During week 1 (December 31, 2017-January 6, 2018), influenza activity increased in the United States.\u2022 Viral Surveillance: The most frequently identified influenza virus subtype reported by public health laboratories during week 1 was influenza A(H3). The percentage of respiratory specimens testing positive for influenza in clinical laboratories remained elevated.\u2022 Pneumonia and Influenza Mortality: The proportion of deaths attributed to pneumonia and influenza (P&I) was at the system-specific epidemic threshold in the National Center for Health Statistics (NCHS) Mortality Surveillance System.\u2022 Influenza-associated Pediatric Deaths: Seven influenza-associated pediatric deaths were reported.\u2022 Influenza-associated Hospital...