Also worth noting that strain is not controlled for in this study. The study acknowledges at the end that reinfection may be by different strains. Under the sam

Also worth noting that strain is not controlled for in this study. The study acknowledges at the end that reinfection may be by different strains. Under the same parameters as this study it could be said that flu infection doesn't confer immunity. But, it does, just there are a lot of distinct strains of flu.