Lacombe K, Abdoulaye Y, Simondon K, Pinchinat S, Simondon F. Risk factors for acellular and whole-cell pertussis vaccine failure in Senegalese children. Vaccine, 2004. In press.
UR024, Institut de Recherche pour le Développement (IRD), 911, avenue Agropolis, BP 64501, 34394 Montpellier Cedex 5, France.
Although use of acellular pertussis vaccine was associated with a higher
rate of vaccine failure than that of whole-cell vaccine in the Senegal
Pertussis Trial conducted in 1990-1994 on 4189 children, risk factors
for vaccine failure regarding exposure and susceptibility to pertussis
have not been studied so far. Pertussis occurred in 346 vaccinated children.
Three factors were found to be associated with vaccine failure, independently
of the vaccine type, namely the degree of exposure, birth rank, and time
since weaning. In the whole-cell vaccine group, the risk of failure increased
with birth rank [RR = 2.95 (1.51-5.75)] and was higher in non stunted
children [RR = 1.43 (1.05-1.94)]. In the acellular vaccine group, the
risk of failure increased with age at exposure to B. pertussis [RR =
2.24 (1.21-4.12) after 18 months of age] and the degree of exposure [RR
= 2.14 (1.17-3.93) when the child shared the hut of an index case]. These
results highlight the influence of environmental factors on the success
of pertussis vaccination. However, they do not explain the shorter duration
of protection provided by the acellular vaccine compared to the whole-cell
vaccine which persist after controlling and thus might be related to
the nature of the vaccine.