Study of Oxford-AstraZeneca vaccinations in children paused after blood clots emerge in adults

UK’s drug regulator is investigating rare cases of blood clots in adults who were given Oxford-AstraZeneca shot. No safety issues have arisen in children’s trial, Oxford says.

A vial of the Covishield vaccine, developed by AstraZeneca Plc and the University of Oxford and manufactured by Serum Institute of India (File photo) | Patrick Meinhardt | Bloomberg

London: Vaccinations of children in a study of the Covid-19 shot developed by AstraZeneca Plc and the University of Oxford have been paused while the U.K.’s drug regulator investigates rare cases of blood clots in adults.

The vaccine researchers are awaiting the results of a review by the Medicines and Healthcare Products Regulatory Agency, the U.K.’s drug watchdog, “before further vaccinations,” the university said in an emailed statement. No safety issues have arisen in the children’s trial, Oxford said.

The action comes after a growing number of reports of rare brain blood clots in younger adults have led some countries, including several in the European Union, to suspend use of the vaccine in certain age groups. Germany halted use of the Astra-Oxford vaccine for people younger than 60 last week, while Canada has limited its use to those more than 55 years old.

Drug regulators in the U.K. and EU have said that a connection between the clots and the vaccine is possible but unclear, and that the benefits continue to outweigh the risks. An update from the European Medicines Agency planned this week may indicate a potential link between the drugmaker’s shot and the blood clots, Italian newspaper Il Messaggero reported Tuesday, quoting Marco Cavaleri, chair of the EMA’s vaccine evaluation team.

U.S. Trial Planned

Cavaleri’s comments were personal and preliminary, the drug regulator said in an emailed statement. The EMA referred to a March 31 statement in which it said it would issue an updated recommendation on the issue during its plenary meeting that takes place this week. The agency said this will most likely happen April 7.

The U.K.’s regulator said Saturday that it had identified 30 cases of a rare combination of blood clots and low platelets in people in Britain who had received the Astra shot through March 24, of whom seven died.

The Oxford trial plans to enroll 300 children and adolescents aged 6 to 17, the university said when it began the study in February. As many as 240 participants will receive the coronavirus vaccine and the remainder a meningitis shot. Initial data from the trial is expected by the summer, Oxford said at the time.

Astra is planning to start a larger U.S. trial for children, similar to those run by Pfizer Inc. and Moderna Inc., in the coming months.

Parents and children continue to attend all scheduled visits and can contact the trial sites if they have any questions, the university said in the statement. The Wall Street Journal reported the pause in the study earlier. — Bloomberg