Influenza Surveillance Update – Alicia Budd (CDC)
Alicia provided a brief update on influenza activity in the United States. Data for influenza activity through Week 13, ending on March 28, 2020, indicates a dramatic drop in laboratory-confirmed influenza activity.
The percent of specimens testing positive for flu dropped from 7.3% during Week 12 to 2.1% in Week 13. It is anticipated this decline will continue into Week 14. A decline also has been seen for reported influenza-like illness (ILI), though this drop has not been as sharp as that seen in the clinical laboratory data. The percent ILI declined from 6.3% in Week 12 to 5.4% in Week 13.
Alicia noted that these data are challenging to interpret right now. By definition, ILI is a broad syndrome. However, CDC does think it is appropriate for this to be used for tracking COVID illness as well; they are keeping a close eye on ILI reporting to correlate it with flu lab positivity and COVID testing positivity. Keeping this in mind, we are seeing dramatic changes in healthcare seeking behavior due to COVID. In particular, there is a big push to use telemedicine, as well as general recommendations that suggest limiting emergency department visits to only the most severe illnesses. We’re seeing vast increases in social distancing, which affects both the numbers of people seeking care and their reasons for visits. However, the decline in ILI is not nearly as sharp as that for percent influenza positivity, lending it to a means to look at COVID-19 activity.
Cumulative influenza hospitalization rates continue to increase, but at a much slower pace than seen earlier in the season. For all ages combined, the cumulative rate is nearly 68/100,000. At nearly 179/100,000, the highest rates continue to be in the 65 and older age group. For the week ending March 21, there was a substantial jump (from 7.8% to 8.2%) in the percentage of deaths due to pneumonia and influenza (P&I). When CDC examined the relative contribution of pneumonia vs influenza in these deaths, they learned that the percentage of deaths due to influenza had declined, while those due to pneumonia had increased. It is probably safe to assume that at least some of this increase in pneumococcal deaths was due to pneumonia resulting from COVID-19.
Seven (7) influenza-related pediatric deaths were reported during the week, bringing the 2019–2020 total for pediatric deaths to 162. The vast majority (102, or 63%) of these deaths were associated with influenza B virus infection. Of these viruses with lineage testing, all were B Victoria. For influenza A viruses, 35/60 were subtyped. Of these, 34 were H1 and one was H3.
Preliminary in-season influenza burden estimates have not changed to a great extent. For the season as a whole, there have been at least 39 million flu-related illnesses, at least 400,000 flu-related hospitalizations, and at least 24,000 deaths.
Alicia noted that the full FluView report for Week 14 will be posted on April 11. After that, as activity is continuing to decrease, a more abbreviated report will be issued that does not contain as many interpretations of the data. This is similar to the reports typically released during the summer. She also mentioned that CDC is now publishing a “sister” publication, COVIDView, which contains similar data elements. This will allow people to become accustomed to using this publication for tracking COVID-19 surveillance information.
One Summit partner noted that influenza testing typically drops later in the season and asked if that might have had an impact on the lower percent positivity. Alicia stated that there actually had been an increase in specimens being tested for influenza. In spite of that, the percent positives showed a pronounced decline. Therefore, we can be relatively comfortable that this is actually due to decreased incidence.
Carolyn Bridges asked if any of the sites in the National Respiratory and Enteric Viruses Surveillance System (NREVSS) are doing routine testing for a wide range of respiratory viruses. Alicia stated that this network consists of several hundred labs across the country that test for a variety of respiratory pathogens. These labs also will be included in the COVID surveillance report as they come into the system.
Announcements – L.J Tan (IAC)
Summit Activities – L.J thanked Summit partners for their continuing work on the COVID-19 pandemic. He also provided updated information on the continuing activities of the Summit.
- Summit Call Schedule – Summit calls are held each Thursday at 3 pm ET unless otherwise cancelled via an email announcement. Please watch for these announcements in your in-box. In addition, please email L.J or LaDora if you have questions or suggestions for Summit calls.
- In-person Summit Meeting Cancelled – There will be no in-person Summit meeting this year. (In addition, the National Immunization Conference has been cancelled.) If there is some dramatic change in the situation, the Summit leadership will consider re-evaluating this decision, though it is recognized that this is unlikely
- Virtual Meetings Being Planned – In lieu of the in-person meeting, several virtual meetings are being developed to help Summit partners remain current and engaged. As plans are finalized, these meetings will be announced via email and on the Summit website.
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- COVID-19 Vaccine Development – In association with BIO, a meeting is being planned which will focus on the development of new COVID-19 vaccines. Phyllis Arthur with BIO will serve as the moderator of this virtual event. Potentially, the meeting would include some of the manufacturers involved in Phase 1 and Phase 2 trials to allow participants to: (1) learn about scheduling and dosing information so that we can begin considerations about implementing an eventual vaccination program and (2) determine policy issues that will need to be considered assuming multiple vaccines are in the mix.
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- 2020–2021 Influenza Season Information – In an effort to provide some of the information traditionally offered during “Flu Day” at the Summit, vaccine manufacturers will be invited to provide status reports on influenza vaccine and production projections for the 2020–2021 season. The Summit leadership group also hopes to invite CDC representatives to provide a communications update, as well as other scientific information traditionally presented at the in-person meeting.
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- Seasonal Influenza Planning – The Summit hopes to create an influenza plan for this summer and fall. Specifically, how can we motivate the public to engage in prevention and adult vaccines before a potential resurgence of COVID-19 in the fall?
