Epidemiology and Infection

Invasive group A streptococcal infections in the San Francisco Bay area, 1989–99

D. J. PASSARO a1c1, D. S. SMITH a1p1, E. C. HETT a1p2, A. L. REINGOLD a2, P. DAILY a1, C. A. VAN BENEDEN a3 and D. J. VUGIA a4
a1 California Emerging Infections Program, Oakland, CA 94617, USA
a2 Division of Public Health Biology and Epidemiology, University of California at Berkeley, Berkeley, CA 94720, USA
a3 Division of Bacterial and Mycotic Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
a4 Disease Investigations and Surveillance Branch, California Department of Health Services, Berkeley, CA 94704, USA


To describe the epidemiology of invasive group A streptococcal (iGAS) infections in the San Francisco Bay Area, population-based active surveillance for laboratory-confirmed iGAS was conducted by the California Emerging Infections Program in three California counties. From January 1989 to December 1999, 1415 cases of iGAS were identified. Mean iGAS incidence was 4·06/100 000 person-years and case fatality ratio was 13%, with no linear trends over time. Incidence was lowest in adolescents, was higher in men than women (4·4 vs. 3·2/100 000 person-years), and was higher in African–Americans (6·7) than in non-Hispanic (4·1) or Hispanic (3·4) Whites, Asians (2·2) or Native Americans (1·7/100 000 person-years). Injecting drug use was the riskiest underlying condition and was associated with the highest attributable risk. Cases were associated with several underlying conditions, but 23% occurred in previously healthy persons. From 1989–1999, iGAS infections in the San Francisco Bay Area became neither more common nor more deadly.

(Accepted July 15 2002)

c1 Author for correspondence: Division of Epidemiology and Biostatistics, University of Illinois-Chicago School of Public Health, 1603 W. Taylor Street, Room 958, Chicago, IL 60612, USA.
p1 Current affiliation: Kaiser Permanente-Redwood City Medical Center, Redwood City, CA 94063, USA.
p2 Current affiliation: Harvard School of Public Health, Boston, MA 02115, USA.