[Vaccines pharmacovigilance]. / Pharmacovigilance des vaccins.

ABSTRACT

The pharmacovigilance of vaccines has the particularity of concerning medications with a preventative target, used in healthy subjects, who are often young. Their individual benefit is deferred and unknown, whereas their risk is immediate. Certain undesirable effects are linked to the antigen of live attenuated vaccines (post-MMR lymphocytic meningitis). Other non-specific effects are linked to other different components of the vaccines (macrophage and aluminium myofasciitis). Undesirable events susceptible to being due to the vaccination are identified and managed according to standardised procedures of pharmacovigilance, that is to say, based on "spontaneous notification", generation of an alert, confirmed or not by studies of pharmaco-epidemiology. The studies of pharmaco-epidemiology have made evident oedematous reactions with cyanosis or purpura, with the vaccines containing the Haemophilus b valence, and the absence of an association with sudden death of the newborn; have excluded the existence of an elevated risk of demyelinisation or auto-immune disease associated with vaccination against hepatitis B, without being able to exclude a slight risk; go against the finding of an association between Crohn's disease and/or autisim and the MMR vaccination. Only their frequently encountered undesirable effects are well identified at the moment of commercialisation. Post-marketing surveillance of vaccines (declaration to the regional pharmacovigilance centres) allow the detection of possible rare and serious effects and the evaluation of the real vaccination risk. Thus it must be intensive and systematic.