As flu season approaches, doctors are offering a new vaccination that will cover four different strains of flu.
However, only 30 million of the four strain vaccinations will be available. The remaining 140 million vaccinations will only cover three types of flu.
Scientists report they have also found a common strain in all flu viruses.
British researchers have discovered a cell called CD8 T in healthy immune systems, which is thought to fight of flu viruses, according to a report from CBS News.
That discovery could help in creating a universal flu vaccine in the next five years.