Europe’s drug regulator found a possible link between Johnson & Johnson’s Covid-19 vaccine and rare blood clotting issues in adults who received doses in the United States, but backed its overall benefits against any risks.

China’s CanSino Biologics will initiate clinical trials of an experimental Covid-19 vaccine that is inhaled, instead of injected.

Just more than half of U.S. adults have received at least one Covid-19 vaccine dose, data from the U.S. Centers for Disease Control and Prevention showed on April 18, with nearly 130 million people aged 18 years or more having received their first shot.

A U.S. panel will meet again next week to discuss whether the pause on the use of Johnson & Johnson’s Covid-19 vaccine should continue, after delaying a vote on the matter earlier this week.

There is a much higher risk of brain blood clots from Covid-19 infection than there is from vaccines against the disease, British researchers said on April 15, after the rollout of inoculations was disrupted by reports of rare clots.

A U.S. health advisory panel on April 14 is set to review six reported cases of rare blood clots in women who received Johnson & Johnson’s Covid-19 vaccine one day after federal regulators paused the use of the shot to assess the issue.

U.S. federal health agencies on April 13 recommended pausing the use of Johnson & Johnson’s Covid-19 vaccine after six women under 50 given the shot developed rare blood clots, dealing a fresh setback to efforts to tackle the pandemic.

Europe’s drug regulator is reviewing reports of rare blood clots in four people who received Johnson & Johnson’s Covid-19 vaccine and expanded its probe into AstraZeneca’s shot to include reports of a bleeding condition.

The European Medicines Agency (EMA) said on April 7 it had found a possible link between AstraZeneca’s coronavirus vaccine and reports of very rare cases of blood clots in people who had received the shot.

The World Health Organization expects there will be no reason to change its assessment that the benefits of the AstraZeneca vaccine against Covid-19 outweigh any risks, a regulatory official told a news conference on April 6.