CDC Flu Update: Activity Continues to be Sporadic

According to this week’s FluView report, seasonal influenza activity is low overall across the United States.  Forty states, the District of Columbia, and the U.S. Virgin Islands reported sporadic influenza activity and only Guam and two states reported local activity. Despite low flu activity, the first pediatric death occurring during the 2018-2019 season also is being reported this week.

Flu vaccine is the best way to protect against influenza and its potentially serious compilations. There are many benefits to vaccination, including reducing the risk of flu illness, doctor’s visits, hospitalization, and even death in children. For the 2018-2019 influenza season, there is updated flu vaccine and many vaccine options, including nasal spray vaccine. CDC recommends that everyone 6 months and older get vaccinated by the end of October. Below is a summary of the key flu indicators for the week ending Oct. 13, 2018:

Influenza-like Illness Surveillance: For the week ending October 13 (week 41), the proportion of people seeing their health care provider for influenza-like illness (ILI) was 1.4% and is below the national baseline of 2.2%. All 10 regions reported a proportion of outpatient visits for ILI below their region-specific baseline levels. Additional ILINet data, including national, regional, and select state-level data for the current and previous seasons, can be found at http://gis.cdc.gov/grasp/fluview/fluportaldashboard.html.

Influenza-like Illness State Activity Indicator Map: New York City, the District of Columbia, Puerto Rico, and 49 states experienced minimal ILI activity. Data were insufficient to calculate an ILI activity level from one state (New York). Additional data, including data for previous seasons, can be found at https://gis.cdc.gov/grasp/fluview/main.html.

Geographic Spread of Influenza Viruses: Local influenza activity was reported by Guam and 2 states (Massachusetts and North Dakota). Sporadic activity was reported by the District of Columbia, the U.S. Virgin Islands and 40 states (Alabama, Alaska, Arizona, Arkansas, California, Connecticut, Delaware, Florida, Georgia, Hawaii, Idaho, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Michigan, Minnesota, Missouri, Montana, Nevada, New Hampshire, New Jersey, New Mexico, New York, Ohio, Oklahoma, Oregon, Pennsylvania, South Carolina, South Dakota, Texas, Utah, Vermont, Washington, West Virginia, Wisconsin and Wyoming). No influenza activity was reported by the 8 states (Colorado, Illinois, Mississippi, Nebraska, North Carolina, Rhode Island, Tennessee, and Virginia). Puerto Rico did not report. Geographic spread data show how many areas within a state or territory are seeing flu activity. Additional data are available at: https://gis.cdc.gov/grasp/fluview/FluView8.html.

Flu-Associated Hospitalizations:
Reporting of influenza-associated hospitalization data from the Influenza Hospitalization Surveillance Network (FluSurv-NET) for the 2018-2019 influenza season will begin later this season. Additional data, including hospitalization rates during previous influenza seasons, can be found at http://gis.cdc.gov/GRASP/Fluview/FluHospRates.html and http://gis.cdc.gov/grasp/fluview/FluHospChars.html.

Mortality Surveillance:
The proportion of deaths attributed to pneumonia and influenza (P&I) was 5.6% during the week ending October 6, 2018 (week 40). This percentage is below the epidemic threshold of 5.8% for week 40 in the National Center for Health Statistics (NCHS) Mortality Surveillance System.
Additional P&I mortality data for current and past seasons and by geography (national, HHS region, or state) are available at https://gis.cdc.gov/grasp/fluview/mortality.html.

Pediatric Deaths:
The first influenza-associated pediatric death that occurred during the 2018-2019 season was reported to CDC during week 41. This death was associated with an influenza A virus for which no subtyping was performed. Additional information on influenza-associated pediatric deaths including basic demographics, underlying conditions, bacterial co-infections, and place of death for the current and past seasons, pediatric deaths is available on FluView Interactive at: https://gis.cdc.gov/GRASP/Fluview/PedFluDeath.html.

Laboratory Data:
Nationally, the percentage of respiratory specimens testing positive for influenza viruses in clinical laboratories during the week ending October 13 was 0.8%. Regionally, the three week average percent of specimens testing positive for influenza in clinical laboratories ranged from 0.2% to 4.0%. During the week ending October 13, of the 92 (0.8%) influenza-positive tests reported to CDC by clinical laboratories, 63 (68.5%) were influenza A viruses and 29 (31.5%) were influenza B viruses. The most frequently identified influenza virus type reported by public health laboratories was influenza A virus. During the week ending October 13, 19 (86.4%) of the 22 influenza-positive tests reported to CDC by public health laboratories were influenza A viruses and 3 (13.6%) were influenza B viruses. Of the 18 influenza A viruses that were subtyped, 4 (22.2%) were H3N2 viruses and 9 (75.0%) were a (H1N1)pdm09 viruses. The majority of the influenza viruses collected from the United States during May 20 through October 13, 2018 were characterized antigenically and genetically as being similar to the cell-grown reference viruses representing the 2018–2019 Northern Hemisphere influenza vaccine viruses. None of the viruses tested from May 20-October 13, 2018 at were found to be resistant to oseltamivir, zanamivir, or peramivir. Antiviral resistance data will be updated weekly starting later in the season.

Source: CDC