The epidemiology of invasive group A streptococcal infection and potential vaccine implications: United States, 2000-2004.
BACKGROUND
Invasive group A Streptococcus (GAS) infection causes significant morbidity and mortality in the United States. We report the current epidemiologic characteristics of invasive GAS infections and estimate the potential impact of a multivalent GAS vaccine.


METHODS
From January 2000 through December 2004, we collected data from Centers for Disease Control and Prevention's Active Bacterial Core surveillance (ABCs), a population-based system operating at 10 US sites (2004 population, 29.7 million). We defined a case of invasive GAS disease as isolation of GAS from a normally sterile site or from a wound specimen obtained from a patient with necrotizing fasciitis or streptococcal toxic shock syndrome in a surveillance area resident. All available isolates were emm typed. We used US census data to calculate rates and to make age- and race-adjusted national projections.


RESULTS
We identified 5400 cases of invasive GAS infection (3.5 cases per 100,000 persons), with 735 deaths (case-fatality rate, 13.7%). Case-fatality rates for streptococcal toxic shock syndrome and necrotizing fasciitis were 36% and 24%, respectively. Incidences were highest among elderly persons (9.4 cases per 100,000 persons), infants (5.3 cases per 100,000 persons), and black persons (4.7 cases per 100,000 persons) and were stable over time. We estimate that 8950-11,500 cases of invasive GAS infection occur in the United States annually, resulting in 1050-1850 deaths. The emm types in a proposed 26-valent vaccine accounted for 79% of all cases and deaths. Independent factors associated with death include increasing age; having streptococcal toxic shock syndrome, meningitis, necrotizing fasciitis, pneumonia, or bacteremia; and having emm types 1, 3, or 12.


CONCLUSIONS
GAS remains an important cause of severe disease in the United States. The introduction of a vaccine could significantly reduce morbidity and mortality due to these infections.
O'Loughlin
Rosalyn E
RE
Respiratory Diseases Branch, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA. bwf0@cdc.gov
Roberson
Angela
A
Cieslak
Paul R
PR
Lynfield
Ruth
R
Gershman
Ken
K
Craig
Allen
A
Albanese
Bernadette A
BA
Farley
Monica M
MM
Barrett
Nancy L
NL
Spina
Nancy L
NL
Beall
Bernard
B
Harrison
Lee H
LH
Reingold
Arthur
A
Van Beneden
Chris
C
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002675:Child, Preschool; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D009026:Mortality; D011159:Population Surveillance; D013290:Streptococcal Infections / Q000276:immunology / Q000401:mortality* / Q000517:prevention & control; D022541:Streptococcal Vaccines / Q000627:therapeutic use*; D013297:Streptococcus pyogenes / Q000276:immunology* / Q000472:pathogenicity; D014481:United States / Q000453:epidemiology