Influenza Update Week Ending 3-3-2018Jenny Abercrombie
Influenza (FLU) Update for Week #9 Week Ending 3-3-18 Although Flu and ILI are still fairly widespread and above the national baseline, respectively, Week #9 was the third week with significant decreases in most flu indicators. The peak of the season was when ILI was at a high of 7.5%, which occurred during Week #5, ending 2/3/18. The one indicator that showed increases in all the reported ages was in hospitalizations for Flu and Pneumonia. This indicator should begin to report decreases within the next few weeks.
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 showed another slight decrease in occurrence, which correlated with CDC reports. Some of these alerts are likely related to the still increasing number of individuals being hospitalized.
For the most recently reported week ending March 3, 2018, the CDC reported:
–ILI visits to clinics and other non-hospital facilities decreased again but remained elevated at 3.7% (was 5% last week), and was at or above the national baseline of 2.2% for the 15th week in a row. All 10 Regions again reported ILI at or above their region-specific baselines with 48 of 54 jurisdictions reporting ELEVATED. On average, for the past five flu seasons, the ILI has remained at/above baseline for 16 weeks, suggesting elevated activity will continue well into March.
–Flu cases (documented by positive Flu tests) also decreased but remained elevated with widespread flu reported in 34 states. Clinical lab testing for influenza was positive for Flu in 17.7% of the total tests (compared with 21.6% last week). This decreasing trend should continue.
–Influenza B became the dominant Flu type with 50.1% of the positive flu tests reported (48.4% last week). The remainder of the Flu tests were Influenza A at a very close 49.9% (51.6% last week), with the subtype H3N2 with 67.9% of the time (80.2% last week) and 28.5% (19.8% last week) as A (H1N1)pdm09.
–Vaccine Coverage: the majority of the flu viruses collected this season are well matched to the seasonal vaccine offered, although less so, with H3N2; the remaining A Flu, H1N1, and the B Flus have a better response. Overall, vaccine effectiveness is still less than hoped for, but it appears that the flu vaccine decreased the likelihood of seeing a health care practitioner because of Flu about 36% this season, with the percentage increasing as H1N1 and Influenza B flus dominate. It is still recommended that anyone who has not received flu vaccine get it ASAP, since even it if doesn’t prevent the flu in everyone, the length and severity of the Flu would likely be lessened as well the time when a person is able to infect someone else (called shedding).
The CDC provides an interactive U.S. map that will link to teach state’s public health authorities, ILI and Flu information and processes, as well as other diseases and public health topics. This site includes a tremendous amount of information at the State, and even Local, level.
Find it at this site: https://www.cdc.gov/flu/weekly/usmap.htm
–For Influenza-Like Illness (ILI)
High ILI Activity (New York City and 21 states): Alaska, Arizona, Arkansas, Georgia, Indiana, Kansas, Kentucky, Massachusetts, Michigan, Missouri, Nebraska, New Jersey, New Mexico, New York, Pennsylvania, South Carolina, South Dakota, Texas, Vermont, Virginia and Wyoming
Moderate ILI Activity (15 states): Alabama, California, Colorado, Connecticut, Louisiana, Maryland, Minnesota, Mississippi, New Hampshire, North Carolina, Oklahoma, Oregon, Rhode Island, West Virginia and Wisconsin
Low Activity (Washington D.C., Puerto Rico and 5 states): Hawaii, Illinois, Montana, Nevada and Washington
Minimal Activity (9 states): Delaware, Florida, Idaho, Iowa, Maine, North Dakota, Ohio, Tennessee and Utah
–For Flu (positive Flu tests)
Widespread Activity (Puerto Rico and 34 states): Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Georgia, Idaho, Indiana, Iowa, Kansas, Maine, Maryland, Massachusetts, Michigan, Missouri, Montana, Nebraska, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Dakota, Virginia, Washington, Wisconsin and Wyoming
Regional Activity (Guam and 12 states): Alabama, Alaska, Illinois, Kentucky, Louisiana, Minnesota, Mississippi, Nevada, South Carolina, Tennessee, Texas and Utah
Local Activity (Washington D.C. and 4 states): Hawaii, Oregon, Vermont and West Virginia
No Activity: U.S. Virgin Islands
Hospitalizations from Flu since Oct. 1, 2017 have had a cumulative rate of 86.3 per 100,000. The cumulative and each age group reported significantly higher rates than those of the previous week and higher than the same point in the “Severe” 2014-15 flu season. Specifically, those 65 years and older with 370.6/100,000; ages 50-64 at 93.6/100,000; and ages 0-4 at 62.5/100,000. Also, after hovering around the 25% mark for many weeks, the percentage of pregnant women from the group of females of childbearing age (15-44) who were hospitalized, rose to 30.4%.
Death rates for pneumonia & influenza in adults decreased again to 8.8% (9.0% last week) but remained above the epidemic threshold of 7.4%. Note: death reports often aren’t submitted for data purposes in the same time frame as Flu and ILI cases are, so they lag behind most other Flu reporting. These numbers are from Week #7, ending 2/17/18.
There were 5 more pediatric deaths from Flu reported in Week #9, for a total of 119 this Flu season.
–Flu in Canada and Europe for Week #9:
According to the Public Health Agency of Canada (PHAC), although Flu activity remained high, data surveillance indicates that the Flu season peaked during Week #7. Flu activity is decreasing slowly in many areas of the country. Influenza B cases continue to be larger than those of Influenza A. Most of the diagnosed flu cases, hospitalizations, and deaths remained in those 65 years and older.
For more info see: https://www.canada.ca/en/public-health/services/diseases/flu-influenza.html
According to the European Center for Disease Prevention & Control (ECDC), Flu remains widespread in the Region; some countries are experiencing a slow start to their season. Those with cold weather may have a more severe Flu season. Influenzas A & B are co-circulating with more B than A found. For those tested for flu at PCPs, 49% tested positive.
For more info see: http://www.flunewseurope.org/
See this link for more details, including charts, graphs and maps. https://www.cdc.gov/flu/weekly/