A model for developing countries of mass serological survey of children vaccinated against diphtheria and tetanus

Immunogenicity and reactogenicity of two diphtheria-tetanus-whole cell pertussis vaccines in Iranian pre-school children, a randomized controlled trial

The present study was undertaken to compare the immunogenicity and reactogenicity of two diphtheria-tetanus-whole cell pertussis (DTwP) vaccines administered to Iranian preschool children. In this randomized, double-blind and multicenter prospective study, 672 children aged 4-6 y were administered with either a local DTwP vaccine (DTwP-Local) (n = 337) or a commercial vaccine (DTwP-Pasteur) (n = 335). All subjects received DTwP vaccine at 4-6 y of age, following the national immunization schedule of Iran. Blood samples were collected before and 2-4 weeks after the vaccination. Immunogenicity of each vaccine was assessed by ELISA using commercial kits. Reactogenicity was assessed by the parents for seven days post-booster using diary cards. The geometric mean titers (GMTs) of the antibodies induced against diphtheria and tetanus by DTwP-Local were 7.7 and 9.4 IU/ml and those of DTwP-Pasteur were 8.2 and 8.6 IU/ml, respectively. There was no significant difference between the immunogenicity of the two vaccines against diphtheria and tetanus. The GMTs of antibodies produced against pertussis were 30.2 EU/ml for DTwP-Local and 47.9 EU/ml for DTwP-Pasteur vaccines (p<0.001). Pain and fever (axillary temperature>37.5°C) were the most frequent local and systemic reactions observed after the vaccination. All local and systemic reactions observed after vaccination were significantly higher in subjects immunized with DTwP-Local vaccine. Immunogenicity against diphtheria and tetanus was similar for the two vaccines, but immunogenicity of the local vaccine against pertussis was significantly less efficient than that of DTwP-Pasteur. This difference and the higher side effects of the DTwP-Local vaccine could be due to the bacterial strain or the preparation or formulation protocol of the local pertussis vaccine.

[Quantification of diphtheria antibodies in guinea pigs. I. Persistence of serum antibody-levels in animals inoculated with a dose of diphtheria toxoid]

Foi estudado o comportamento da cinética de anticorpogénese em cobaias inoculadas com uma dose de toxóide diftérico precipitado pelo alúmen. Paralelamente, foi estudada a dinâmica da imunidade passiva naturalmente transmitida aos filhotes. Em cobaias vacinadas com uma dose de antígeno, foi verificado que a síntese de antitoxina diftérica persiste, em títulos detectáveis, até 36 meses após. Os anticorpos transferidos, passivamente, da mãe vacinada para os filhotes atingiram, nestes, concentrações plasmáticas superiores, sendo que a imunidade perdurou em títulos detectáveis até cerca de três meses de idade dos mesmos.

[Diphtheria. Immune status of an urban infant population of São Paulo, SP, Brazil]

A verificação do teor de anticorpos antidiftéricos provenientes de 130 crianças de 7 a 10 anos de idade, do município de São Paulo, Brasil, revelou 31, 14 e 5% de indivíduos susceptíveis nas idades de 7, 8 e 9 anos, respectivamente. Todas as crianças de 10 anos de idade apresentaram proteção contra a difteria, revelando teor de antitoxina circulante em níveis superiores a 0,01 UI/ml. O teor médio de antitoxina diftérica encontrada variou de 0,0385 a 0,1315 UI/ml de soro, na população examinada.