A trial to compare the reactogenicity and immunogenicity of a reduced antigen content
diphtheria–tetanus–acellular pertussis (dTpa) vaccine with diphtheria–tetanus–whole-cell
pertussis (DTPw) vaccine was conducted in Thailand. Three hundred and thirty children
aged 4–6 years, primed with four doses of DTPw, received a single injection of either dTpa
or DTPw. There was a significantly lower incidence of local and general reactions following
dTpa than DTPw (P< 0.001). One month after vaccination, 99.4 and 100% of all subjects had …

Background. The recent introduction of acellular pertussis vaccines (Pa) offers the possibility
of booster doses in older children and adults. This can be conveniently accomplished by
combining acellular pertussis antigens with diphtheria and tetanus toxoids. However the
optimal dosage for the booster injection has not yet been determined. Objective. To compare
the reactogenicity and immunogenicity of diphtheria–tetanus–acellular pertussis vaccines
(DTPa) with lower antigen contents to a licensed DTPa vaccine when given at 4–7 years of …