Reactogenicity and Immunogenicity at Preschool Age of a Booster Dose of Two Three-Component Diphtheria-Tetanus-Acellular Pertussis Vaccines in Children Primed in Infancy With Acellular Vaccines

Objectives.To determine the reactogenicity and immunogenicity of a fourth dose of 2 three-component acellular pertussis vaccines combined with diphtheria-tetanus-acellular pertussis (DTaP) when administered at preschool age to children primed in infancy with 3 doses of the same DTaP and who had received a diphtheria-tetanus (DT) dose at the age of 12 months.Setting.Local health units of 4 Italian regions.Study Design.Three thousand five hundred twenty-two children, who had been randomized in the first year of life to be immunized with a DTaP vaccine by either SmithKline Beecham or Chiron Biocine, were offered a booster of the same vaccine or, if refusing, a DT vaccine at the age of 5 to 6 y…

A Controlled Trial of Two Acellular Vaccines and One Whole-Cell Vaccine against Pertussis

Background Concern about both safety and efficacy has made the use of whole-cell pertussis vaccines controversial. In some European countries, including Italy, the rate of vaccination against pertussis is low. Methods We conducted a double-blind trial in Italy in which infants were randomly assigned to vaccination at two, four, and six months of age with an acellular pertussis vaccine together with diphtheria and tetanus toxoids (DTP); a DTP vaccine containing whole-cell pertussis (manufactured by Connaught Laboratories); or diphtheria and tetanus toxoids without pertussis (DT). The acellular DTP vaccine was either one containing filamentous hemagglutinin, pertactin, and pertussis toxin ina…

Neuropsychological performance 10 years after immunization in infancy with thimerosal-containing vaccines

OBJECTIVE. Thimerosal, a mercury compound used as a preservative in vaccines administered during infancy, has been suspected to affect neuropsychological development. We compared the neuropsychological performance, 10 years after vaccination, of 2 groups of children exposed randomly to different amounts of thimerosal through immunization. METHODS. Children who were enrolled in an efficacy trial of pertussis vaccines in 1992–1993 were contacted in 2003. Two groups of children were identified, according to thimerosal content in vaccines assigned randomly in the first year of life (cumulative ethylmercury intake of 62.5 or 137.5 μg), and were compared with respect to neuropsychological outcome…

How increased pertussis vaccination coverage is changing the epidemiology of pertussis in Italy.

Abstract The epidemiology of pertussis in Italy is described by using data from the statutory notification system and from seroepidemiology studies. Starting from the 1990s, the incidence of pertussis in Italy has shown a sharp decline and is now at the lowest level ever reached. During this time period vaccination coverage has increased from 88% in 1998 to 95% in 2003. In 1996–97, the prevalence of subjects with levels of IgG antibodies against PT greater than 2 EU/ml was 77.6%. The increase in vaccination coverage will probably change the pattern of disease transmission and increase the number of susceptible adults, unless administration of booster doses to adolescents and adults is consi…

B. Zinka et al., Unexplained cases of sudden infant death shortly after hexavalent vaccination

Analogous IgG subclass response to pertussis toxin in vaccinated children, healthy or affected by whooping cough

The study of antigen specific IgG subclass distribution during disease, or during any other natural or artificial immunisation, can provide useful information on the kind of the immune response and the expected levels of protection. This is particularly true for diseases, such as pertussis in which the mechanisms underlying specific defence are still not completely understood. An investigation was therefore performed to evaluate the IgG subclass response to pertussis toxin (PT) in sera from 89 healthy vaccinated children and 131 vaccinated or unvaccinated children convalescent after a confirmed B. pertussis symptomatic infection. Antibody titres were expressed in arbitrary ELISA units/ml, a…

Reactogenicity of a three-dose pertussis acellular vaccine catch-up in children 21-40 months of age

Abstract The reactogenicity of a three-dose catch-up acellular pertussis (aP) immunization of children at 21–40 months of age was evaluated. Vaccination was well-tolerated: fever ≥38°C was reported after 5% of administered doses and local reactions after 14–15%. The onset of adverse events was not associated with age at vaccination, interval between doses or previous presence of antibodies against pertussis, whereas injection in sites other than the buttock and presence of the same symptom after a previous dose were associated with higher reactogenicity. Because of the good safety profile of primary aP immunization in children >1 year of age, catch-up vaccination campaigns could be consider…

Persistence of protection through 33 months of age provided by immunization in infancy with two three-component acellular pertussis vaccines

Abstract A large, randomized, placebo-controlled clinical trial in Italy on two three-component pertussis vaccines, given as DTaP in infancy, one manufactured by SmithKline and Beecham (SB) and one by Chiron Biocine (CB), found each vaccine to be 84% efficacious through the average age of 24 months. The cohort of children envolled in the trial was followed with unmodified case ascertainment procedures for nine additional calendar months, during which partial unblinding occurred, for the unvaccinated randomized group. For the DTaP groups, the specific vaccine assignment remained double-blinded throughout the entire additional observation period. Pertussis was defined as paroxysmal cough last…

Effect of duration of breastfeeding on neuropsychological development at 10 to 12years of age in a cohort of healthy children

Aim The aim of this article was to explore the effect of duration of breastfeeding on neurocognitive development. Method The long-term effect of breastfeeding on neurodevelopment was examined through a battery of neuropsychological tests in 1403 children (693 females, 710 males; mean age 11y 9mo [SD 6mo], range: 10y 3mo-12y 8mo) who were originally recruited at 6 to 12weeks of age for a clinical trial on acellular pertussis vaccines. An estimated IQ was obtained from scores of the vocabulary, similarities, block design, and coding tests. Breastfeeding data had been prospectively collected throughout the first year of life. Duration of exclusive breastfeeding was defined as the time during w…