> https://www.cidrap.umn.edu/news-perspective/2017/02/studies-shed-light-effects-serial-flu-shots-current-vaccines-benefits https://www.cidrap.umn.edu/news-pers

> https://www.cidrap.umn.edu/news-perspective/2017/02/studies-shed-light-effects-serial-flu-shots-current-vaccines-benefits https://www.cidrap.umn.edu/news-perspective/2017/02/studies-... Some years it nets highly negative efficacy depending on your previous years vaccination (see 2014 flu).