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  • Hib (Haemophilus Influenzae Type B)
  • Scheduling & Administration

If a dose of Hib vaccine was given by mistake to a 2-week-old, should further doses of Hib vaccine be given?

Limited data suggest that Hib vaccine given before 6 weeks of age may induce immunologic tolerance to Hib antigen and reduce the response to subsequent doses. As a result, Hib vaccine should not be given earlier than 6 weeks of age. However, if a dose was administered before 6 weeks of age, it should not be counted as part of the Hib series. A full series of 3 or 4 doses, depending on the product used, should be started at 2 months of age as usual. No special protocol or testing is recommended for children who received a dose of Hib vaccine before 6 weeks of age.

Last reviewed: July 31, 2022

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