A vaccine on the market since 2000 has reduced the incidence of childhood pneumonia and meningitis, particularly among black Americans, according to a study in the May 12 issue of The Journal of the American Medical Association.Blacks in the United States historically have had a higher incidence of the two diseases than whites. The widest disparities occur among children in the first two years of life and among adults 18 to 64 years old.A new vaccine for children, Prevnar, was recommended in October 2000. Before the vaccine’s release, blacks had a 2.9 times higher risk of contracting pneumonia and meningitis than whites; afterwards, that risk dropped to 2.2 times higher, according to the study by the U.S. Centers for Disease Control and Prevention.