Two new cases of blood clots after administration of Johnson & Johnson’s single-dose Covid-19 vaccine are being investigated by federal health officials, the U.S. Centers for Disease Control and Prevention said on April 27.

The U.S. Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) lifted the restrictions on the Johnson & Johnson Covid-19 vaccine on April 23. The announcement came after the FDA’s Advisory Committee on Immunization Practices (ACIP) met for a second time to discuss the data, with the benefits outweighing the risks.

Johnson & Johnson said on April 20 the company will resume rolling out its Covid-19 vaccine in Europe after the region’s medical regulator said the benefits of the shot outweigh the risk of very rare, potentially lethal blood clots.

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.