OMAHA, Neb. (AP) — The Nebraska woman who developed blood clots two weeks after receiving Johnson & Johnson's COVID-19 vaccine remains in critical condition after also having a stroke.

The doctors who have been treating the woman at the Nebraska Medical Center in Omaha described the case Wednesday in a letter to the New England Journal of Medicine. State and federal health officials are still investigating whether the 48-year-old woman's blood clots are linked to the vaccine.

The report said the woman who had no history of medical problems had abdominal pain and didn’t feel well for three days before going to a hospital. Doctors first found blood clots in her abdomen and abnormally low levels of platelets in her blood. After she was transferred to the Nebraska Medical Center, the woman developed a headache and more clots were found in her head. Then the woman had a stroke after a blood vessel in her brain ruptured.

The doctors who are treating the woman said the case suggests that the rare development of blood clots like this could be related to the vaccine.

The Nebraska case is one of six cases of blood clots nationwide that prompted federal health officials to recommend Tuesday that the J&J vaccine not be used while those cases are being investigated. One of the people who developed blood clots has since died.