Influenza viruses have been notoriously hard to treat. Vaccines are far from foolproof. That’s because the viruses often mutate and even when there is a good match between the flu shot and the circulating pathogens, the vaccine is only partially protective. Available antiviral medications such as Tamiflu and Relenza have been controversial because their effectiveness has been challenged.
Now, a new injectable drug called peramivir has shown surprising benefit against flu symptoms. In two studies more than 400 volunteers who received the shot within two days of the first flu symptoms recovered more quickly than those who received placebo shots. It remains to be seen whether the FDA will approve this new antiviral and if it lives up to expectations.
Because the drug is administered intravenously, it may well be reserved for hospitalized patients whose health would be seriously threatened by influenza.