Friday, January 12, 2018

CDC Briefing & FluView Week #1 - 2018

Flu Now Widespread Across Entire Country


Concurrent with the release of today's FluView Week #1 report  CDC Director Brenda Fitzgerald, M.D. and Dan Jernigan, M.D., M.P.H., Director of the CDC's Influenza Division co-hosted a media briefing on this year's early and aggressive H3N2 dominated flu season. 
Director Fitzgerald opened up the briefing by describing influenza as `widespread and intense' across the nation, emphasized the importance of practicing good flu hygiene (covering coughs, washing hands, staying home when sick), and reminded everyone that it isn't too late to get a flu shot. 
Dr Jernigan handled the bulk of the briefing, where he compared this year's flu season (so far) to being somewhere between the intensity of the 2012-13 and 2014-15 H3N2 seasons; `severe', but too soon to know exactly how severe.

He stressed that while we may be approaching the peak of this year's flu season, we could have another 11 to 13 weeks of flu ahead, and that a second wave of Influenza B or even H1N1, can't be discounted.
While early estimates suggest this year's H3N2 flu vaccine component to only be providing about 30% protection, the numbers against Influenza B and H1N1 are considerably better, making getting the flu shot still a good idea. 
Hospitalizations - particularly among those over 65 - but also in the `Baby Boomer' 50-64 age range, have nearly doubled in the past week.

Dr. Jernigan also stressed the need for high risk, or severely ill flu patients, to receive early and aggressive antiviral treatment.  For a look at those recommendations, see CDC HAN: Seasonal A(H3N2) Flu Activity & Antiviral Treatment of Patients with Influenza.

The briefing (audio & transcript) will be posted on the CDC’s web site, hopefully later today.

Below you'll find some highlights from today's FluView report:

2017-2018 Influenza Season Week 1 ending January 6, 2018

All data are preliminary and may change as more reports are received.


During week 1 (December 31, 2017-January 6, 2018), influenza activity increased in the United States.
  • Viral Surveillance: The most frequently identified influenza virus subtype reported by public health laboratories during week 1 was influenza A(H3). The percentage of respiratory specimens testing positive for influenza in clinical laboratories remained elevated.
  • Pneumonia and Influenza Mortality: The proportion of deaths attributed to pneumonia and influenza (P&I) was at the system-specific epidemic threshold in the National Center for Health Statistics (NCHS) Mortality Surveillance System.
  • Influenza-associated Pediatric Deaths: Seven influenza-associated pediatric deaths were reported.
  • Influenza-associated Hospitalizations: A cumulative rate of 22.7 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 5.8%, which is above the national baseline of 2.2%. All 10 regions reported ILI at or above region-specific baseline levels. New York City and 26 states experienced high ILI activity; Puerto Rico and 10 states experienced moderate ILI activity; the District of Columbia and six states experienced low ILI activity; and eight states experienced minimal ILI activity.
  • Geographic Spread of Influenza:The geographic spread of influenza in 49 states was reported as widespread; Guam and one state reported regional activity; the District of Columbia reported local activity; the U.S. Virgin Islands reported sporadic activity; and Puerto Rico did not report.

Although some back filling of data may change the picture, the following chart showing outpatient ILI visits, suggests the peak of the season may be at hand.  Some seasons decline from this peak more slowly than others, and so we won't know the full story until the flu season has ended.

One last chart (follow the link to read the full report) shows that while H3N2 (in red) is the dominant flu strain being reported, H1N1 and Influenza B are also around.  As H3N2 begins to wane, activity by one or both of these viruses could begin to pick up.