The UK medicines regulator says the Oxford-AstraZeneca Covid-19 vaccine is safe after several countries halted its use due to concerns over blood clots. The MHRA insists evidence “does not suggest” the jab causes clots. Reassurances from the WHO and AstraZeneca say that the vaccine is safe, and findings by EU regulators that the occurrence of blood clots is no higher than in the general population. The latest setback to the EU roll-out means that many countries remain vulnerable to a third wave of infections with only a small share of the population vaccinated.