Grace Eldering, 87, a bacteriologist who co-developed a vaccine against whooping cough. Miss Eldering, who herself suffered from whooping cough when she was 5, developed the vaccine with Dr. Pearly L. Kendrick during the 1930s at the state Department of Public Health's Western Michigan Division Laboratory in Grand Rapids, Mich. Their vaccine remains in use against whooping cough, an infectious respiratory disease that once killed up to 6,000 children a year nationwide. Miss Eldering, born in Montana, earned a doctorate in science from Johns Hopkins University in 1941 and had worked from 1928 to 1951 as a bacteriologist with the Michigan Department of Public Health. She was director of the Grand Rapids laboratory from 1951 until her retirement in 1969. In Grand Rapids on Wednesday.