Avian Flu Diary: FluView Week 51: Influenza `Increased Sharply' Across The Nation

#13,013

As widespread, and as early, as this week's FluView report makes this year's flu season look - given the inevitable delays in reporting (exacerbated, no doubt, by the Holidays) - things are likely worse than it appears.

There are also ongoing problems collecting data on the Influenza P&I mortality numbers, which are only `current' as of Dec 9th. Officially we remain below the `epidemic threshold', but those numbers are subject to revision as more data is processed.

In any event, here are the highlights from this week's report.

2017-2018 Influenza Season Week 51 ending December 23, 2017

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

Synopsis:
During week 51 (December 17-23, 2017), influenza activity increased sharply in the United States.

Viral Surveillance: The most frequently identified influenza virus subtype reported by public health laboratories during week 51 was influenza A(H3). The percentage of respiratory specimens testing positive for influenza in clinical laboratories increased.

Pneumonia and Influenza Mortality: The proportion of deaths attributed to pneumonia and influenza (P&I) was below the system-specific epidemic threshold in the National Center for Health Statistics (NCHS) Mortality Surveillance System.

Influenza-associated Pediatric Deaths: Three influenza-associated pediatric deaths were reported.

Influenza-associated Hospitalizations: A cumulative rate of 8.7 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 5.0%, which is above the national baseline of 2.2%. All 10 regions reported ILI at or above region-specific baseline levels. Twenty-one states experienced high ILI activity; New York City and five states experienced moderate ILI activity; eight states experienced low ILI activity; 14 states experienced minimal ILI activity; and the District of Columbia, Puerto Rico and two states had insufficient data.

Geographic Spread of Influenza:The geographic spread of influenza in 36 states was reported as widespread; Puerto Rico and 13 states reported regional activity; one state reported local activity; and the District of Columbia, the U.S. Virgin Islands, and Guam did not report.

Perhaps the most telling chart provided is the following, showing the percentage of doctors visits for ILI, which has very nearly matched the February peak from last year's flu season. And it continues to climb like a homesick angel.