Influenza Update Week Ending 4-21-2018

Influenza Update Week Ending 4-21-2018

Influenza (FLU) Update for Week #16 Week Ending 4-21-18

Continued good news about Flu but there are still a couple of indicators that have yet to fall, namely, the rate of hospitalizations from flu, as well as the number of pediatric deaths.  However, for the third time in-a-row since the third week in November, influenza activity (ILI) was below the national baseline and the number of flu cases once again decreased.

This chart, copied from the CDC Weekly U.S. Influenza Surveillance Report, provides an excellent way of comparing this flu season with others, starting from 2009-2010.  The silver line represents the 2009 Pandemic of H1N1 and the red line outlines the current 2017-18 Flu Season.  The legend to the right of the graph lists the other seasons.

A quick glance at the graphs for Percentages of Visits for ILI and Pneumonia and Influenza Mortality Surveillance, gives a pictorial presentation of the severity of this flu season.

FirstWatch RIN (Reginal Influenza Network) Alerts occurred rarely, which correlated with CDC reports of continued decreased activity. 

For the most recently reported week ending April 21, 2018, the CDC reported:
–ILI visits to clinics and other non-hospital facilities decreased again and was again below the baseline of 2.2% at 1.7% (was 1.8% last week).  For the second week in a row, only Region 1 (Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island and Vermont) was listed as “ELEVATED.  All other Regions were listed as “NORMAL”.
–Flu cases (documented by positive flu tests) decreased again but remained elevated with widespread flu reported in 4 states.  “NO ACTIVITY” was reported by Alabama and Mississippi.  Clinical lab testing for influenza was positive for flu in 8.9% of the total tests (compared with 10.9% last week). Influenza B remained the dominant flu type with 69.4% of the positive flu tests reported.  The remainder of the positive flu tests were Influenza A at 30.6%.

The CDC provides an interactive U.S. map that will link to each state’s public health authorities, ILI and flu information and processes, as well as other diseases and public health topics. 
Find it at this site:

For Influenza-Like Illness (ILI)
High ILI Activity (1 state):  Arizona
Moderate ILI Activity (2 states):  Alaska and South Dakota,
Low Activity (6 states):  Georgia, Indiana, Kentucky, Massachusetts, Rhode Island and Virginia
Minimal Activity (New York City, Washington D.C., Puerto Rico & 41 states):  Alabama, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Hawaii, Idaho, Illinois, Iowa, Kansas, Louisiana, Maine, Maryland, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, South Carolina, Tennessee, Texas, Utah, Vermont, Washington, West Virginia, Wisconsin and Wyoming

For Flu (positive flu tests)
Widespread Activity (4 states):  Connecticut, Delaware, Massachusetts and New York
Regional Activity (Guam, Puerto Rico & 9 states):  Arizona, Kentucky, Maine, New Hampshire, New Jersey, Ohio, Rhode Island, Utah, and Wisconsin
Local Activity (25 states):  Alaska, California, Colorado, Florida, Georgia, Hawaii, Illinois, Iowa, Kansas, Maryland, Michigan, Minnesota, Missouri, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, Pennsylvania, South Carolina, South Dakota, Vermont, Virginia, Washington and West Virginia
Sporadic Activity (Washington D.C., U.S. Virgin Islands & 10 states):  Arkansas, Idaho, Indiana, Louisiana, Nevada, North Carolina, Oregon, Tennessee, Texas and Wyoming
No Activity (2 states):  Alabama and Mississippi

Other Data:
Hospitalizations from Flu since Oct. 1, 2017 have had a cumulative rate of 105.3 per 100,000. The cumulative and each age group again reported higher rates than those of the previous week and higher than at the same point in the “Severe” 2014-15 Flu Season.  Specifically, those 65 years and older with 454.3 per 100,000 (446.4/100,000 last week); ages 50-64 at 114.4 per 100,000 (112.8/100,000); and ages 0-4 at 73.5 per 100,000 (72.7/100,000).  The percentage of pregnant women from the females of childbearing age group (15-44) who were hospitalized were at/near 30% (30.8%), another slight decrease, after being around 25% for the peak weeks of the flu season.
Death rates for pneumonia & influenza in adults decreased slightly from last week to 6.9% (7.1% last week) which, for the fourth week in a row, fell below the epidemic threshold of 7.2% for Week #14, ending 4/7/18.
There were 4 more pediatric deaths from Flu reported in Week #16, for a total of 160 for this flu season; it has surpassed the total numbers of death for the severe flu season of 2014-15.

Flu in Canada and Europe for Week #15:
According to the Public Health Agency of Canada (PHAC), most influenza activity indicators decreased although some areas are still reporting localized activity.  All flu indicators decreased or remained the same.  Positive tests for flu remained greater for Influenza A than B.  The majority of the diagnosed flu cases, hospitalizations, and deaths remained in those 65 years and older.
For more info see:

The European Center for Disease Prevention & Control (ECDC) reported that flu activity was at levels seen between flu seasons except in one country.  Lab tests from PCPs were positive for flu 12% of the time with more Influenza A than B currently co-circulating; the majority of the cases were Influenza A.
For more info see:

Download the Full Update, and Read EMS Specific Recommendations

See this link for more details, including charts, graphs and maps.

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