Citi analyst: Flu activity up year over year in early December

NEW YORK — Predictions of a more active flu season are coming true as temperature differences have helped drive flu activity, a Citibank financial analyst wrote.

In a letter to investors, Citi Research analyst Deborah Weinswig wrote that influenza virus activity in the week ended Dec. 8 increased year over year for the ninth consecutive time this season and increased significantly compared with last week — up 28.3% compared with last week's 20.7%.

Meanwhile, natural temperatures during the week were significantly warmer compared with the same period last year, but cooler year-over-year temperatures in the prior four weeks helped drive increased flu activity.

Overall, the Midwest, Southeast and Central parts of the country experienced the highest flu activity during the week. The U.S. Outpatient Influenza-like Illness Surveillance Network reported that 2.8% of patient visits during the week were due to influenza-like illness, above the national baseline of 2.2% and the highest percentage this season. Activity was up by 0.9% from last week and above the 1.2% reported during the same period last year.

The report noted that while Walgreens reported a 10-bps negative impact due to lower cough, cold and flu incidence, Weinswig said the chain lost flu shot share in a competitive environment, while CVS reported that front-end same-store sales experienced a positive effect from flu-related sales.

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