Science has struggled to determine if antiviral drug Tamiflu is effective or not; one study found it’s effective in single, double doses, while another found it may cause more harm than good. The latest research on the subject comes from the University of Michigan — and it fuels the pro side of the debate.

This particular study sets itself apart because it’s the first patient-level analysis of how well this drug works, study co-author Dr. Arnold Monto said in a press release. According to Monto, conducting research on those infected and not infected with flu dilutes the positive effect in treatment. So they conducted a meta-analysis of data from all published and unpublished clinical trials between the years 1997 and 2001. These trials included data for more than 4,300 patients, as well as Tamiflu manufacturer Roche.

The most prevalent strain of flu was H3N2, the very strain spreading throughout the United States this year. More than half of patients were being treated with Oseltamivir, which is marketed as Tamiflu. This type of drug works to block the enzyme activity in influenza Type A and B viruses; H3N2 is considered type A.

When prescribed the normal, twice-a-day dose of 75 milligrams, the duration of illness decreased by 21 percent within 36 hours of developing at least two flu symptoms. Researchers also found Oseltamivir reduced the risk of "respiratory tract infections requiring antibiotics, like pneumonia," plus "hospital admissions by 63 percent."

In other words, researchers found the antiviral shortens the duration of symptoms by about one day, including common, residual respiratory infections. But the findings weren’t all positive. Like the majority of studies done in the past, the drug increased side effects, such as nausea (3.7 percent) and vomiting (4.7 percent).

Beyond medication, some studies show a lifestyle intervention can rival the pharmaceutical kind. This includes avoiding close contact with people who are sick; frequent hand-washing; avoiding touching your eyes, nose, and mouth; and cleaning areas contaminated with germs

Though the Centers for Disease Control and Prevention said this year's flu vaccine is only 23 percent effective, it can still prevent hospitalizations and death. Perhaps an antiviral, like Tamiflu, will work, too. But be wary of the side effects — and don't assume you have to resort to drugs at all in order to find flu relief.

Source: Monto A, et al. Study shows Tamiflu gets patients back on their feet faster, reduces flu complications. The Lancet. 2015.