Two National Institutes of Health (NIH)-supported trials of an experimental malaria vaccine in healthy Malian adults found that all three tested regimens were safe. One of the trials enrolled 300 healthy women ages 18 to 38 years who anticipated becoming pregnant soon after immunization. That trial began with drug treatment to remove malaria parasites, followed by three injections spaced over a month of either saline placebo or the investigational vaccine at one of two dosages.