Seasonal influenza activity in the United States has been elevated for five weeks and continues to increase, according to the CDC's FluView report for Week 49, ending Dec. 7, 2019.

11.3% of respiratory specimens tested by clinical laboratories were positive for influenza viruses. This is higher than the previous week.

Nationally, B/Victoria viruses are most common followed by A(H1N1)pdm09 and A(H3N2) 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.

3.2% of visits to healthcare providers were for influenza-like illness (ILI). ILI has been at or above the national baseline of 2.4% for five weeks. All regions were at or above their baselines.

The number of jurisdictions experiencing high ILI activity decreased to 12 this week compared to 13 last week. In addition, 12 jurisdictions had moderate activity compared to 15 last week.

The number of jurisdictions reporting regional or widespread activity increased to 38 this week from 30 last week.

The overall hospitalization rate for the season is 3.9 per 100,000. This is similar to what has been seen at this time during other recent seasons.

5.0% of deaths were attributed to pneumonia and influenza (P&I). This is below the epidemic threshold of 6.5%.

Four new influenza-associated pediatric deaths occurring during the 2019-2020 season were reported to CDC this week. The total for the season is 10.

Source: CDC