MerckVaccine Division recently announced standardization of its hepatitis B vaccine (Recombivax) dosage for all children 0-19 years of age. Merck will discontinue production of this vaccine in 2.5 mcg/0.5 mL vials. The change is being made to avoid the occasional confusion that occurred due to the different recommendations between infants born to women who were chronic hepatitis B surface antigen carriers and infants born to women who were hepatitis B surface antigen negative and not because of problems with immunogenicity of the 2.5 mcg dose.
All children 0 to 19 years of age who receive the Merck vaccine should receive 5 mcg of vaccine in 0.5 mL, regardless of maternal hepatitis B antigen status. Infants born to chronic carrier mothers should also receive hepatitis B immune globulin (HBIG) at birth. Children who have received the complete three dose series of 2.5 mcg/dose of the Merck vaccine do not need to receive any additional doses of vaccine. Children who received one or two of the 2.5 mcg doses should complete the series with either the 2.5 mcg or 5 mcg dose of the vaccine.