Seasonal influenza activity in the United States continues to increase and has been elevated for six weeks now, according to the CDC's FluView report for Week 50, ending Dec. 14, 2019
The percentage of respiratory specimens testing positive for influenza at clinical laboratories increased to 16.3% this week.
Nationally, B/Victoria viruses are most common followed by A(H1N1)pdm09 viruses. The predominant virus varies by region and age group.
Genetic and antigenic characterization and antiviral susceptibility of viruses collected in the U.S. this season are now being reported.
Visits to healthcare providers for influenza-like illness (ILI) increased to 3.9%. ILI has been at or above the national baseline of 2.4% for six weeks. All regions were at or above their baselines.
The number of jurisdictions experiencing high ILI activity increased to 21 this week compared to 12 last week. The number of jurisdictions reporting regional or widespread activity increased to 48 this week from 38 last week.
The overall hospitalization rate for the season increased to 5.5 per 100,000. This is similar to what has been seen at this time during recent seasons.
The percentage of deaths attributed to pneumonia and influenza increased to 5.5% but remains below the epidemic threshold.
Nine new influenza-associated pediatric deaths occurring during the 2019-2020 season were reported to CDC this week. The total for the season is 19.