Influenza Surveillance Update – Alicia Budd (CDC)
Alicia provided an update on influenza activity for Week 49, through the week ending December 7, 2019. Flu activity is continuing to increase across the country. Elevated activity has occurred for the last 5 weeks.
Clinical labs reported 11% of submitted specimens were positive for influenza, compared with 10% the previous week. Public health labs reported widespread influenza with a mixture of strains among B Victoria (the most commonly reported), H1, and H3. This mixture varies by region of the country, with 7 of 10 regions reporting B Victoria most frequently, while other regions reported predominantly H1 (2 regions) and H3 (1 region). Strain differences also were reported among different age groups. Overall, for persons 0–24 years of age, B Victoria is predominant, while H3 is reported more frequently in persons >65. Reports from middle age adults were almost equally split between H1 and B Victoria.
Genetic characterization of influenza viruses continues to increase. All H1 strains tested were from clade 6B.1A and were similar to the cell-grown reference virus. Characterized H3 viruses belonged to the 3C.2a1 clade/subclade, which varies from the 3B.3a clade used in the vaccine. In spite of this antigenic difference, 71% of viruses characterized were similar. For B Victoria, there was a split in the triple and double deletion viruses. Sixty-three percent (63%) B viruses were similar to the cell-grown reference virus. Of the small number of B Yamagata viruses tested, all were similar to the vaccine virus. Ninety-nine percent (99%) of viruses tested were susceptible to the antiviral medications oseltamivir, zanamivir, peramivir, and baloxavir.
Outpatient influenza-like illness (ILI) activity was at 3.2%, slightly down from the previous (Thanksgiving) week. Past years have indicated changes to health-seeking behavior during the holidays, so it is anticipated this level will rise during the next week of reporting. Despite this small decline, all 10 regions are now reporting levels at or above baseline rates. State ILI activity also slightly decreased, with 12 state reporting high levels of influenza activity, compared with 13 the previous week.
Cumulative hospitalization rates for the season are at 3.9 per 100,000 for the overall population. Highest rates are seen in age 65 and above, followed by the 0–4 year age group. Rates of reported pneumonia and influenza (P&I) are still below threshold levels for the season.
Four (4) new influenza-related pediatric deaths were reported during the week, bringing the 2019–2020 total for pediatric deaths to 10.
The majority (38) of states are reporting regional or widespread influenza activity. Estimated in-season burden of influenza estimates are 2.6 million persons infected, 23,000 hospitalizations, and 1,300 deaths.
Other Items – L.J Tan
- 2020 Summit Meeting – This year’s meeting will be held on May 18, the day prior to the opening of the National Immunization Conference. Information on registration and other pertinent details is available on the Summit website. Nominations are being accepted for the 2020 Immunization Excellence Awards through February 1, and J especially thanked Mitch Rothholz for his many faithful years of coordinating these awards. The deadline for a poster submission is March 15.
- 2030 Healthy People Objectives – L.J announced that the Secretary of Health and Human Services has signed off on the 2030 objectives. There are 509 objectives covering 43 topic areas. Of particular interest, the adult immunization objective championed by the Summit, NVPO, and CDC has been added as a developmental objective. In addition, an objective has been included on the importance of incorporating information across the lifespan into IIS. The 2030 Objectives are scheduled for release at the end of March.
- Summit Call Schedule – L.J reminded partners that the next regularly scheduled Summit calls will not be held due to the Christmas and New Year holidays. The next call will occur on January 9.