January 11, 2018

Influenza Surveillance Update – Alicia Budd (CDC)

Alicia provided highlights of the influenza surveillance report from week 52, ending on December 30, 2017. Since our last Summit call, there has been a sizeable increase in influenza activity throughout the country.

The percentage of respiratory specimens testing positive for influenza in clinical laboratories was 25.5%, up from 21.7% the previous week. The majority of specimens (84.9%) tested at public health laboratories were influenza A, and 15.1% were influenza B. Influenza A H3 continues to be the dominant strain reported, though smaller numbers of influenza A (H1) and influenza B also have been reported. Specimens characterized since May have been antigenically and genetically similar to the reference virus for this season’s vaccine. There has been no antiviral resistance detected to date.

Nationwide, influenza-like illness (ILI) activity was at 5.8%, up from 4.9% the prior week. All 10 of the HHS regions are above their region-specific baselines. ILI information also is available on a state level, with activity summarized as high, moderate, low, or minimal. Last week, 26 states reported high ILI activity, 9 states and Puerto Rico reported moderate ILI activity, 6 states and the District of Columbia reported low ILI activity, and 9 states reported minimal ILI activity.

Based on reports from the National Center for Health Statistics (NCHS) surveillance system available for the week ending December 17, 6.7% deaths were due to pneumonia and influenza (P&I). This percentage is below the epidemic threshold of 6.9% for the week.

Information from the Influenza Hospitalization Surveillance Network (FluSurv-NET) indicates an overall hospitalization rate of 13.7 per 100,000 population. The highest rate (56.6 per 100,000) was among adults aged >65 years, followed by adults aged 50–64 (15.4 per 100,000 population) and children aged 0–4 years (9.9 per 100,000 population).

Six (6) influenza-associated pediatric deaths have been reported since our last Summit call. For the 2017–2018 season, the total number of reported pediatric deaths is 13. Of these, 3 were typed as H3N2, 3 were H1N1, 4 were influenza A that was not subtyped, and 3 were influenza B.

In terms of geographic spread of influenza within a state (characterized as regional, local, sporadic, or no activity) as reported by state and territorial epidemiologists, 46 states reported widespread activity, 4 states reported regional activity, the District of Columbia reported local activity, and 0 states reported sporadic activity. No reports were received from Guam, Puerto Rico, and the US Virgin Islands.

In summary, there has been a significant increase in influenza activity in the US during recent weeks. However, it is too early in the season to determine anything about the intensity of this year’s virus and whether or not we have reached a seasonal peak in the number of reported cases.

Alicia also reminded callers about the Health Alert Network (HAN) report issued on December 27, 2017. The point of the HAN was to alert clinicians about the jump in influenza activity and its clinical implications, as well as to provide a summary of antiviral recommendations, which remain unchanged from previous years. She also noted that spot shortages of antivirals have been reported due to high demand in a particular community, but there is not a shortage for the nation as a whole.

Announcements – Amy Parker Fiebelkorn

2018 Summit In-Person Meeting

Amy reminded callers that the 2018 Summit in-person meeting will be held in conjunction with the National Immunization Conference (NIC) in Atlanta, Georgia. The NIC will be May 15–17, and the Summit will be May 17–18. Attendees are encouraged to participate in both events.

Information on registration and submission of poster abstracts for NIC is now available online. (Persons needing to receive the password to access the site may contact L.J Tan.) The poster/networking session will be held on Thursday evening, May 17.

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