High-Risk Patient With Possible Flu? Start Those Antivirals

Fiona Havers, MD, MHS


April 20, 2015

Editorial Collaboration

Medscape &

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Hello. I am Fiona Havers, a physician in the Influenza Division at the Centers for Disease Control and Prevention (CDC). I am pleased to be speaking with you today as part of the CDC Expert Commentary Series on Medscape.

Today I will be discussing the results of a study in the journal Clinical Infectious Diseases[1]that examined the use of influenza antiviral medications in patients at high risk for flu complications. This study showed that antiviral drugs continue to be underutilized in high-risk patients in outpatient settings, and also that many high-risk patients wait more than 2 days after symptom onset to seek medical care.

High-risk groups include people aged 65 years and older, young children, pregnant women, and people with underlying medical conditions, such as chronic obstructive pulmonary disease, asthma, congestive heart failure, and diabetes. Observational studies have shown that influenza antiviral drugs can reduce serious flu complications, including hospitalization and death.

CDC recommends beginning empiric antiviral treatment as soon as possible in all severely ill patients (including outpatients with severe progressive symptoms and those who develop such complications as pneumonia) and high-risk patients with suspected flu, without waiting for the results of influenza diagnostic tests. Ideally, treatment should begin within 48 hours of symptom onset, although some observational studies have shown benefits to using antiviral drugs beyond the 48-hour treatment window in hospitalized patients and in patients with severe flu illness.[2,3] CDC currently recommends the US Food and Drug Administration (FDA)-approved antiviral medications oseltamivir, zanamivir, and peramivir to treat influenza illness.

The study examined the treatment practices of clinicians when high-risk outpatients sought medical treatment for acute respiratory illness (ARI) during the 2013-2014 influenza season. The study enrolled approximately 6000 outpatients of all ages who had cough illness that started in the previous 7 days at five sites around the United States. Among those enrolled, 2789 were in a high-risk group.

As part of the study, all patients were tested for influenza using polymerase chain reaction (PCR), although most clinicians did not have access to the influenza test results. Key findings showed that providers prescribed antiviral medications to 43% of high-risk patients presenting to care within 48 hours who were later found to have had laboratory-confirmed influenza. However, even in this select group of patients, who are among those most likely to benefit from antiviral treatment, more than half were not prescribed these medications. Overall, only 15% of high-risk patients with ARI who presented to care early were prescribed antiviral medications.

ARI is a broad and nonspecific syndrome with many causes, and we don't have all of the information that influenced the clinicians' decision-making. These data suggested that in many high-risk patients with ARI, clinicians correctly identified influenza, either by clinical presentation or diagnostic tests. Clinicians clearly increased antiviral prescribing as flu activity increased. During the week of peak flu activity in the study, the proportion of high-risk patients seeking early care who received an antiviral prescription increased to 31%, about twice as high as the proportion of prescriptions during all other weeks. However, even at the peak of flu season, our data suggest that antiviral treatment is underused in high-risk patients.

In addition to low rates of antiviral prescribing among clinicians, the study showed that high-risk patients often wait until after 2 days from symptom onset to seek medical care. In this study, 70% of high-risk patients sought medical care 3 or more days after flu-like symptoms began. Adults aged 65 years and older—one of the most susceptible groups for serious flu complications—were the most likely to seek care after the optimal antiviral treatment window. Pregnant women and children younger than 2 years old, on the other hand, were the most likely to seek care within 2 days of flu symptom onset.

It is important for clinicians to look for ways to reduce the amount of time between the onset of flu-like symptoms in high-risk patients and the start of antiviral treatment. Clinicians can educate their patients about the risk for serious flu complications due to age, health status, and the presence of certain chronic medical conditions. Serious flu-related complications can lead to hospitalization and even death.

Healthcare professionals may also consider offering quicker access to antiviral prescriptions by establishing telephone triage lines in their medical offices, through which clinical staff can determine when it might be appropriate to initiate antiviral treatment before an office visit. CDC has prepared a flowchart as a guide to the evaluation of patients with possible influenza over the telephone.

CDC's antiviral recommendations for clinicians are available on the CDC website.

Web Resources

Influenza Antiviral Medications: Summary for Clinicians

CDC Flu Spotlight: Flu Antivirals Drugs Continue to be Under-utilized in High-Risk Patients

CDC Newsroom: Why CDC Recommends Influenza Antiviral Drugs

Medical Office Telephone Evaluation of Patients with Possible Influenza

People at High Risk of Developing Flu-Related Complications

FDA Influenza (Flu) Antiviral Drugs and Related Information

Fiona Havers, MD, MHS, is a medical officer for the Influenza Prevention and Control Team, Epidemiology and Prevention Branch, Influenza Division, within CDC's National Center for Immunization and Respiratory Diseases. Dr Havers earned her doctor of medicine degree from the University of Washington in 2007 and completed training in internal medicine and infectious diseases at the Johns Hopkins University. She obtained a master's of health science in epidemiology from the Johns Hopkins Bloomberg School of Public Health. Dr Havers also completed the Epidemic Intelligence Service training in the Influenza Division at CDC and is board certified in internal medicine and infectious diseases.

While at CDC, Dr Havers' research interests have focused on the epidemiology, prevention, and treatment of influenza. Her research includes studies on the impact of seasonal influenza on children with neurologic disorders and on respiratory viruses in children in Bangladesh. She also assisted the Chinese government in the outbreak investigations of a novel avian influenza in China in 2013 and assisted in the investigation of a novel influenza virus circulating in the Midwest in 2012. Her current primary research focuses on influenza antiviral treatment as well as influenza vaccine effectiveness.