In late 2017, the US Centers for Disease Control and Prevention (CDC) released a health advisory related to increased activity of influenza A (H3N2) viruses. In previous years, the H3N2 strain has been associated with decreased vaccine effectiveness and increased rates of hospitalization and deaths among pediatric patients.1 It is important for the pediatrician to understand the strengths, weaknesses, and limitations of current testing for influenza as well as identify testing modalities that might be more appropriate for their clinics in the future.
Recommendations for treatment of influenza
Given current recommendations for treatment of influenza in children,2 the pediatrician needs to consider the operating characteristics and limitations of influenza testing in making clinical decisions to test and treat. Because treatment should be offered or considered for any of the groups in Table 1, testing also needs to be considered for these groups.
Underidentification and overtreatment
Although influenza testing and treatment is recommended for a number of different groups, clinical practice appears to be suboptimal.3,4 Among children evaluated at 7 hospitals of the New Vaccine Surveillance Network during the 2015-2016 flu season, 52% of children (range 25%-84%) admitted for influenza were treated with antivirals.5
Placing an increased emphasis on testing can result in:6
· Rapid diagnosis and treatment with antiviral medication.
· Fewer additional diagnostic tests.
· Fewer hospitalizations.
· More appropriate infection control for hospitalized patients.
· More appropriate antibiotic use.
Recommendations for influenza testing
Laboratory testing for influenza virus should be undertaken when a child has flu symptoms and the results will impact management of the patient, including those at high risk.2,7 See Table 2 for children to consider for testing. The CDC recommendations for testing are depicted in the Figure.8
Some key points to remember include:2,7,9
· Laboratory confirmation of influenza is not needed to initiate treatment.
· Antiviral prescriptions do not need to be delayed until confirmation of influenza by diagnostic testing, especially if flu is in the community and the patient has signs and symptoms compatible with the flu.
· Patients at high risk of significant morbidity or complications should be treated based on clinical suspicion and influenza activity in the community.
· Vaccination does not exclude a diagnosis of influenza.