When a new strain of flu takes hold, why does the old strain die out? Why doesn’t it continue making people sick every year? The authors of a new Opinion piece in mBio have an idea. They say the secret’s in the stalk. Novel flu strains arise in those folks unlucky enough to get infected with two different strains at the same time. The two strains get together, share some genes, and have the potential to create a combination that human immune systems haven’t seen before. If it’s virulent, this hybrid flu virus can sweep through the population and create... | Continue »