Officials are warning patients who take medicine for rheumatoid arthritis that they might be at risk for serious fungal infections.

The Food and Drug Administration said that 12 people have died, and the agency has received 240 reports of infections. In at least 21 of the cases, doctors said they initially did not recognize the problem.

The FDA is ordering Humira, Cimizia, Enbrel and Remicade to have stronger warnings about the problem.

If you are on any of these medications, you are urged to call your doctor if you develop a fever, cough, shortness of breath or fatigue.