While the percentage of respiratory specimens testing positive for flu is on the decline and influenza A remains the most frequently identified flu strain, instances of influenza B infections seem to be on the rise, according to the CDC's most recent FluView.
The percent of positive influenza B tests has been on the rise for the last two weeks reported, while the percent of specimens testing positive for influenza A has decreased for the last five weeks. For the week ending March 18, 9.49 percent of specimens tested positive for influenza A and 8.4 percent were influenza B, compared to 11.54 percent and 7.43 percent, respectively, the week before.
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According to the Center for Infectious Disease Research and Policy at the University of Minnesota in Minneapolis, the late-season influenza B surge is "typical".
Overall, flu activity decreased during the week ending March 18, but is still elevated — the proportion of outpatient visits for influenza-like illness remained above the national baseline, and the proportion of deaths attributed to pneumonia and influenza remained above the epidemic threshold as well.
More people this flu season have been hospitalized than in the 2015-16 season: This season, the overall hospitalization rate is 50.4 per 100,000 people, while last season at this time the overall hospitalization rate was 20.6 per 100,000 people.