Influenza activity increased again during the week ending December 7 (week 49), according to a report from the Centers for Disease Control and Prevention (CDC).
Influenza activity has now been at or above the national baseline for 5 weeks and almost half of the country is experiencing widespread illness. Influenza activity is at or above the baseline in all 10 regions of the United States.
CDC estimates that at least 2.6 million illnesses, 23,000 hospitalizations, and at least 1300 deaths have resulted from influenza so far this season.
One indicator — the proportion of outpatient visits for influenza-like illness (ILI) — fell slightly to 3.2% from 3.5% the week before, a decrease that was likely a result of the Thanksgiving holiday, the CDC explains.
Similar dips have occurred at this point during previous influenza seasons as well. Last season at this time, the proportion of outpatient visits was 2.2% and did not reach current levels until week 51, when it was 3.3%.
Nationally, the predominant strain is B/Victoria, followed by A(H1N1)pdm09 and A(H3N2). It is unusual to have B/Victoria as the predominant strain this early in the season, according to the CDC. Influenza A(H1N1) viruses are also increasing. Last season at this time, influenza A viruses predominated.
Influenza activity was high in Puerto Rico and 11 states (AL, AR, GA, MS, NE, NM, SC, TN, TX, VA, and WA) and moderate in New York City and 11 states (AZ, CO, CT, HI, KY, MD, MN, NV, NJ, OK, and OR). The rest of the country had low or minimal activity.
Influenza activity was "widespread" in 23 states (AL, AZ, CA, CT, GA, ID, IN, KY, LA, MD, MA, NE, NV, NM, NY, NC, OR, PA, SC, TN, TX, VA, WA) and "regional" in Puerto Rico and 14 states (AK, CO, FL, IL, MI, MN, MS, MT, NJ, OH, OK, RI, UT, and WI). Activity was local or sporadic in the remaining jurisdictions.
The cumulative rate of laboratory-confirmed hospitalizations for influenza-like illness activity rose from 2.9 per 100,000 population the previous week to 3.9. Rates were highest among those aged 65 years and older (9.4 per 100,000) and those younger than 5 years (7.5 per 100,000). The rate was 4.1 per 100,000 for adults aged 50 to 64 years.
On a positive note, more than 99% of all influenza viruses tested this season responded to the four influenza antiviral drugs approved by the FDA and recommended in the United States for this season.
CDC officials remind the public that there is still time to get vaccinated against influenza.
Cite this: Influenza Sickens Millions Across US, at Least 1300 Deaths: CDC - Medscape - Dec 16, 2019.