Study: Antibiotics don't reduce risk of death from viral respiratory infections

Intravenous therapy drip

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Prescribing antibiotics for hospital patients with viral respiratory infections does not appear to have any protective effect, according to a study to be presented at next month's European Congress of Clinical Microbiology and Infectious Diseases (ECCMID).

In fact, the study by researchers in Norway found that patients with viral respiratory infections who received antibiotics at any point during their hospitalization were more than twice as likely to die as those who didn't receive antibiotics. The authors of the observational study say the findings provide further evidence in support of more judicious antibiotic use in patients hospitalized with viral respiratory infections.

Nearly two-thirds of patients with viral infections received antibiotics

The study included adult patients admitted to Norway's Akershus University Hospital from 2017 through 2021 who had a nasopharyngeal or throat swab that was positive for influenza, respiratory syncytial virus (RSV), or SARS-CoV-2 on admission. The researchers looked at which of those patients received antibiotics, calculated antibiotic days of therapy (DOT) for each patient, and assessed the impact of antibiotic therapy on survival, with 30-day all-cause mortality as the primary outcome. Patients with bacterial infections were excluded.

The researchers say they wanted to explore the impact of antibiotic use in this cohort because of the high rate of unnecessary antibiotic use observed in COVID-19 patients. Early studies during conducted during the pandemic found that as many as 70% of COVID-19 patients in some countries received antibiotics, in part because of the lack of other treatments but also because of concerns about bacterial co-infections. Yet those studies, and subsequent research, show that fewer than 10% of COVID-19 patients have bacterial co-infections.

Of the 2,111 patients included in the analysis, 935 (44.3%) had influenza, 429 (20.3%) had RSV, and 747 (35.4%) had SARS-CoV-2. A total of 1,321 (63%) received antibiotics for respiratory infection during hospitalization—1,153 upon admission and 168 later in their hospital stay. The 30-day mortality rate among the entire cohort was 8%; of the 168 patients who died within 30 days, 119 received antibiotics on admission, 27 received them later in their stay, and 22 did not receive antibiotics.

Lessons from the Covid-19 pandemic suggest that antibiotics can safely be withheld in most patients with viral respiratory infections, and that fear of bacterial co-infections may be exaggerated....Our new study adds to this evidence.

After adjusting for virus type, age, sex, severity of disease at baseline, and comorbidities, the researchers found that patients prescribed antibiotics at any point of their hospitalization were twice as likely to die within 30 days (hazard ratio [HR], 2.10; 95% confidence interval [CI], 1.31 to 3.38). The risk of mortality increased by 3% for each day of antibiotic therapy (HR per DOT, 1.03; 95% CI, 1.01 to 1.05). But antibiotics initiated at admission were not associated with an increased risk of death (HR, 1.16; 95% CI, 0.81 to 1.68).

Although they adjusted for age and disease severity, the authors say the higher mortality among patients who received antibiotics may be explained by the fact that sicker patients and those with more comorbidities were both more likely to be treated with antibiotics and to die. They also note that unreported factors, such as smoking and socioeconomic background, may have played a role.

Nonetheless, antibiotics did not appear to benefit the nearly two-thirds of hospital patients with viral respiratory infections who received them.

"Lessons from the Covid-19 pandemic suggest that antibiotics can safely be withheld in most patients with viral respiratory infections, and that fear of bacterial co-infections may be exaggerated," lead author Magrit Jarlsdatter Hovind, PhD, of Akershus University Hospital and the University of Oslo, said in an ECCMID press release. "Our new study adds to this evidence, suggesting that giving antibiotics to people hospitalized with common respiratory infections is unlikely to lower the risk of death within 30 days." 

Hovind said restricting use of antibiotics in patients hospitalized with flu or other viral respiratory infections could help reduce the risks of antibiotic side effects and help fight antimicrobial resistance.

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