AUSTIN, Texas (AP) — Texas joined other states Tuesday in suspending the use of the Johnson & Johnson COVID-19 vaccine pending the outcome of a federal investigation into six cases in which women who received the drug developed potentially dangerous blood clots.

More than 500,000 doses of the single-dose J&J vaccine have been administered in Texas, and health officials say none of the six reported cases of blood clots occurred in the state.

Providers will continue offering the Pfizer and Moderna vaccines as planned.

The Centers for Disease Control and Prevention and the Food and Drug Administration said Tuesday that they were investigating unusual clots that occurred 6 to 13 days after vaccination. The clots occurred in veins that drain blood from the brain, and the patients also had low platelet counts. All six cases were in women between the ages of 18 and 48, including one who died.

More than 6.8 million doses of the J&J vaccine have been given in the U.S., the vast majority with no or mild side effects. The potential adverse reactions appear to be extremely rare, occurring in fewer than one in every million recipients.

According to the Department of State Health Services, Texas has not been notified of any change in vaccine distribution. About 32% of the population in Texas is at least partially vaccinated against COVID-19, according to the U.S. Centers for Disease Control and Prevention. Almost 20% of Texas residents are fully vaccinated.

Johnson & Johnson said Tuesday that it was delaying the rollout of its coronavirus vaccine in Europe amid the U.S. probe.

Nearly 50,000 people have died of COVID-19 in Texas so far, ranking the state third nationally. Meantime, more than 3 million COVID-19 cases have been reported in Texas, including more than 5,400 new cases and almost 1,900 previously unreported cases reported Tuesday.