CDC: Flu still rising across U.S.; 16 more pediatric deaths

Despite more reports of influenza B, the vast majority (87.5 percent) of hospitalized infections were associated with influenza A virus, with 12 percent associated with influenza B virus, and only 0.2 percent with influenza A virus and influenza B virus co-infection. H3N2 made up 86.5 percent of hospitalized influenza A infections.

H3N2 is still the dominant strain this season,” Jernigan. “At this pace, the number of flu hospitalization may exceed the 710,000 seen in 2014-2015.”

Yesterday, Canadian researchers released an analysis of mid-season flu vaccine effectiveness, showing that this year’s vaccine was performing dismally against H3N2, offering only about 17 percent protection against that subtype—and even that wasn’t a statistically significant finding.

Older people are especially susceptible to severe H3N2 infections, which contributes to the high rate of hospitalization, Jernigan said.

Among all laboratory samples of the flu surveyed by the CDC this week, 80.2 percent of positive specimens were influenza A, and, of influenza A specimens that were subtyped, 84.3 percent were H3N2. Almost 20 percent (19.8 percent) of samples were influenza B, a strain that becomes more active in the latter half of the flu season.

Neither Jernigan nor Schuchat would speculate whether flu activity was peaking in this, the tenth week of elevated activity. Flu seasons typically last between 11 and 20 weeks.

Increased clinic visits stretch supplies

In another measure of this flu season’s pervasiveness, the number of states experiencing high ILI activity increased from 39 to 42. And, after the CDC reported widespread flu in 49 states for 3 straight weeks, the number this week dropped to 48 states, with Oregon reporting regional activity and Hawaii noting local flu activity.

The percentage of outpatients reporting ILI was 7.1 percent, well above the national baseline of 2.2 percent and up from 6.6 percent last week. In 2009, during the peak of the H1N1 pandemic, that percentage was 7.7 percent. During the 2014-15 season the level peaked at 6.0 percent.

All of the clinic and hospital visits have stretched medical supplies, including saline products used in intravenous bags and medicine preparations. Many of these products are manufactured in Puerto Rico, and the supply was destroyed during this fall’s devastating Hurricane Maria.

Yesterday Scott Gottlieb, MD, the commissioner of the Food and Drug Administration (FDA), issued a statement on these shortages, citing both the severe flu season and Hurricane Maria as the main factors behind the shortage.

“The FDA was able to extend the expiration dates of certain products, including some 500 ml size saline bags, after carefully examining the data submitted by the company to ensure that it meets the FDA’s quality and safety standards,” Gottlieb said. “We continue to encourage companies to submit data to extend expiration dates for drugs in shortage. We’ve also been working with manufacturers such as Baxter and B. Braun to import products into the U.S. from their foreign facilities, including most recently additional products from a Baxter facility in Brazil.”

Gottlieb said there was no nationwide shortage of antiviral drugs, adding that the FDA was closely monitoring national supplies of antivirals as well as flu vaccines.