DES MOINES, Iowa (AP) — Iowa public health officials said Tuesday they were temporarily stopping the use of the Johnson & Johnson coronavirus vaccine as federal health agencies investigate incidents of rare blood clots.

The Iowa Department of Public Health announced the pause at the recommendation of the Centers for Disease Control and Prevention, which is reviewing data involving six reported U.S. cases of a severe type of blood clot in individuals after receiving the J&J vaccine. More than 6.8 million doses of the J&J vaccine have been given in the U.S.

Iowa was to receive just 1,800 doses of J&J vaccine this week, public health officials said. The state is still expecting to get more than 43,200 doses of Pfizer vaccine and 31,800 doses of Moderna.

White House COVID-19 Response Coordinator Jeff Zients said in a statement that halting use of J&J vaccine will not have a significant impact on the overall vaccination plan.

Iowa posted an additional 565 confirmed virus cases Tuesday and no additional deaths.

The state has posted 3,666 coronavirus cases and 35 deaths in the last seven days, according to CDC data. The data shows that 29% of the new cases are among people from age 18 to 29, reflecting a recent trend of young adults spreading the virus.

There were 220 infected people being treated in Iowa hospitals Tuesday, a figure that remained above 200 for more than a week after dropping below that mark in late March and early April.