Serious Flu Risk Could Be Identified with Genetic Test

In August, a U.S.-Chinese research team pooled the results of four published studies that show among 445 people infected with either swine flu or H5N1 bird flu, those with a variant of a gene called IFITM3 were 24 percent more likely to have suffered a severe infection. Traditionally, those considered most in danger from the flu include individuals over age 65, pregnant women and those with underlying health problems such as asthma. But this new research suggests that many more people in the general population are prone to suffer badly with the flu if they have the variant IFITM3 gene. About one in 400 people carries the IFITM3 gene, which normally encodes a protein that helps the body’s cells resist viral infection. But, the mutated version of the gene impairs the body’s natural defense.

Paul Kellam, an expert in virus genomics at the Wellcome Trust Sanger Institute, says the gene variant could help doctors spot people who are not usually considered a risk, but are genetically susceptible to infection. “You can then start to stratify people ahead of time and prioritize them for vaccination,” he said. Prioritizing people for the flu shot on the basis of their genetics could slash the number of cases of serious illness and save costs on hospital care. In addition, the discovery of the gene variant opens the door to new anti-viral drugs, said Kellam. A different study published in August showed that it might be possible to boost levels of the IFITM3 protein to make people more resistant to the flu.