A collaborative assay of the proposed second International Standard for Pertussis Vaccine and of the proposed first British Standard for Pertussis Vaccine

Evaluation of the Potency of the Pertussis Vaccine in Experimental Infection Model with Bordetella pertussis: Study of the Case of the Pertussis Vaccine Used in the Expanded Vaccination Program in Algeria

“…However, each trial gave a significant regression of the response curve of the immunized mice transformed into probit as a function of the log of the vaccine dose used (p ≤ 0.05), and the common slope analysis revealed no significant difference between the preparations of each trial (p > 0.05). Similar results have been reported in several studies [22,35,38,47].…”

“…However, the slight variation recorded in the number of viable organisms of B. pertussis in a LD50 (338.92 ± 111.60), and the number of LD50s of the challenge suspension (324.43 ± 114.68), of the five trials, is essentially explained by the culture conditions of the strain, citing the age of the culture and the quality of culture media used [40,41]. These results are similar to those reported by several other studies [33,35,38]. Also adding that the LD50 could be subject to variations during intracerebral injection, or there could be a loss of some of the bacterial inoculum following the use of a rough-tipped needle [19,21].…”

“…The observation of this variability was coherent with previous studies [19,[34][35][36]. Indeed, the mouse protection test against experimental B. pertussis infection by pertussis vaccine is influenced both by the immunization dose ED50, which corresponds to the efficacy of the vaccine [19,22,37], the virulence of the challenge strain (LD50) of B. pertussis [38] and the strain of mouse used [24,36,39]. All of these factors constitute a source of variability that affects the potency test.…”

Collaborative Study on Test Systems to Assess Toxicity of Whole Cell Pertussis Vaccine

“…Differences in estimated potency between the laboratories often ranged from 4 to 5 and in a few occasions even more than a factor 10. This finding conflicts with the one of Seagroatt and Sheffield, 17 who found largely consistent data in all laboratories. Significant differences (up to factor 6) were also seen at intralaboratory duplicate testing.…”

“…In the HS test, groups of mice (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) were injected intraperitoneally with serial dilutions of the vaccine to be tested. Four to 5 days after injection animals were challenged intraperitoneally with 0⋅5 ml of diluted histamine solution and the number of non-surviving mice in a prescribed observation period was recorded.…”