Hospitalized patients with flu need Tamiflu the day they're admitted, CDC says

Starting Tamiflu upon hospital admission can slash flu deaths by 40% compared with delaying treatment for two to five days, a new study from the Centers for Disease Control and Prevention (CDC) suggests.

Tamiflu (generic name oseltamivir) is one of four antiviral drugs that is currently FDA approved to treat the flu, or influenza. The drug targets two of the most common types of flu viruses — influenza A and B — and works by inhibiting a protein on the surface of the viruses that enables them to replicate within host cells.

The CDC and the Infectious Diseases Society of America recommend that patients who are hospitalized with a suspected or confirmed case of influenza start taking flu antivirals as soon as possible. However, until now, the extent to which earlier treatment improves patients' outcomes was not completely clear.

In a study published Aug. 22 in the journal Clinical Infectious Diseases, CDC researchers examined data from more than 26,000 adults in 13 U.S. states who'd been hospitalized with flu at some point between 2012 and 2019. Each patient's infection was confirmed with a laboratory test, and all had been diagnosed with pneumonia — a potentially deadly complication of influenza. The median age of those hospitalized was 71 years old, which aligns with the fact that people ages 65 and up have the highest rates of severe flu each season.

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Nearly all of the patients — 99.7% — were treated with Tamiflu at some point during their visit. Approximately 60% of those patients started antiviral treatment on the day they were admitted to hospital, 30% were treated the day after, and about 10% were treated between the second and fifth day after admission. The study did not investigate why treatment was delayed in the latter cases.

Overall, the researchers found that patients in that last group were 40% more likely to die of any cause within a month of their hospital admission, compared with those who began treatment the first day.

Delaying by just one day was associated with a 14% increased risk of death, compared with first-day treatment, the team found.

For every additional day a patient didn't receive antiviral treatment, their risk of experiencing severe outcomes other than death — such as being admitted to the intensive care unit or requiring mechanical ventilation to breathe — also increased.

"These findings reinforce the importance of starting influenza antiviral treatment as soon as possible for all patients hospitalized with confirmed or suspected influenza," Dr. Mark Tenforde, lead study author and a medical officer at the CDC, told Live Science in an email.

The study authors acknowledged several limitations of their analysis that may have skewed the results. They didn't account for differences in the amount of time that patients were sick before they were admitted to the hospital, so it's possible that some arrived with much more severe disease than others. However, patients from different groups generally shared similar baseline characteristics, for example in terms of their age, race and underlying health conditions, including asthma and heart disease.

In addition, the study authors considered the risk of death from any cause, meaning it's possible the data captured some deaths that were not directly related to flu — say, cancer.

Nevertheless, these findings support previous research, published in 2015, that suggested that early antiviral treatment reduces the death rate among hospitalized patients with pneumonia from flu.

In an associated statement, the CDC cautioned that, although drugs like Tamiflu are important for treating and preventing flu after a likely exposure, they should not be used as a substitute for an annual vaccine. Flu shots are considered the best way to reduce the risk of flu-related medical visits, hospitalizations and death, as well as the potential worsening of other medical conditions after flu.

This article is for informational purposes only and is not meant to offer medical advice.

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