RT Journal Article SR Electronic T1 Influenza vaccination may have only minimum or no effect on COVID-19 in the aged population JF BMJ Global Health JO BMJ Global Health FD BMJ Publishing Group Ltd SP e010332 DO 10.1136/bmjgh-2022-010332 VO 7 IS 11 A1 Yao, Lan A1 Graff, J Carolyn A1 Gu, Weikuan A1 Sun, Dianjun YR 2022 UL http://gh.bmj.com/content/7/11/e010332.abstract AB