Review of animal use requirements in WHO biologics guidelines – database of suggested guideline revisions

Original text

Tests in suckling mice: the virulence of different vaccine candidates in mice will depend on the strains of virus and mouse. Novel vaccines that reach the clinical phase of development in many cases were tested for neurovirulence in suckling and adult mice during the preclinical phase of development.

New text

The potential neurovirulence of a new vaccine strain should be assessed during preclinical development and a risk analysis carried out based on available scientific data and information. If molecular consistency has been demonstrated during characterisation, then assessment of neurovirulence may be omitted for subsequent viral seed lots and/or routine manufacturing. For existing products where animal neurovirulence testing is currently prescribed, this test can be waived when safety and genetic stability of the product are sufficiently assured. This can be established by historical / (pre-) clinical, and pharmacovigilance data, and by data generated with nucleic acid amplification and sequencing techniques, to support the molecular consistency of the virus and for the establishment of a link between genetic sequences and in vivo phenotypes. For all products, a risk-based approach should be performed taking into consideration the genetic features and molecular consistency of the strain (sequence evaluated at different manufacturing steps, determined with traditional or new sequencing technologies) and the nature of the vaccine (attenuated, chimeric, genetically modified), to assess whether a neurovirulence assay is required and what animal model is most suitable. If an in vivo assay is scientifically justified, it should be established at what level (Master Seed Lot, Working Seed Lot, monovalent bulk) the test should be performed to avoid unnecessary duplication.

Original text

At the end of the observation period, a fraction of control cells comprising not less than 25% of the total should be tested for the presence of haemadsorbing viruses, using guinea-pig red blood cells.

New text

At the end of the observation period a fraction of culture comprising not less than 25% of the total should be tested for the presence of haemadsorbing viruses, using red blood cells from guinea-pig or other suitable red blood cells. It is not necessary to use red blood cells from multiple species. If the red blood cells have been stored prior to use in the haemadsorption assay, the duration of storage should not have exceeded 7 days and the temperature of storage should have been in the range of 2–8 °C.

Original text

Assays for the attenuation of dengue/yellow fever recombinants and other vaccine viruses, if appropriate, include tests in suckling mice….The test for consistency may be omitted as a routine test once the consistency of the production process has been demonstrated on a significant....number of batches in agreement with the NRA. Where there is a significant change in the manufacturing process, the test should be reintroduced.

New text

A suitable assay for the attenuation of dengue/yellow fever recombinants and other vaccine viruses should be carried out.

Original text

Each filling lot should be tested for unexpected toxicity (sometimes called abnormal toxicity) using a general safety test approved by the NRA. This test may be omitted for routine lot release once consistency of production has been established to the satisfaction of the NRA and when good manufacturing practices are in place. Each lot, if tested, should pass a general safety test.

New text

Original text

A.3.1.1 - Hamsters and gerbils for cell cultures
A.3.1.2 - Rodents for virus propagation in neural tissue
A.3.1.4 - Serum used in cell culture medium

New text

Original text

Suitable tests for detecting viruses in calf or newborn calf serum

New text

A strategy for testing adventitious viruses in vaccines must be developed based on a risk assessment. Relevant culture methods and/or specific molecular biology or broad molecular methods should be part of the overall testing package with the agreement of the NRA. In vivo tests may only be used if the risk assessment indicates that this test provides an additional risk mitigation taking into account the overall testing package.

Original text

Vaccine production shall be based on hantavirus strains associated with human disease. The strains used to produce seed lots shall be approved by the national control authority and shall yield safe and immunogenic vaccines when the vaccine has been inactivated. They shall be identified by historical records, infecticity tests, serological tests and animal responses to inoculation

New text

Vaccine production shall be based on hantavirus strains associated with human disease. The strains used to produce seed lots shall be approved by the NRA and shall yield safe and immunogenic vaccines when the vaccine has been inactivated.

Original text

Tests for adventitious viruses - each virus seed lot shall be tested for adventitious agents after neutralization with a specific anti-hantavirus serum.

New text

A strategy for testing adventitious viruses in vaccines must be developed based on a risk assessment. Relevant culture methods and/or specific molecular biology or broad molecular methods should be part of the overall testing package with the agreement of the NRA. In vivo tests may only be used if the risk assessment indicates that this test provides an additional risk mitigation taking into account the overall testing package.

Original text

The virus content of each single harvest shall be determined, before any purification, by intracerebral injection of suckling mice of two days of age or in sensitive cell cultures.

New text

The virus content of each single harvest shall be determined, before any purification, in sensitive cell cultures. If a cell culture method is not available or suitable an alternative method may be used following approval by the NRA.

Original text

Option (B) - Each of at least 10 mice of two days old is innoculated intracerebrally…..
Option (C) - Suckling mice and hamsters are innoculated with culture fluid…...

New text

Each undiluted bulk suspension shall be tested for inactivation of the virus by an in vitro method approved by the NRA (e.g. immunoassay for hantaviral antigen following inoculation of test sample into a suitable cell culture). If an in vivo inactivation assay is conducted, it should be specifically justified and approved by the NRA.