Weekly U.S. Influenza Surveillance Report | Seasonal Influenza (Flu) | CDC

Weekly U.S. Influenza Surveillance Report | Seasonal Influenza (Flu) | CDC

2015-2016 Influenza Season Week 43 ending October 31, 2015

Flu activity is low in the United States, but CDC has received reports of early outbreaks in institutions across the country. Most of these outbreaks have been attributed to H3N2 viruses. Flu causes millions of illnesses, hundreds of thousands of hospitalizations and thousands of deathsevery season.

More than 123 million doses of 2015-16 flu vaccine have been distributed so far. This season’s vaccines have been updated to better match circulating viruses. CDC recommends a yearly flu vaccine for everyone 6 months and older. While how well the vaccine works can vary, flu vaccine is the best way to protect against flu. Vaccination can reduce flu illnesses, doctors' visits, and missed work and school, as well as prevent hospitalizations.

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Synopsis:

During week 43 (October 25-31, 2015), influenza activity was low in the United States.

• Viral Surveillance: The most frequently identified influenza virus type reported by public health laboratories in week 43 was influenza A viruses, with influenza A (H3) viruses predominating. The percentage of respiratory specimens testing positive for influenza in clinical laboratories is low.
• Pneumonia and Influenza Mortality: The proportion of deaths attributed to pneumonia and influenza (P&I) was below their system-specific epidemic threshold in both the NCHS Mortality Surveillance System and the 122 Cities Mortality Reporting System.
• Influenza-associated Pediatric Deaths: No influenza-associated pediatric deaths were reported.
• Outpatient Illness Surveillance: The proportion of outpatient visits for influenza-like illness (ILI) was 1.4%, which is below the national baseline of 2.1%. All 10 regions reported ILI below region-specific baseline levels. Puerto Rico experienced low ILI activity, New York City and 50 states experienced minimal ILI activity, and the District of Columbia had insufficient data.
• Geographic Spread of Influenza: The geographic spread of influenza in Guam was reported as regional; two states reported local activity; Puerto Rico and 40 states reported sporadic activity; and the District of Columbia, the U.S. Virgin Islands and eight states reported no influenza activity.