January 18, 2018

Influenza Surveillance Update – Alicia Budd (CDC)

Alicia provided highlights of the influenza surveillance report from week 1, ending January 6, 2018. Influenza activity has continued to increase, though not at such a sharp level as has been observed in recent weeks.

The percentage of respiratory specimens testing positive for influenza in clinical laboratories was 24.7%, down slightly from the 25.1% positive reported in the previous week. However, Alicia cautioned that this slight decrease does not necessarily mean we have reached the seasonal peak. Week 1 included a holiday, which could have negatively impacted the level of testing and specimen submission. The majority of specimens (~87%) tested at public health laboratories were influenza A, and ~13% were influenza B. At 91%, influenza A H3 continues to be the dominant strain reported, though smaller numbers of influenza A (H1) and influenza B also have been reported. Of the influenza B specimens on which lineage testing was performed, slightly more than 90% were B Yamagata. Specimens characterized since May continue to be antigenically and genetically similar to the reference virus for this season’s vaccine. Of the several hundred viruses that have been tested, only 2 have shown any antiviral resistance. Both of these virus samples were H1N1, which is not the predominant strain this season.

A Summit member asked whether the amount of influenza B activity we are seeing is atypically high for this time of year. Alicia agreed that the amount is higher than we have seen for several years. She noted that in other parts of the world, influenza B actually has been the predominant strain. The U.S. has not seen an influenza B predominant season in many years. It could be that we’re seeing a higher background level of influenza B and the more typical late season “wave” is still to come.

Nationwide, influenza-like illness (ILI) activity was at 5.8%, up slightly from the 5.7% reported in the prior week. This is the 7th consecutive week that we have been at or above baseline ILI levels. All 10 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 and New York City reported high ILI activity, 10 states and Puerto Rico reported moderate ILI activity, 6 states and the District of Columbia reported low ILI activity, and 8 states reported minimal ILI activity.

Based on reports from the National Center for Health Statistics (NCHS) surveillance system available for the week ending December 22, 7.0% of deaths were due to pneumonia and influenza (P&I). This is the first time this season that we have reached the epidemic threshold.

Information from the Influenza Hospitalization Surveillance Network (FluSurv-NET) indicates an overall hospitalization rate of 22.7 per 100,000 population. The highest rate (98.0 per 100,000) was among adults aged >65 years, followed by adults aged 50–64 (24.0 per 100,000 population) and children aged 0–4 years (16.0 per 100,000 population).

Seven (7) influenza-associated pediatric deaths were reported during week 1. For the 2017–2018 season, the total number of reported pediatric deaths is 20. Of these, 4 were typed as H3N2, 4 were H1N1, 6 were influenza A that was not subtyped, and 6 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, 49 states reported widespread activity, 1 state (Hawaii) and Guam reported regional activity, the District of Columbia reported local activity, and 0 states and the U.S. Virgin Islands reported sporadic activity. No report was received from Puerto Rico. Alicia noted that this is the first time since the definitions for geographic spread were changed 13 years ago that all states in the continental U.S. have reported widespread activity at the same time.

Announcements – LaDora Woods (CDC)

2018 Summit In-Person Meeting

LaDora 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 the Summit 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.

Immunization Excellence Awards

Summit members are encouraged to submit nominations for the 2018 Immunization Excellence Awards, which will be presented at the annual Summit meeting. Awards will be presented in the following categories:

  • Non-Healthcare Employer Campaign
  • Laura Scott NAIIS Immunization Excellence Award for Oustanding Influenza Season Activities Campaign
  • “immunization Neighborhood” Adult Immunization Champion
  • Corporate Campaign
  • Adult Immunization Publication Award

The deadline for submission of nominations is February 1, 2018.

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