The Centers for Disease Control and Prevention has issued the following Health Alert regarding elevated influenza activity across the United States.
HEALTH ALERT
Summary
This health advisory notifies clinicians that influenza activity remains high in the United States. Ongoing elevated activity is due to influenza B/Victoria viruses, increasing circulation of influenza A(H1N1)pdm09 viruses, and low levels of influenza B/Yamagata and influenza A(H3N2) viruses.
The CDC’s influenza forecasts suggest that national influenza activity will remain elevated for several more weeks.
Because influenza activity is elevated and both influenza A and B virus infections can cause severe disease and death, this health advisory also serves as a reminder that early treatment with antiviral medications improves outcomes in patients with influenza.
Early treatment with antiviral medications is recommended for hospitalized patients and high-risk outpatients, including children younger than two years. Clinicians should continue efforts to vaccinate patients for as long as influenza viruses are circulating, and promptly start antiviral treatment of severely ill and high-risk patients with suspected influenza without waiting for laboratory confirmation.
Background
In the United States, influenza activity remains elevated and widespread, and the season is likely to last several more weeks (see CDC FluView report for details: https://www.cdc.gov/flu/weekly/index.htm).
Since early this season, influenza B viruses, specifically B/Victoria viruses, have been reported more frequently than other influenza viruses, followed by A(H1N1)pdm09. Different viruses have predominated in different parts of the country and among different age groups.
Influenza B viruses can cause severe illness in people of all ages, including children.
In past seasons, the percentage of influenza B viruses detected in children who died with influenza has generally been higher than the percentage of B viruses detected in the general pediatric population, and pediatric mortality from influenza B–associated hospitalizations have been reported to be higher than with influenza A–associated hospitalizations.
So far this season, influenza B virus infections account for about half of hospitalizations reported through CDC’s laboratory-confirmed influenza hospitalization surveillance network and the majority of reported influenza-associated pediatric deaths (https://www.cdc.gov/flu/weekly/index.htm).
Influenza A(H1N1)pdm09 viruses are increasing and becoming predominant in some regions. These viruses can also cause severe illness, particularly in adults not originally exposed to currently circulating A(H1N1)pdm09 viruses.
Influenza A(H1N1)pdm09 viruses currently comprise the majority of the other half of hospitalizations reported through CDC’s laboratory-confirmed influenza hospitalization surveillance network.
CDC continues to recommend everyone six months of age and older get vaccinated for influenza. CDC also recommends antiviral medications for the treatment of influenza, because antiviral treatment has shown clinical and public health benefit in reducing illness and lessening severe outcomes of influenza based on evidence from randomized controlled trials, meta-analyses of randomized controlled trials, and observational studies during past influenza seasons and during the 2009 H1N1 pandemic.
For Nebraska Influenza Data please see the Nebraska Influenza Surveillance report at http://dhhs.ne.gov/Flu%20Documents/Report.pdf
Influenza antiviral medications are most effective in treating influenza and reducing complications when treatment is started early (within 48 hours of illness onset). Some studies suggest clinical benefit among hospitalized patients and young children with febrile illness even when treatment was started three to five days after illness onset.