Monday, November 15, 2021

University of Michigan: CDC & County Health Department Investigating Flu Outbreak

Credit CDC FluView Epi Week 44


Although it is still early in the fall/winter respiratory season - and you wouldn't guess it by looking at the most recent FluView ILI map (above) - over the past ten days we've seen several large outbreaks of seasonal influenza reported from Universities in two states (Rhode Island & Florida). 

More Early Reports Of Seasonal Flu Activity (Florida)

Rhode Island: Early Reports Of Seasonal Influenza

While influenza was a no-show last year - effectively blocked by social distancing, the near-universal wearing of face masks, and a dearth of national or international travel - conditions this fall are radically different, and there are concerns over the lack of community immunity to influenza after nearly two years with little or no exposure. 

There are also a few studies (see PHE Study: Co-Infection With COVID-19 & Seasonal Influenza), suggesting that coinfection with COVID and influenza could result in more severe illness and increased mortality rates. We've seen recent laboratory animal studies that seem to back up that concern (see Nature: Co-infection of SARS-CoV-2 & Influenza Causes More Severe and Prolonged Pneumonia in Hamsters).

This `double whammy' of flu and COVID - assuming it materializes - could make a bad COVID winter worse, particularly for healthcare delivery systems, which are already under pressure. A few recent blogs on those concerns:

UK: Preparing For A "Reasonable Worst-Case" Winter Scenario

ECDC Warns Of Potentially Severe Flu Season Ahead

CDC Concerned Over Low Estimate Of Flu Vaccine Uptake this Fall

Which brings us to today's report, from the University Record of the University of Michigan, detailing an unusually large, and early, spike in influenza on their Ann Arbor Campus, and announcing a joint investigation by the Washtenaw County Health Department, the Michigan Department of Health and Human Services, the University, and a special Epi-Aid team on loan from the CDC.

An excerpt from today's report, after which I'll return with a bit more. 
CDC in Ann Arbor to research flu cases on campus

Byline: By Dana Elger
A large and sudden increase in cases of influenza among students on the University of Michigan’s Ann Arbor campus will be the focus of federal health experts seeking to learn more about how the flu is spreading and vaccine effectiveness as the nation heads into the flu season.

The work — which begins this week — is being led by Washtenaw County Health Department, Michigan Department of Health and Human Services and the university with a team from the Centers for Disease Control and Prevention.

Since the first positive case on Oct. 6, there have been 528 cases of influenza diagnosed at the University Health Service, with 77.1 percent of cases in unvaccinated individuals. UHS officials saw increases in cases of influenza the past two weeks, with 313 cases (37 percent test positivity) the week of Nov. 8 and 198 cases (27.2 percent test positivity) the previous week.

“Through prompt detection and collaboration with county and state health officials, as well as School of Public Health and Michigan Medicine researchers, we quickly identified these cases as influenza A(H3N2) virus infections,” said Lindsey Mortenson, UHS medical director and acting executive director.

“Partnering with the CDC will accelerate our understanding of how this flu season may unfold regionally and nationally in the setting of the COVID-19 pandemic.”

The timing of the increase in cases comes as many U-M students prepare to depart campus for destinations across the country and globe as individuals return to their permanent residences for the Thanksgiving break.

Officials are calling on the entire community to get vaccinated against influenza as soon as possible.

Last week the Washtenaw County Health Department reported (see below) increasing flu activity in the community, although the state of Michigan's weekly flu surveillance report (week ending Oct 30th), showed only low activity. 

Flu Activity
Nov 10, 2021:
  • Flu diagnoses are increasing in Washtenaw County, especially in the University of Michigan community.
  • Influenza A is the predominant strain that is circulating in Washtenaw County, with A/H3 being the dominant subtype.
  • The influenza vaccine is available. It is critical for everyone 6 months and older to be vaccinated against flu in order to prevent severe disease and hospitalizations.
  • Data will be updated weekly, on Wednesday. **Due to ongoing COVID-19 work in Washtenaw County, updates to the weekly flu curve may be delayed.

To better understand the scope of this outbreak, local officials have requested an Epi-Aid Team from the CDC (see website excerpt below). 

Epidemiologic Assistance (Epi-Aids)

What is an Epi-Aid?

An Epi-Aid is an investigation of an urgent public health problem, such as infectious or non-communicable disease outbreaks, unexplained illnesses, or natural or manmade disasters. When a public health authority requests assistance from the U.S. Centers for Disease Control and Prevention, an Epi-Aid allows rapid, short-term (1–3 weeks), generally onsite, technical assistance by Epidemic Intelligence Service (EIS) officers and other CDC subject matter experts. The focus of an Epi-Aid investigation is to assist partners in making rapid, practical decisions for actions to prevent and control the public health problem.

Who participates?

An Epi-Aid team includes at least one EIS officer and other CDC subject matter experts. This team joins local staff in the community where assistance is requested. The requesting public health authority provides overall leadership for the investigation, while the Epi-Aid team provides technical assistance.

Who can request an Epi-Aid?

Various officials with authority for public health can request an Epi-Aid.

State and territorial public health authorities
Local public health authorities, in coordination with the state authorities
Elected tribal leaders of federally recognized tribes
Foreign countries’ ministry of health authorities
Federal agency officials
American military base commanding generals
CDC’s Vessel Sanitation Program officials

Can a local jurisdiction request an Epi-Aid?

Yes. CDC responds to direct requests from local jurisdictions. When a local jurisdiction requests an Epi-Aid, CDC is committed to ensuring the state is aware of the request and is appropriately engaged in the Epi-Aid. The EIS program frequently helps with coordination among the state and local jurisdictions and CDC programs.

Printable PDF fact sheet pdf icon[230 KB, 2 pages, 508] 

          (Continue . . . )

While it is impossible to know exactly what kind of flu season we have ahead, these early outbreaks of influenza - combined with the upcoming Thanksgiving Travel holiday - should provide additional incentive to get the seasonal flu vaccine, and continue to practice good `respiratory hygiene' this fall and winter. 

While another challenging winter may lay ahead of us, there are still things we can to to lessen its impact.  Assuming we have the will to do so.