Key points are not available for this paper at this time.
From the Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota 2Postdoctoral trainee, USPHS Training Grant T1 Al 194-05. Presently Epidemic Intelligence Service Officer, National Communicable Disease Center, U.S. Public Health Service, assigned to Division of Infectious Diseases, University of Maryland School of Medicine
DuPont et al. (Tue,) studied this question.