Creating a model program for influenza surveillance in California: results from the 2005-2006 influenza season.

BACKGROUND: Influenza surveillance is valuable for monitoring trends in influenza-related morbidity and mortality. Using the 2005-2006 influenza season as an example, this paper describes a comprehensive influenza surveillance program used by the California Department of Public Health (CDPH). METHODS: Data collected from patients evaluated for acute respiratory illness in a given week were reported and summarized the following week, including (1) electronic hospital pneumonia and influenza admission and antiviral usage records from Kaiser Permanente, (2) sentinel provider influenza-like illness (ILI) reports, (3) severe pediatric influenza case reports (e.g., children either hospitalized in intensive care or expired), (4) school clinic ILI evaluations, and (5) positive influenza test results from a network of academic, hospital, commercial, and public health laboratories and the state CDPH Viral and Rickettsial Disease Laboratory. RESULTS: Influenza activity in California in the 2005-2006 season was moderate in severity; all clinical and laboratory markers rose and fell consistently. Extensive laboratory characterization identified the predominant circulating virus strain as A/California/7/2004(H3N2), which was a component of the 2005-2006 influenza vaccine; 96% of samples tested showed adamantane resistance. CONCLUSIONS: By using multiple, complementary surveillance methods coupled with a strong laboratory component, the CDPH has developed a simple, flexible, stable, and widely accepted influenza surveillance system that can monitor trends in statewide influenza activity, ascertain the correlation between circulating strains with vaccine strains, and assist with detection of new strain variants. The methods described can serve as a model for influenza surveillance in other states.

Beliefs about appropriate antibacterial therapy, California.

To our knowledge, previous population-based surveys have not assessed misconceptions about antibacterial drug use over time. We documented a 26.3% decline in a key misconception in California women in 2003 compared to 2000; declines varied significantly by education level. Educational campaigns specifically designed to influence important subpopulations are needed.

Population-based trends in pediatric hemolytic uremic syndrome in California, 1994-1999: substantial underreporting and public health implications.

This paper describes the epidemiology of childhood hemolytic uremic syndrome (HUS) in California, for which hospitalization data were used, and the proportion of cases reported to public health authorities. HUS discharge data for children < or =17 years of age were extracted from the population-based California Patient Discharge Data Set for 1994-1999 and were linked electronically with HUS reports to public health authorities. Incidence rates per 100,000 children were calculated. The authors identified 585 HUS hospitalizations; 369 were incident cases. The average HUS incidence rate was 0.67 (95% confidence interval: 0.61, 0.74); rates rose modestly from 1994 (0.59, 95% confidence interval: 0.44, 0.78) to 1997 (0.80, 95% confidence interval: 0.63, 10.0) and decreased modestly thereafter (0.59, 95% confidence interval: 0.45, 0.77). Rates were highest for northern California children < or =5 years of age (1.85, 95% confidence interval: 1.55, 2.19). The hospital case-fatality rate was 2.7% (95% confidence interval: 1.1, 4.4); the median charge was $39,500 per child. Only 43.9% of HUS cases in the California Patient Discharge Data Set were reported to public health authorities. Despite heightened efforts to control Shiga toxin-producing Escherichia coli exposures (the predominant cause of childhood HUS in the United States), HUS incidence rates remained relatively stable in California. Reporting HUS cases to public health authorities is important for disease control.