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  • Hepatitis A
  • Administering Vaccines

What happens if dose #2 of HepA vaccine is delayed?

You do not need to start the series over again. The immunogenicity of 1 dose of HepA vaccine is 94% to 100%; studies have shown persistent protection from a single dose lasting more than 10 years. To ensure optimal long-term protection it is important to administer the second dose.

Last reviewed: June 25, 2023

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