Recommendations for immunocompromised people, such as hemodialysis patients, are different than those for immunocompetent people. Hemodialysis patients who do not respond to an initial vaccine series should be revaccinated with two to four additional doses of HepB (depending on the brand). Hemodialysis patients are considered immune as long as they have adequate anti-HBs (at least 10 mIU/mL). For hemodialysis patients who have responded with adequate anti-HBs (postvaccination testing should be done 1 to 2 months after the vaccine series) to HepB vaccination, no HBsAg testing is needed but anti-HBs should be done annually. If anti-HBs declines below 10 mIU/mL, a booster dose of HepB should be given and annual anti-HBs testing should be continued. Retesting immediately after the booster dose is not necessary.