Blood Clot Risk Much Higher From Covid Than With Vaccines: UK Study

The findings appear to bolster the decision to continue using AstraZeneca's vaccine, which has been dogged by safety concerns, to protect people from hospitalization and death.

Covid-19 patients face a much higher risk of developing blood clots than those vaccinated with AstraZeneca Plc or Pfizer Inc.'s shots, according to a large U.K. study. For every 10 million people who receive the first dose of AstraZeneca, about 66 more will suffer from a blood-clotting syndrome than during normal circumstances, according to the study published in the British Medical Journal. This figure compares with 12,614 more incidences recorded in 10 million people who have tested positive for Covid-19. The study followed 29 million people who received their first doses of either AstraZeneca or Pfizer vaccine between December, 2020 and April and also tracked about 1.7 million Covid-19 patients. The findings appear to bolster the decision to continue using AstraZeneca's vaccine, which has been dogged by safety concerns, to protect people from hospitalization and death. Many developed countries have, however, limited its use to older adults because of concerns about an elevated risk of blood clots affecting the younger population.