LOS ANGELES - (Xinhua) -- The U.S. Food and Drug Administration has restricted use of the Johnson & Johnson COVID-19 vaccine (Janssen vaccine) to individuals 18 years of age and older who cannot or do not want to get other COVID-19 vaccines, citing Rare risk of blood clots.

"After conducting an updated analysis, evaluation, and examination of reported cases, the FDA has determined that the risk of thrombosis with thrombocytopenic syndrome, a syndrome of rare, potentially life-threatening blood clots, in addition to low levels of platelets appears," the FDA said in a statement. Symptoms appearing approximately one to two weeks after administration of the Janssen vaccine warrant a reduction in the authorized use of the vaccine.

"Our work reflects our updated analysis of the risk of thrombotic thrombocytopenia after administration of this vaccine and limits the use of the vaccine to specific individuals," said Peter Marks, director of the FDA's Center for Biologicals Evaluation and Research.

The Johnson & Johnson vaccine was authorized for emergency use in the United States on February 27, 2021.

As of March 18 this year, the Food and Drug Administration and the US Centers for Disease Control and Prevention have identified 60 confirmed cases of thrombocytopenia, including nine deaths.