Error processing SSI file
Error processing SSI file
Error processing SSI file
Error processing SSI file
Error processing SSI file
Error processing SSI file
Error processing SSI file
Error processing SSI file

Weekly Report: Influenza Summary Update

Week ending December 20, 2003-Week 51

Error processing SSI file

The following information may be quoted:

Synopsis:

This report is being provided 1 day earlier than usual due to the holiday period. Therefore, fewer data than usual are available for some surveillance components. Influenza activity in the United States continued to increase during week 51 (December 14 - 20, 2003). The proportion of patient visits to sentinel providers for influenza-like illness (ILI) overall was 7.7%, which is above the national baseline of 2.5%.   Although ILI activity continues to increase overall, activity in some states, including Texas and Colorado, has declined in recent weeks. The proportion of deaths attributed to pneumonia and influenza was 7.8%, which equals the epidemic threshold for the week. Forty-five state health departments, New York City, and the District of Columbia reported widespread influenza activity, 4 states reported regional activity, and 1 state reported local influenza activity. Availability of trivalent inactivated influenza vaccine is limited; additional doses of the vaccine previously purchased by CDC will be shipped to state and local public health agencies in January. The live, attenuated influenza vaccine continues to be available in both the private and public sectors.

Laboratory Surveillance*:

During week 51, there were insufficient data from WHO and NREVSS collaborating laboratories to report laboratory results.

Antigenic Characterization:

CDC has antigenically characterized 330 influenza viruses collected by U.S. laboratories since October 1: two influenza A (H1) viruses, 326 influenza A (H3N2) viruses, and 2 influenza B viruses. The hemagglutinin proteins of the influenza A (H1) viruses were similar antigenically to the hemagglutinin of the vaccine strain A/New Caledonia/20/99. Of the 326 influenza A (H3N2) isolates that have been characterized, 80 (25%) were similar antigenically to the vaccine strain A/Panama/2007/99 (H3N2), and 246 (75%) were similar to the drift variant, A/Fujian/411/2002 (H3N2). Both influenza B viruses characterized were similar antigenically to B/Sichuan/379/99, which is in the 2003-04 vaccine.

Pneumonia and Influenza (P&I) Mortality Surveillance:

During week 51, 7.8% of all deaths reported by the vital statistics offices of 122 U.S. cities were due to pneumonia and influenza. This percentage is at the epidemic threshold of 7.8% for week 51.

Pneumonia And Influenza Mortality

View Full Screen

Influenza-like Illness Surveillance *:

During week 51, 7.7%*** of patient visits to U.S. sentinel providers were due to ILI. This percentage is above the national baseline of 2.5%. The percentage of patient visits for ILI increased in 5 of the 9 surveillance regions, but has continued to decline in the West South Central region (6.8% for week 51 compared with 11.3% during week 47). On a regional level**, the percentage of visits for ILI was highest in the East North Central region (9.6%), followed by the Pacific region (9.0%), West North Central region (8.8%), South Atlantic region (7.9%), East South Central region (7.8%), West South Central region (6.8%), New England region (6.3%), Mid-Atlantic region (5.8%), and the Mountain region (4.4%). Due to wide variability in regional level data, it is not appropriate to apply the national baseline to regional level data.

Bar Chart for Influenza-like Illness
View Chart Data | View Full Screen

Influenza Activity as Assessed by State and Territorial Epidemiologists**:

Influenza activity was reported as widespread in 45 states (Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, and Wyoming), New York City, and the District of Columbia. Regional activity was reported by 4 states (Florida, Louisiana, New Hampshire, and Oklahoma), and Hawaii reported local activity.

U. S. map for Weekly Influenza Activity
View Full Screen

Influenza Activity in Selected States:

Although influenza activity continues to increase in the United States overall, activity is declining in certain states. Two states experiencing a decline in activity are Colorado and Texas. Influenza activity in both states continues to be widespread, but in Texas, outpatient visits for ILI have declined from a peak of 14.4% during week 47 (the week ending November 22) to 7.4% during week 51. In Colorado, the percentage of patient visits for ILI peaked at 4.3% during week 48 (the week ending November 29) and has declined to 1.1% during week 51.

Vaccine Availability:

In the private sector, trivalent inactivated influenza vaccine is no longer available for sale by the manufacturers, although some vaccine may still be available through private wholesale/distribution companies. The live, attenuated influenza vaccine continues to be available for purchase from Wyeth Pharmaceuticals (Collegeville, Pennsylvania, telephone 800-358-7443).

In the public sector, the live, attenuated influenza vaccine is also available for immediate purchase through a CDC contract. Additional doses of trivalent inactivated influenza vaccine previously purchased through CDC contracts will be shipped to state and local public health agencies in early to mid-January.

U. S. map for Weekly Influenza Activity
View Full Screen


* Reporting is incomplete for this week. Numbers may change as more reports are received.

** Influenza activity is defined as influenza-like illness and/or culture-confirmed influenza.

*** Surveillance Regions: New England (Connecticut, Maine, Massachusetts, New Hampshire, Vermont, Rhode Island); Mid-Atlantic (New Jersey, New York City, Pennsylvania, Upstate New York); East North Central (Illinois, Indiana, Michigan, Ohio, Wisconsin); West North Central (Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, South Dakota); South Atlantic (Delaware, Florida, Georgia, Maryland, North Carolina, South Carolina, Virginia, Washington, D.C., West Virginia); East South Central (Alabama, Kentucky, Mississippi, Tennessee); West South Central (Arkansas, Louisiana, Oklahoma, Texas); Mountain (Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, Utah, Wyoming); Pacific (Alaska, California, Hawaii, Oregon, Washington)

Report prepared December 24, 2003

Error processing SSI file
Error processing SSI file
Error processing SSI file
Error processing SSI file