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  • Hepatitis B
  • For Adults (Including HBV Screening)

What do I do if an adult patient has documentation of one dose of HepB vaccine of unknown type a few years ago, but never finished the series?

If the vaccine type is unknown, but you have documentation, simply pick up the series where you left off and give dose 2 now—you never have to restart the vaccine series. The patient will need a total of three doses since the only 2-dose series option is for Heplisav-B. If you use Heplisav-B, complete the vaccination series by giving a dose now and a second Heplisav-B dose at least 4 weeks later. If you use any other HepB vaccine product, use a minimum interval of 8 weeks between dose 2 and dose 3 to complete the series. See the CDC’s recommended immunization schedule for details, available at

Last reviewed: July 21, 2023

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