Antibiotics May Have Been Wrongly Prescribed for Influenza, CDC Finds

influenza, bird flu mutation
This digitally-colorized negative-stained transmission electron micograph (TEM) shows a number of influenza A viruses. H1N1 is a strain of influenza A. (Image credit: CDC/ F.A. Murphy)

During the 2013 flu season, more people needed antiviral medications than got them, and antibiotics were inappropriately given to a large proportion of patients with influenza (a viral disease that is not helped by taking antibiotics), according to a new study.

The researchers found that nearly 30 percent of the flu patients who were treated during the 2012-2013 influenza season may have been prescribed unnecessary antibiotics instead of antiviral therapy.

The new study is based on medical information from nearly 6,800 patients in five U.S. states. The researchers looked at whether the patients who were at high risk of developing serious complications from the flu received antiviral medications as recommended. [6 Flu Vaccine Myths]

The results showed that antiviral and antibiotic medications were prescribed inappropriately. Less than 20 percent of patients with flu symptoms who could have had benefited from antiviral medication because they were at high risk of developing complications actually received the medication. Among patients who were confirmed to have had influenza through laboratory tests, 16 percent were prescribed antivirals.

In contrast, antibiotics were prescribed more frequently, with 30 percent of lab-confirmed influenza patients receiving one of the three antibiotics the researchers looked for, according to the study published today (July 17) in the journal Clinical Infectious Diseases.

The findings suggest that during 2012–2013 flu season, clinicians prescribed antiviral medications to a relatively small percentage of patients in the clinic, for whom the medications were recommended, and missed potential opportunities to prevent more serious complications in these patients, the researchers said.

The Centers for Disease Control and Prevention recommends using antiviral medication to treat flu patients who are at higher risk for developing serious complications, for example, all hospitalized patients who are suspected to have influenza, young children, people ages 65 years and older, pregnant women, and people with certain medical conditions, such as asthma and heart disease. Early treatment with antivirals reduces the patient's risk of developing complications.

Seasonal influenza results in thousands of hospitalizations in the United States each year and can cause even more serious outcomes. In the 2012-2013 flu season, 64 children died from the flu between September 2012 and February 2013. The CDC recommends yearly vaccination as the best defense against seasonal influenza.

In the new study, Dr. Fiona Havers and a team from the CDC and several other institutions examined prescription records, looking for two influenza antiviral drugs (oseltamivir and zanamivir) and three common antibiotics (amoxicillin-clavulanate, amoxicillin and azithromycin).

Of the 6,766 patients in the study, 1,825 patients were tested and confirmed to have influenza, and also had available medical records stating whether they had received an antibiotics prescription. Thirty percent, or 540 of these patients, had received an antibiotic, the researchers found.

About 1,020 of the patients with flu symptoms were considered at high risk for influenza complications. Less than 200 of these patients (19 percent) received antivirals.

When the researchers focused on the patients who were confirmed to have influenza and were at high risk of complications, they found that only 28 percent of them received an antiviral medication prescription and 24 percent received an antibiotic.

Antibiotics cannot treat influenza, which is caused by a virus. While some of the antibiotics may have been appropriate because patients may have also had bacterial infections in addition to influenza, it is likely most were unnecessary, and potentially contributed to the growing problem of antibiotic resistance, the researchers said.

The findings highlight the need to educate clinicians about the appropriate use of antivirals and antibiotics in patients who have symptoms of influenza, the researchers said.

"Continuing education on appropriate antibiotic and antiviral use is essential to improve health care quality," the researchers wrote in their study.                                            

Email Bahar Gholipour. Follow Live Science @livescience, Facebook & Google+. Originally published on Live Science.

Bahar Gholipour
Staff Writer
Bahar Gholipour is a staff reporter for Live Science covering neuroscience, odd medical cases and all things health. She holds a Master of Science degree in neuroscience from the École Normale Supérieure (ENS) in Paris, and has done graduate-level work in science journalism at the State University of New York at Stony Brook. She has worked as a research assistant at the Laboratoire de Neurosciences Cognitives at ENS.