Table 3: Potency testing of inactivated rabies vaccines: the NIH test and its variants
| Number of tests required | Mice to be used | Number of animals/ dilution | Number of dilutions | Diluent to be used | Number of vaccinationsa | Interval between vaccinations (days) | Interval between vaccination and challenge (days) | Challenge dose (LD50)b | Observation period after challenge (days) | Criteria for evaluation | |
| Ph. Eur. for human use (38) | - | Female ± 4 weeks 11-15g | Suitablec | 3 | n.s. | 2 | 7 | 7 after second | ~50 | 5-14 | Death or signs of rabies |
| WHO (4) | 2 | 13-16g | >16 | 5 (>3) | PBS | 2 | 7 | 14 after first | 12 < 25 < 50 | > 5-14 | Death |
| Ph. Eur. for veterinary use (33) | - | Female > 4 weeks | > 10 | > 3 | n.s. | 1 | n.a. | 14 | ~50 | 5-14 | Signs of rabies |
| SAM0308.01 (15) | 1 (3, when repeated) | Female CF-1 13-15g | 16 | 5 | PBS | 2 | 7 ± 1 | 14 ± 1 after first | 12-50 | 6-14 | Death or signs of rabies |
| OIE (5) | - | 3-4 weeks | > 10 | n.s. | n.s. | 1 or 2 | 7 if applicable | 14 days later | > 10 | n.s. | n.s. |
| 9CFR 113.209 (7) | 2 | 13-16g | > 16 | 5 (> 3) | PBS | 2 | 7 | 14 after first | 12 < 25 < 50 | > 5-14 | Death |
| Simplified single-dilution test (12) | - | Female | 10 | 1 | - | 1 | n.a. | 14 | ? | 14 | > 80% survival |
aInjection volume: 0.5ml; injection route: intraperitoneal.
bChallenge virus: CVS27; challenge route: intracerebral; injection volume: 0.03ml.
cA suitable number of animals should be used to meet the statistical requirements for a valid test.
n.a. = not applicable; n.s. = not specified; PBS = phosphate-buffered saline.
9CFR = US Code of Federal Regulations, Title 9; NIH = National Institutes of Health; OIE = Office International des Epizooties; Ph. Eur. = European Pharmacopoeia; SAM = Supplemental Assay Method; WHO = World Health Organization.