An evaluation of serious
neurological disorders following immunization: a comparison of
whole-cell pertussis and acellular pertussis
vaccines.
Geier DA, Geier MR.
MedCon,
Inc., Silver Spring, MD 20905, USA.
Serious neurological
disorders reported following whole-cell pertussis in comparison to
acellular pertussis vaccines were evaluated. The Vaccine Adverse Events
Reporting System (VAERS) was analyzed for Emergency Department (ED)
visits, life-threatening reactions, hospitalizations, disabilities,
deaths, seizures, infantile spasms, encephalitis/encephalopathy, autism,
Sudden Infant Death Syndrome (SIDS) and speech disorders reported with
an initial onset of symptoms within 3 days following whole-cell
pertussis and acellular pertussis vaccines among those residing in the
US from 1997 to 1999. Controls were employed to evaluate potential
biases in VAERS. Evaluations as to whether whole-cell and acellular
vaccines were administered to populations of similar age and sex were
undertaken because these factors might influence the study's results.
Statistical increases were observed for all events examined following
whole-cell pertussis vaccination in comparison to acellular pertussis
vaccination, excepting cerebellar ataxia. Reporting biases were minimal
in VAERS, and whole-cell and acellular pertussis vaccines were
administered to populations of similar age and sex. Biologic mechanisms
for the increased reactogenicity of whole-cell pertussis vaccines may
stem from the fact that whole-cell pertussis vaccines contain 3,000
different proteins, whereas DTaP contains two to five proteins.
Whole-cell pertussis vaccine contains known neurotoxins including:
endotoxin, pertussis toxin and adenylate cyclase. Our results, and
conclusions by the US Institute of Medicine, suggest an association
between serious neurological disorders and whole-cell pertussis
immunization. In light of the presence of a safer and at least equally
efficacious acellular pertussis vaccine alternative, the Japanese and US
switch to using acellular pertussis vaccine seems well justified. Other
countries using whole-cell pertussis-containing vaccines should consider
following suite in the near future.