Influenza activity remains elevated across much of the nation, and while some regions have seen some reduction in flu reports, this week’s CDC FluView report once again shows the P&I (Pneumonia & Influenza) Mortality rate well above the epidemic threshold at 9.1%.
Hospitalizations – particularly for those over the age of 65 – have soared to 176.1 per 100,000 – double the maximum hit last year and nearly as high as we saw in the particularly harsh 2012-13 season. Additionally, 11 more pediatric flu-related deaths were reported.
Nearly all of the flu in the country is A/H3N2, and roughly 2/3rds of those samples tested continue to be `mismatched’ to this year’s vaccine strain. With weeks remaining in this year’s flu season, the CDC continues to advise that the Prompt Use of Antivirals is Key this Flu Season.
A few excerpts from today’s report.
All data are preliminary and may change as more reports are received.
During week 2 (January 11-17, 2015), influenza activity remained elevated in the United States.
- Viral Surveillance: Of 26,205 specimens tested and reported by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories during week 2, 5,104 (19.5%) were positive for influenza.
- Pneumonia and Influenza Mortality: The proportion of deaths attributed to pneumonia and influenza (P&I) was above the epidemic threshold.
- Influenza-associated Pediatric Deaths: Eleven influenza-associated pediatric deaths were reported.
- Influenza-associated Hospitalizations: A cumulative rate for the season of 36.3 laboratory-confirmed influenza-associated hospitalizations per 100,000 population was reported.
- Outpatient Illness Surveillance: The proportion of outpatient visits for influenza-like illness (ILI) was 4.5%, above the national baseline of 2.0%. All 10 regions reported ILI at or above region-specific baseline levels. Puerto Rico and 23 states experienced high ILI activity; New York City and 10 states experienced moderate ILI activity; 10 states experienced low ILI activity; seven states experienced minimal ILI activity; and the District of Columbia had insufficient data.
- Geographic Spread of Influenza: The geographic spread of influenza in 44 states was reported as widespread; Guam, Puerto Rico, the U.S. Virgin Islands, and five states reported regional activity; and the District of Columbia and one state reported local activity.
Eleven influenza-associated pediatric deaths were reported to CDC during week 2. Three deaths were associated with an influenza A (H3) virus and occurred during weeks 51, 53, and 1 (weeks ending December 20, 2014, January 3, and January 10, 2015, respectively). Eight deaths were associated with an influenza A virus for which no subtyping was performed and occurred during weeks 51, 52, 53, 1, and 2 (weeks ending December 20, December 27, 2014, and January 3, January 10, and January 17, 2015, respectively).
A total of 56 influenza-associated deaths have been reported during the 2014-2015 season from New York City  and 23 states (Arizona , Colorado , Florida , Georgia , Indiana , Iowa , Kansas , Kentucky , Louisiana , Michigan , Minnesota , Missouri , North Carolina , Nevada , Ohio , Oklahoma , Pennsylvania , South Carolina , South Dakota , Tennessee , Texas , Virginia , and Wisconsin ).
Additional data can be found at: http://gis.cdc.gov/GRASP/Fluview/PedFluDeath.html.
Between October 1, 2014 and January 17, 2015, 9,926 laboratory-confirmed influenza-associated hospitalizations were reported. The overall hospitalization rate was 36.3 per 100,000 population. The highest rate of hospitalization was among adults aged ≥65 years (176.1 per 100,000 population), followed by children aged 0-4 years (34.5 per 100,000 population). Among all hospitalizations, 9,597 (96.8%) were associated with influenza A, 244 (2.5%) with influenza B, 25 (0.2%) with influenza A and B co-infection, and 52 (0.5%) had no virus type information. Among those with influenza A subtype information, 2,623 (99.7%) were A(H3N2) virus and seven (0.3%) were A(H1N1)pdm09.
Clinical findings are preliminary and based on 1,319 (13.3%) cases with complete medical chart abstraction. The majority (93.9%) of hospitalized adults had at least one reported underlying medical condition; the most commonly reported were cardiovascular disease, metabolic disorders, and obesity. There were 196 hospitalized children with complete medical chart abstraction, 83 (42.3%) had no identified underlying medical conditions. The most commonly reported underlying medical conditions among pediatric patients were asthma, obesity, neurologic disorders, and immune suppression. Among the 146 hospitalized women of childbearing age (15-44 years), 40 were pregnant.
Additional FluSurv-NET data can be found at: http://gis.cdc.gov/GRASP/Fluview/FluHospRates.html and http://gis.cdc.gov/grasp/fluview/FluHospChars.html.
Despite its reduced effectiveness, the CDC continues to recommend that people get the flu shot – partially because it may provide some modicum of protection against this drifted flu strain, and partly because we often see a wave of Influenza B late in the flu season, and the shot can help protect against that virus.
Beyond that, practicing good flu hygiene; Staying home when sick, washing your hands, covering your coughs, and disposing of your tissues properly are all important habits to maintain during this flu season.