2018-2019 Influenza Season Week 49 ending December 8, 2018

All data are preliminary and may change as more reports are received.Synopsis:Influenza activity in the United States remained slightly elevated. Influenza A(H1N1)pdm09, influenza A(H3N2), and influenza B viruses continue to co-circulate, with influenza A(H1N1)pdm09 viruses reported most commonly by public health laboratories since September 30, 2018. Below is a summary of the key December 8, 2018:\u2022 Viral Surveillance: Influenza A viruses have predominated in the United States since the beginning of October. The percentage of respiratory specimens testing positive for influenza in clinical laboratories remains low.o Virus Characterization: The majority of influenza viruses characterized antigenically and genetically are similar to the cell-grown reference viruses representing the 2018\u20132019 Northern Hemisphere influenza vaccine viruses.o Antiviral Resistance: All viruses tested show susceptibility to the neuraminidase inhibitors (oseltamivir, zanamivir, and peramivir).\u2022 Influenza-like Illness Surveillance: The proportion of outpatient visits for influenza-like illness (ILI) remained at 2.2%, which is at the national baseline of 2.2%. Five of 10 regions reported ILI at or above their region-specific baseline level.o ILI State Activity Indictor Map: One state experienced high ILI activity; Puerto Rico and four states experienced moderate ILI activity; New York City, the District of Columbia and nine states experienced low ILI activity; and 36 states experienced minimal ILI activity.\u2022 Geographic Spread of Influenza: The geographic spread of influenza in three states was reported as widespread; 10 states reported regional activity; 21 states reported local activity; the District of Columbia, Puerto Rico, the U.S. Virgin Islands and 16 states reported sporadic activity; and Guam did not report.\u2022 Influenza-associated Hospitalizations A cumulative rate of 1.9 laboratory-confirmed influenza-associated hospitalizations per 100,000 population was reported.\u2022 Pneumonia and Influenza Mortality: The proportion of deaths attributed to pneumonia and influenza (P&I) was below the system-specific epidemic threshold in the National Center for Health Statistics (NCHS) Mortality Surveillance System.\u2022 Influenza-associated Pediatric Deaths: One influenza-associated pediatric death was reported to CDC for week 49.2018713