Flu widespread in 43 states; 5 more fatal cases in kids

nasal swab
nasal swab

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US flu activity jumped higher last week, with widespread activity reported in 43 states and five more pediatric flu deaths reported.

In its weekly update today, the US Centers for Disease Control and Prevention (CDC) reported the marker that tracks clinic visits for flulike illness has now been above the national baseline for eight consecutive weeks.

In one sign that that the flu season is heading into its later months, the number of influenza B detections increased slightly, a development also reported by European officials.

Doctor's offices still busy with flu patients

The percentage of clinic visits for flulike illness climbed to 4.8%, up from 3.9% the week before. Respiratory specimens that were positive for flu rose to their highest percentage yet, at 20.9, up from 18% the previous week.

Influenza A accounted for 87.7% of the detections at clinical labs, while the influenza B detections from clinical labs rose to 12.3%. H3N2 is still the dominant influenza A strain, making up 97.6% of subtyped strains.

So far most circulating H3N2 strains are similar to the strain in the vaccine, and so far, none of the tested viruses have shown any resistance to neuraminidase inhibitors.

The CDC's flu maps show that flu is now widespread in 43 states and Puerto Rico, an increase of three from the week before. High flu activity, another indicator of clinic visits for flu, was reported for 23 states and New York City, reflecting an increase of 8 states.

Five more pediatric flu deaths

Five more pediatric flu deaths were reported, boosting the season's total to 20 for the current season. Since the CDC started tracking pediatric flu deaths in the 2004-2005 season, totals have ranged from a low of 37 to a high of 171.

Among the latest deaths, three were from H3N2, one was from 2009 H1N1, and one was from influenza B. All of them occurred in January.

Overall deaths from pneumonia and flu are at 7.9%, putting them slightly above the epidemic threshold.

Hospitalizations for flu rose again, with the overall rate rising to 24.3 per 100,000 population. For seniors, a group typically hit hard by H3N2, the level is much higher at 113.5 per 100,000 population. CDC said hospitalizations for flu are running lower than for the 2014-2015 season, another year when H3N2 also predominated, though the circulating strain that year was a poor match with the strain in the vaccine.

Europe and global flu updates

In Europe, which saw an earlier than usual start to the flu season, activity is still elevated, with 28 of 43 countries still reporting very high intensity, according to a joint weekly update from the European Centre for Disease Prevention and Control and the World Health Organization Regional Office for Europe.

The percentage of respiratory specimens that tested positive for flu dropped from about 52% to 45%, compared to the previous week. Though H3N2 is still the dominant strain, the European region is also starting to see the usual rise in influenza B detections, which rose slightly last week.

In a regular snapshot of global flu activity, the WHO earlier this week said that flu in temperate regions of the Northern Hemisphere continues to increase, with many countries in East Asia and Europe passing their seasonal thresholds earlier than usual.

Influenza A viruses made up 95% of the detections. H3N2 is still the dominant strain globally.

See also:

Feb 10 CDC FluView update

Feb 10 CDC flu situation update

Flu News Europe update

Feb 6 WHO global flu update

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