After three weeks of decline, the percent of samples testing positive for influenza in clinical laboratories shot up in the last reported week, from 17.84 percent testing positive to 20.14 percent testing positive, according to the most recent FluView report from the CDC.
For the first time this season, the majority of specimens tested in clinical labs (52.7 percent) were influenza B during the week of March 19, instead of previously dominant influenza A.
However, influenza A remained the dominant strain in specimens tested in public health labs (53.2 percent).
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Additionally, the proportion of deaths attributed to pneumonia and influenza remained above the epidemic threshold during the week of March 19, and the proportion of outpatient visits for influenza-like illness sat at 3.2 percent, higher than the baseline of 2.2 percent.
Flu activity remains widespread in 31 states, mostly on the East Coast and in the Midwest. Twelve states, including Texas and California, reported regional activity, and five states and the District of Columbia reported and local activity during the week of March 19. Only two states — Hawaii and Utah — reported sporadic activity.
Six flu-associated pediatric deaths were reported during the week of March 19, bringing the total number of such deaths so far this flu season to 61, still lower than last season's 89 deaths.