Influenza B officially became the most frequently reported flu strain during the week of March 26, according to the most recent FluView report from the CDC.
More than half (55.9 percent) of specimens tested in public health laboratories were influenza B, while the remaining 44.1 percent were influenza A during the week of March 26. In tests performed by clinical laboratories during that time period, 60.9 percent were influenza B.
Despite influenza B's late-season surge, flu activity is on the decline. For instance, the proportion of deaths attributed to pneumonia and influenza was below the epidemic threshold, and the rate of hospitalizations fell to 1.9 percent, down from 2.7 percent the week prior.
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The percent of outpatient visits for flu-like illness also fell to 2.9 percent (from 3.2 percent the week prior), but remained above the national baseline of 2.2 percent.
Nine states (Alabama, Georgia, Kentucky, New York, North Carolina, Rhode Island, South Carolina, Tennessee and Virginia) still have high influenza-like illness activity, while 37 states experienced minimal such activity.