En utilstrækkelig virkning af vaccinen, som kan medføre, at der ikke opnås beskyttelse mod hepatitis B er også set hos ældre personer, hos flere mænd end kvinder, hos rygere, overvægtige, personer med langvarig sygdom eller personer, der tager visse typer medicin.
A poor response to the vaccine, possibly without achieving protection against hepatitis B, has also been observed in older people, men rather than women, smokers, obese people, and people with long standing illnesses, or people on some type of drug treatments.