Ten to 15 years earlier, the researchers had given the study participants a glucose tolerance test, a common test for diabetes. (health.com)
Once this booster is given studies show the duration of immunity anywhere from 8 - 15 years and most likely lifetime. (cruisincavaliers.com)
Although most employers give study leave, a substantial amount of private study is also usually necessary to ensure that all examination stages are successfully passed. (targetjobs.co.uk)