Question: what is the composition of the current flu vaccine?
Answer: Flu vaccines protect against the three or four viruses (depending on vaccine) that research suggests will be most common. For 2018-2019, trivalent (three-component) vaccines are recommended to contain: A/Michigan/45/2015 (H1N1)pdm09-like virus. A/Singapore/INFIMH-16-0019/2016 A(H3N2)-like virus (updated)