In general, vaccines are regarded safe since such substance is not suspected to give an up-regulation of the heme biosynthesis as a direct effect. However, some vaccines can cause a reaction with high fever persisting over days as a side effect. It is possible that this side effect can trigger an acute porphyric attack in the same way as infections are known to. Vigilance is therefore motivated when administrating a vaccine known to cause reactions with fever.

Fever is reported as a very common side effect the pneumococcus vaccine. Common adverse reactions of the pneumococcus vaccine that can be confused with an acute porphyric attack are nausea and vomiting. These side effects may potentially be porphyrinogenic if leading to a decrease in carbohydrate intake.

The active substances in the pneumococcus vaccine are conjugates of protein and polysaccharides and with regards to its pharmacokinetics it has no conceivable porphyrinogenic effects.

Pneumococcal capsular polysaccharides of different serotypes conjugated to tetanus toxoid-, diphtheria toxoid- and haemophilus influenza carrier protein.

The pneumococcus, purified polysaccharides antigen conjugated vaccine is indicated for immunization to prevent disease caused by Streptococcus pneumoniae in infants and children under five. It is administered by intramuscular injections, in infants usually according to a three or four dose schedule and in children over 12 months two doses are recommended.

The pneumococcus vaccine is not metabolized by the cytochrome P450 system.