RT Journal Article SR Electronic T1 Review: Killed whole-cell vaccines prevent cholera for 2 years JF Evidence Based Medicine JO Evid Based Med FD BMJ Publishing Group Ltd SP 42 OP 42 DO 10.1136/ebm.1999.4.42 VO 4 IS 2 YR 1999 UL http://ebm.bmj.com/content/4/2/42.abstract AB