CDC: Widespread flu leads to 7 new deaths in kids

Sick child
Sick child with fever

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Flu activity in the United States continued to rise last week, with most indicators increasing and seven more pediatric flu deaths reported, the US Centers for Disease Control and Prevention (CDC) said today in its regular update.

Clinic visits rise, H3N2 still dominates

The percentage of clinic visits for flulike illness rose to 3.9% nationally, up from 3.4% the week before. The United States has been above the baseline for that marker for 7 consecutive weeks now.

Meanwhile, the percentage of respiratory swabs that were positive for flu was at 18%, down slightly from 18.4% the previous week. Influenza A accounted for 88% of the detections, and, among subtyped influenza A samples, H3N2 remained the dominant strain, making up 94% of the total.

Of H3N2 viruses that have been antigenically characterized since Oct 1, 95.6% belong to the Hong Kong-like strain included in this season's vaccines. So far no influenza A or B viruses tested by the CDC have shown resistance to three neuraminidase inhibitors, the most commonly used antivirals against flu.

Hospitalizations, pediatric flu deaths up

Hospitalization rates for flu also took another jump, rising to 20.3 per 100,000 population, with the highest level seen in people age 65 and older, a group typically hard hit by the H3N2 subtype. For seniors, the rate rose to 94.8 per 100,000 population.

The week before, hospitalizations were at 15.4 and 72.2 per 100,000 in the general population and in seniors, respectively.

Seven pediatric flu deaths were reported last week, lifting the season's total to 15 for the season. All occurred in January, with 3 linked to H3N2, 3 to unsubtyped influenza A viruses, and 1 to influenza B. Since the CDC started recording pediatric flu deaths in 2004, the season total has ranged from a low of 37 to a high of 171.

The CDC wasn't able to update its marker showing the percentage of overall deaths from pneumonia and flu last week because of data processing problems, but as of Jan 7 the number was slightly above the epidemic threshold.

The CDC said the number of locations reporting widespread flu rose to 40 states and Puerto Rico, reflecting an increase of 3 states from the week before. The number of states reporting high activity—another marker of clinic visits for flu—rose to 15 states and New York City, 5 more than the previous week.

Flu in Europe still elevated

In Europe, where flu activity this season began earlier than usual, levels are still elevated and stable, though activity decreased last week for some countries, according to the latest joint update from the European Centre for Disease Prevention and Control and the World Health Organization Regional Office for Europe.

As in the United States, H3N2 is the dominant strain in Europe, which is also reporting that older people account for the largest portion of flu hospitalizations. Most circulating H3N2 viruses are antigenically similar to the vaccine strain. And so far testing for neuraminidase inhibitor resistance has found only one virus that has shown reduce susceptibility, to zanamivir.

See also:

Feb 3 CDC FluView update

Feb 3 CDC flu situation update

Flu News Europe update

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