Brisk US flu activity continues as COVID indicators drop further

young woman sick in bed


The nation's flu activity remained elevated last week, with an increase in test positivity, as levels of two other respiratory viruses—COVID-19 and respiratory syncytial virus (RSV)—continued their steady declines, the Centers for Disease Control and Prevention (CDC) said in updates today.

In its respiratory virus snapshot of all three diseases, the CDC said illness levels remain elevated in many parts of the country. Sixteen jurisdictions are reporting high or very high activity, down from 22 the previous week.

RSV indicators are declining in all parts of the country, with levels now below the epidemic threshold in 6 of 10 regions.

Flu hot spots in Central, Midwestern states

Flu activity ebbs a bit in the first weeks of January, but has been on the rebound since February, mainly driven by rises in regional activity. States in the Central and Midwest regions are currently reporting the highest activity.

The percentage of respiratory tests that were positive for flu last week at clinical labs rose to 15.4%, and labs are seeing roughly equal proportions of the 2009 H1N1 and H3N2 strains of influenza A and influenza B, the CDC said in its latest weekly FluView update.

Other indicators showed declines, including outpatient visits for flulike illness, which are at 3.7% and above the national baseline. Flu hospitalizations also declined last week, continuing a downward trend since January. Seniors make up the highest proportion of flu hospitalizations, though levels are elevated for all age-groups. Meanwhile, emergency department visits for flu are highest in children.

Overall deaths were up slightly, and the CDC reported 13 more pediatric flu deaths, raising the season's total to 116. The deaths occurred from late December through early March. Nine deaths were due to influenza A, three from influenza A, and one from a coinfection involving 2009 H1N1 and influenza B.

The CDC also reported 2 more pediatric flu deaths from the 2022-23 season, putting that total at 184.

COVID wastewater detections at moderate level

In COVID data updates today, the CDC reported declines in both of its severity markers. Hospitalizations declined 13.5% from the previous week, and deaths dropped 4.8% over the same period.

Among early indicators, national test positivity declined 1.5% compared to a week ago and is at 5.2% nationally. Emergency department visits dropped 24.8% and are still highest in children younger than 12 months old and in seniors.

Wastewater SARS-CoV-2 detections, considered another early marker, remain at the moderate level. Levels are still highest in the South, but, even there, levels are dropping steadily.

In variant proportion updates, JN.1 remained dominant, with its offshoot JN.1.13 rising to 9.5% from 4.6% the previous week.

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