A series of new reports assessed how well antiviral medications worked to prevent and treat the flu.
Two of the studies found the medications shortened hospital stays and lowered the risk of infection in people with high risks. The third study found that starting the medications in a timely fashion can lower the risk of death from flu-related pneumonia.
The first meta-analysis was published Aug. 24 in The Lancet. It covered eight randomized controlled trials of antiviral medications, and sought to determine how well they reduced symptoms and duration of hospitalization in patients with severe influenza. More than 1,400 people who were 36 to 60 years old were included in the studies.
Compared with standard care, there was little or no difference in time to symptom relief with oseltamivir (Tamiflu) or peramivir (Rapivab). The researchers also said these drugs might reduce duration of hospitalization for seasonal influenza but the evidence was of low certainty.
“The effects of all antivirals on mortality and other important patient outcomes are very uncertain due to scarce data from randomized controlled trials,” the authors wrote.
The second report, published Aug. 24 in The Lancet, assessed the use of neuraminidase inhibitors. It included 33 trials of the antivirals zanamivir, oseltamivir, laninamivir (Inavir), baloxavir (Xofluza) amantadine (Symmetrel), and rimantadine (Flumadine), spanning more than 19,000 people between seven to 81 years old.
In the current review, investigators found evidence that zanamivir, oseltamivir, laninamivir, and baloxavir probably lower flu rates in those at high risk for severe illness if taken within 48 hours of exposure to the virus. But the drugs probably don’t reduce rates of symptomatic flu in patients at low risk.
However, they found that rimantadine and amantadine probably have little or no effect on symptomatic seasonal influenza A virus infection.
Zanamivir, oseltamivir, laninamivir, and baloxavir might decrease the risk of symptomatic zoonotic influenza, though the evidence was of low certainty.
In the third study, which was published Aug. 22 in Clinical Infectious Diseases, gauged the risk of death among more than 26,000 adults hospitalized with flu and pneumonia. Almost all were given oseltamivir.
Compared to those starting an antiviral on the day they were infected, those starting on day five were more likely to be admitted to the intensive care unit, go on a ventilator or die within 30 days.
