WASHINGTON: A US health agency raised concerns Tuesday that AstraZeneca may have included out-of-date information during trials of its Covid-19 vaccine, a day after the company said its drug was highly effective in preventing the disease.

The Anglo-Swedish pharma giant stood by its assessment of the results of its US trials, saying it would publish new data “within 48 hours” in response to concerns raised by the US National Institute for Allergies and Infectious Diseases. The fresh problems for the drugmaker, which had on Monday hailed its vaccine as 79 percent effective at preventing Covid-19, come as Europe continues to wrangle over shortages of the jab and after weeks of safety concerns. With AstraZeneca delivering only 30 percent of the doses it promised the EU for the first quarter, Germany threw its weight behind a ban on European exports of the jab, while also announcing strict virus measures over Easter to contain spiralling infections. Meanwhile, Britain marked the anniversary of its first coronavirus lockdown by holding a minute’s silence for the more than 126,000 of its citizens who have died from Covid-19, the fifth-highest death toll in the world. The global death toll now stands at more than 2.7 million.

AstraZeneca’s vaccine had been hailed as a potential game-changer in the fight against the pandemic as it is cheaper and easier to store than many of its rivals, making it more accessible for poorer nations. But public confidence in the drug has tumbled after more than a dozen countries temporarily suspended its rollout because of isolated cases of blood clots in people who had received a dose. The EU’s medicines regulator and the World Health Organization insist there is no evidence linking the vaccine to blood clots, and none was found in the large-scale trials in the US.

Scant supplies of AstraZeneca doses in Europe have meanwhile hampered the continent’s vaccine rollouts, which lag far behind countries like the UK and Israel in their pace.