Neonatal GBS incidence falls; stricter guidelines credited.
The incidence of invasive group B streptococcal disease declined among infants aged 0-6 days after stricter measures for perinatal prevention were widely adopted across the country in 2002, federal scientists have reported.
However, there was a significant increase in the disease among black infants during this period, a finding that is "particularly concerning and requires investigation," said Christina R. Phares, Ph.D., of the Centers for Disease Control and Prevention (CDC) and her associates.
The revised guidelines recommended antenatal culture-based screening as the optimal method for identifying candidates for intrapartum chemoprophylaxis.
The CDC investigators assessed epidemiologic trends among 14,573 cases of invasive group B streptococcal (GBS) disease identified by a national surveillance program between 1999 and 2005, the most recent year for which data are available.
In 2005, there were an estimated 21,500 cases of invasive GBS in the United States, including 1,700 fatalities (JAMA 2008; 299:2056-65).
The overall incidence of invasive GBS disease among adults and children in 2005 was 12.8 per 100,000 population in blacks, 6.5 per 100,000 in whites, and 5.1 per 100,000 in all other races combined.
Mortality also was significantly higher for black neonates and black adults aged 45 years and older than for other racial groups.
Early-onset GBS (before 1 week of age) decreased by 27%, from 0.47 per 1,000 live births before the revised guidelines to 0.34 per 1,000 live births in 2003-2005. This is "very dose" to the impact that the stricter guidelines were predicted to have, the researchers said. However, there were small increases in incidence in 2004 and 2005, almost all of which occurred among black infants.
The incidence of late-onset GBS (age 7-89 days) remained stable, averaging 0.34 cases per 1,000 live births throughout the 7-year study. Similarly, the incidence of childhood disease (90 days-14 years) remained stable at 0.56 per 100,000 population, with 61% of these cases occurring in children aged 3-12 months.
In contrast, the incidence increased significantly among adults--by 48% in people aged 15-64 years and by 20% in people aged 65 and older. This might be in part because of the increase in underlying medical conditions such as diabetes in this age group, Dr. Phares and her associates said.
Serotype data suggested that a pentavalent conjugate vaccine potentially could have prevented "up to 96% of neonatal disease and 88% of pediatric, adult, and pregnancy-associated disease, which translates to approximately 19,000 cases" of the 21,500 estimated to have occurred in 2005.
"Maternal GBS vaccination trials should be a public health priority, followed by expanded vaccine development to target disease among elderly and younger adults with chronic underlying conditions," they concluded.
BY MARY ANN MOON
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|Title Annotation:||Infectious Diseases|
|Author:||Moon, Mary Ann|
|Date:||Jun 1, 2008|
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