All eight of the cases reported in the U.S. are women.
Meanwhile, across the Atlantic, the European Medicines Agency this week concluded that a link between the vaccine and rare blood clotting cases was possible but that the benefits of the shot outweighed the risks.
Johnson & Johnson had delayed its rollout of the shot in Europe while the U.S. investigated. But after the EMA ruling, the company resumed shipments to the continent.
Some European countries are limiting its use. France, for example, will restrict it to those older than 55. Italy will allow it only for those over age 60. The company is committed to providing 55 million doses to Europe by the end of June.
Even if vaccinations resume in the U.S., supply remains uncertain.
Last week, the FDA ordered a temporary halt to the production of drug substance at an Emergent BioSolutions plant in Baltimore.
Just two weeks earlier, the FDA had turned COVID-19 vaccine manufacturing at the plant over to J&J.
For its part, J&J has pledged to deliver 100 million doses to the U.S. during the first half of the year.