H1N1 COUNTERMEASURES STRATEGY AND ... - PHE Home

NBSB Pandemic Influenza Working Group
Detailed Report
for influenza-like illness (ILI), hospitalized, or died. CDC is working on methods to
improve the accuracy of surveillance for these cases and for those who do not seek
treatment. Determining the denominator—that is, all the people infected—is much more
difficult. We want diagnostics that can turn ILI surveillance into combined ILI and
biologic surveillance, said Dr. Pavia.
Data on the incidence of hospitalization by age and by State show that hospitalization is
highest in the very young and declines by age. It’s not clear why cumulative incidence
varies by State. Dr. Pavia wondered if there is bias in the diagnoses. Expanding clinical
diagnostic testing at sentinel sites can provide more complete and accurate data, but it’s
expensive and may not be rapid enough to affect management. Dr. Pavia said his
hospital provides daily counts to unit managers and clinicians, which is informative but
may not offer much value in making treatment decisions. Dr. Pavia pointed out that in
his hospital system, the number of diagnostic tests performed peaked before the virus
arrived and early in the outbreak the system had no antivirals to treat H1N1.
Point-of-care (POC) testing generally has good positive predictive value (PPV) and poor
negative predictive value (NPV). Dr. Pavia asked whether it’s more important to have a
high PPV so you can isolate patients or a high NPV to spare the use of drugs. In most
cases, a POC test must be CLIA-waived. Questions remain about whether the turnaround
time of a POC test justifies the expense and affects patient management. In the long
term, does POC testing affect the use of antivirals (for better or worse) or does it lead to
overuse of antibiotics? Dr. Pavia described the case of a Salt Lake City woman who died
of hemorrhagic pneumonia after contracting H1N1; she tested negative for H1N1 despite
exposure.
Dr. Pavia challenged the participants to consider the ideal strategic goals for public health
diagnostic testing, and to consider the goals for secondary and tertiary care centers. If
diagnostics are important, should strategies encourage development and deployment, e.g.,
by this fall? How do we ensure diagnostic tests are accessible and affordable - and that
they meet quality expectations?
Influenza Diagnostic Preparedness and Response—Dan Jernigan, M.D., M.P.H.,
National Center for Immunization and Respiratory Diseases, CDC
Dr. Jernigan described some lessons learned, noting that some of the pandemic influenza
planning was right on, while some was far off the mark. Public health authorities
expected that the virus would be H5N1 and that it would be severe, virulent, and easily
transmitted. They anticipated high fatalities and believed the pandemic would originate
in Southeast Asia and hit other countries first. Dr. Jernigan said the flexibility put in
place for surveillance efforts and the broad views provided us with early information.
In 2007, CDC determined an internal strategy for diagnostic preparedness that included
developing new diagnostic tests and improving diagnostic capacity. It awarded a 10-year
contract to develop the Influenza Reagent Resource (IRR), which would facilitate
distribution of reagent for manufacturers and others. The IRR is now fully functional and
55