January 10, 2019

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January 10, 2019

Amy Parker Fiebelkorn facilitated today’s call.

Influenza Surveillance Update – Alicia Budd (CDC)

Alicia provided an update on influenza activity reported for week 52, ending December 29, 2018. Influenza activity is continuing to increase across the country.

For the week, almost 14% of specimens sent to clinical laboratories tested positive for influenza. To put this into context, the percent positives for the last three seasons has peaked from 24 – 27%. H1 is the predominant virus to date. At public health labs, 95% of the viruses tested have been influenza A, and 81% of these were H1 viruses. Nine of the 10 surveillance regions are H1 predominant. However, Region 4 (southeastern states) has been unusual in reporting H3 as the predominant strain. Only 5% of specimens tested at public health labs have been influenza B. Of these, 63% are of the Yamagata lineage. Most of the small numbers of B Victoria cases seen to date have been clustered in smaller areas, primarily in Maryland and Montana.

During this season, almost 400 viruses have received antigenic and genetic characterization. This data indicates the majority of viruses are similar to this season’s vaccine components. In addition, none of the almost 400 viruses tested for resistance to oseltamivir, peramivir, and zanamivir has been found to be resistant.

During the week, outpatient visits for influenza-like illness (ILI) increased to just over 4%, compared to 3.3% during the previous week. We have been above the national baseline for 6 consecutive weeks. All 10 surveillance regions were above their region-specific baseline. On a state level, 19 states experienced high ILI levels, 9 reported moderate activity, and the remaining 22 states were at low or minimal activity levels.

Cumulative reports to FluSurv-NET this season indicate a rate of 5.4/100,000 lab-confirmed influenza hospitalizations. Highest hospitalization rates were in the 0–4 age group at 14.5/100,000, followed by persons >65 years at 11.9/100,000.

The percent of deaths reported due to pneumonia and influenza (P&I) remained below the epidemic threshold, with 6.1% of deaths due to P&I.

A total of 13 pediatric deaths have been reported to CDC this season. The majority (12) were associated with influenza A, and most of these were H1. One influenza B was reported among these pediatric deaths. Information on the vaccination status of these cases will be reported after the total numbers are higher. However, Amy noted that typically about 20% of reported pediatric deaths have a history of influenza vaccination.

For the geographic spread of influenza during the week, 24 states reported widespread activity, 18 states reported regional activity, and 8 states reporting local or sporadic activity.

Effectiveness of Cell-culture and Egg-based Influenza Vaccines – Brendan Flannery (CDC)

Brendan provided a presentation on influenza vaccine effectiveness (VE). The main information he discussed came from a recent publication in The Journal of Infectious Diseases, Relative effectiveness of cell-cultured and egg-based influenza vaccines among the U.S. elderly 2017–18. Brendan and Alicia Fry with CDC wrote an accompanying editorial commentary (Comparing influenza vaccine types: the path towards improved influenza vaccine strategies) to this article.

By way of background, Brendan referred Summit partners to a New England Journal of Medicine study published in 2014, Efficacy of High-dose versus Standard-Dose Influenza Vaccine in Older Adults. In this large randomized trial, high-dose vaccine was found to be 24% more efficacious against laboratory-confirmed influenza during 2 influenza seasons (2011–12 and 2012–13). Background for the current study came from a Lancet article published in 2015, Comparative effectiveness of high-dose versus standard-dose influenza vaccine in US residents aged 65 years and older from 2012 to 2013 using Medicare data: a retrospective cohort analysis. This observational study examined Medicare claims data and found that 19% received high-dose vaccine and 81% received standard-dose vaccine. The results indicated the high-dose vaccine was 22% more effective than standard-dose vaccine against influenza-associated office visits and hospitalizations.

The 2017–2018 season was severe and predominantly A(H3N2). A large burden of disease occurred among older adults age >65 years. CDC estimated VE at 40% against any influenza illness, but only 24% effective against A(H3N2)-related illness. Multiple types of influenza vaccines (including standard-dose, high-dose, adjuvanted, recombinant, and cell-culture) were licensed and recommended for persons in this age group. Brendon noted that the recombinant and cell-culture vaccines avoid the antigenic changes in the vaccine virus resulting from growing the viruses in eggs.

An observational FDA study of Medicare beneficiaries during the 2017–18 season found that the majority (63%) received the high-dose vaccine. Although only 5% of beneficiaries received cell-culture vaccine, the large numbers of persons included allowed comparisons between the two products. Influenza-diagnosed hospitalizations were 10% lower among beneficiaries who received cell-culture vaccine compared to egg-based vaccine. Influenza office visits were 6% lower in the cell-culture group. Comparisons were more difficult for standard-dose trivalent vaccine recipients, as this group had low rates of office visits.

The data appears to indicate that cell-culture vaccines have improve effectiveness over egg-based vaccines. The cell-culture vaccine had a similar VE to that found with high-dose vaccine containing 4 times the antigen content. Egg-adapted changes are only one factor affecting VE. Brendon briefly discussed the importance of observational data in comparing different types of vaccines. He noted that incremental improvements in VE put us on the path to better vaccines.

One caller asked about a similar study conducted in a younger age group by Kaiser Permanente in California. The overall VE in this study showed approximately 7% difference. This study has not yet been published, however.

Brendan noted the importance of options for seniors, as we do not have evidence of superiority of cell-based vs high-dose vaccines. He stated this may be a cautionary tale about jumping too quickly on preferential recommendations when we still have promising vaccines for all age groups. He hopes this will provide incentives for the development of new vaccines. In response to a question, he noted that we do not have laboratory-confirmed information on influenza H3N2 for last season.

One caller noted the difficulty of vaccine messaging without recommending one vaccine over another. The adjuvanted vaccine appeared to have some improvement, but less than the cell-culture or high-dose. Brendan acknowledged the difficulty providers face in vaccine communications. He felt the best message for the public might be to emphasize the ACIP-recommended vaccines and to talk with a provider about the options that might be best for each individual.

PneumoRecs VaxAdvisor App – Alison Albert (CDC)

Alison’s presentation offered an overview of CDC’s new PneumoRecs VaxAdvisor app to assist providers in navigating complex pneumococcal vaccine recommendations. The current recommendations for use of PCV13 and PPSV23 vaccines are summarized in 6 different publications. Initially CDC had created a job aid to assist providers making pneumococcal vaccine recommendations for adults. However, this was still extremely complex and difficult for providers to understand. The new mobile app allows providers to enter a patient’s DOB and answer questions about possible underlying health conditions, along with a patient’s prior pneumococcal vaccine history. The result provides customized recommendations for individual patients on which vaccines should be given both now and in the future. Small bugs are still being corrected in the system, and a new section will provide links to additional resources. CDC will begin a large publication effort about the app in the near future.

Other Items – L.J Tan (IAC)
  • In-Person Summit Meeting – This annual meeting will be held in Atlanta on May 14 – 16, 2019. A registration page, including a link to the draft agenda, will be available online in the near future.
  • New Immunization Tip Sheet from ACOG – The American College of Obstetricians and Gynecologists (ACOG) has just released a new resource, Strategies for Integrating Immunizations into Routine Obstetric-Gynecologic Care, Although this was developed for Ob-Gyns, it provides information helpful to any adult vaccine provider. The strategies highlighted on the tip sheet are based on findings from a CDC-funded ACOG adult immunization project. Additional details about the project and the strategies detailed in the tip sheet can be found in the final report on the project’s demonstration phase. Other helpful immunization resources are available on ACOG’s Immunization for Women website.
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