Novel influenza A(H1N1) in a pediatric health care facility in New York City during the first wave of the 2009 pandemic

Preventing and treating secondary bacterial infections with antiviral agents

Bacterial super-infections contribute to the significant morbidity and mortality associated with influenza and other respiratory virus infections. There are robust animal model data, but only limited clinical information on the effectiveness of licensed antiviral agents for the treatment of bacterial complications of influenza. The association of secondary bacterial pathogens with fatal pneumonia during the recent H1N1 influenza pandemic highlights the need for new development in this area. Basic and clinical research into viral-bacterial interactions over the past decade has revealed several mechanisms that underlie this synergism. By applying these insights to antiviral drug development, the potential exists to improve outcomes by means other than direct inhibition of the virus.

Natural history of pandemic H1N1 2009 influenza infection in healthy pediatric outpatients

OBJECTIVE

The pandemic influenza H1N1 2009 (pH1N1) virus is expected to remain a prominent circulating strain in the current and subsequent influenza seasons. The objective of this study was to compare the clinical course of infection with laboratory-confirmed pH1N1 and seasonal influenza A and B in a cohort of previously healthy children managed in the outpatient setting without antiviral therapy.

METHODS

Previously healthy children 17 years of age or younger were prospectively enrolled during the first wave of the 2009 pandemic (May-July 2009) and the 2 preceding influenza seasons from a single primary care physician office and a tertiary children's hospital emergency department. Inclusion criteria were: age ≤17 years; laboratory-confirmed influenza; and not receiving antiviral agents. Follow-up telephone interviews were conducted approximately 2 days and 14 days after presentation to assess symptom duration.

RESULTS

A total of 251 patients (101 with pH1N1, 90 with seasonal influenza A, 60 with seasonal influenza B) were included. Presenting symptoms and duration of symptoms associated with pH1N1 were similar to those with seasonal influenza. Median fever duration in pH1N1 was 3 days and had resolved within 8 days in 95% of patients. Among patients with pH1N1, abnormalities on chest auscultation (10 of 101), the hospitalization rate (2 of 101), the proportion of children receiving intravenous fluid therapy (1 of 101) or supplemental oxygen (1 of 101) were not significantly different from patients with seasonal influenza.

CONCLUSIONS

In most children without underlying risk factors for severe influenza, pH1N1 virus causes an uncomplicated respiratory tract illness, no more severe than seasonal influenza.

Signs of the 2009 influenza pandemic in the New York-Presbyterian Hospital electronic health records

Background

In June of 2009, the World Health Organization declared the first influenza pandemic of the 21^st century, and by July, New York City's New York-Presbyterian Hospital (NYPH) experienced a heavy burden of cases, attributable to a novel strain of the virus (H1N1pdm).

Methods and Results

We present the signs in the NYPH electronic health records (EHR) that distinguished the 2009 pandemic from previous seasonal influenza outbreaks via various statistical analyses. These signs include (1) an increase in the number of patients diagnosed with influenza, (2) a preponderance of influenza diagnoses outside of the normal flu season, and (3) marked vaccine failure. The NYPH EHR also reveals distinct age distributions of patients affected by seasonal influenza and the pandemic strain, and via available longitudinal data, suggests that the two may be associated with distinct sets of comorbid conditions as well. In particular, we find significantly more pandemic flu patients with diagnoses associated with asthma and underlying lung disease. We further observe that the NYPH EHR is capable of tracking diseases at a resolution as high as particular zip codes in New York City.

Conclusion

The NYPH EHR permits early detection of pandemic influenza and hypothesis generation via identification of those significantly associated illnesses. As data standards develop and databases expand, EHRs will contribute more and more to disease detection and the discovery of novel disease associations.