wave of infection, driven by more infectious viral variants, threatens to worsen Europe's year-old coronavirus pandemic that has claimed 575,000 lives and further delay recovery from a pandemic economic slump.
Deutsche Bank on Tuesday slashed 2021 economic growth forecasts for the euro area by a whole percentage point, citing spillover of the ongoing pandemic-linked activity restrictions.
In Germany, Health Minister Jens Spahn stated on Monday that the decision to suspend AstraZeneca was not political but based on expert advice.
Sources said he had no choice but to act after Germany's vaccine watchdog identified an unusual number of cases of rare cerebral vein thrombosis. Of 1.6 million people in Germany who had got AstraZeneca, seven fell ill and three died.
Yet the risk of dying of COVID is still orders of magnitude greater, especially among those most vulnerable such as the elderly, said Dirk Brockmann, an epidemiologist at the Robert Koch Institute for infectious diseases.
"In the risk groups the chance of dying of COVID is much, much higher. That means one is probably 100,000 times more likely to die of COVID than because of an AstraZeneca vaccine," Brockmann told ARD public television.
The political fallout was immediate, with Chancellor Angela Merkel cancelling vaccine strategy talks on Wednesday that had been due to discuss distributing the AstraZeneca shot to family doctors to speed up its rollout.
Bavarian state premier Markus Soeder, a contender to succeed Merkel at a general election this September, called for the AstraZeneca shot to be made available to anyone who wanted it. A senior aide warned that, without AstraZeneca, Germany's vaccine drive was at risk of failing.
IN THE HOT SEATIn France, Health Minister Olivier Veran told reporters the risk-reward ratio for the AstraZeneca vaccine remained positive.
Yet the latest setback has dealt a further blow to the Anglo-Swedish pharmaceuticals group, which has clashed with the EU's executive Commission over its supply contract and fallen short of its delivery commitments.
AstraZeneca's chief executive Pascal Soriot is in the "hot seat" over delays to deliveries and must provide more details of his production plans, France's Industry Minister Agnes Pannier-Runacher said.
"In any business, there is a fiduciary responsibility, you have to be accountable," Pannier-Runacher told France Info radio. "When you do not honour a contract, this can cause problems, individual problems."
AstraZeneca said last week it would try to deliver 30 million doses to the European Union by the end of March, down from a contractual obligation of 90 million and a previous pledge made last month to deliver 40 million doses.