VAC2VAC is a wide-ranging collaborative research project funded by IMI2 which aims to develop and validate quality testing approaches for both human and veterinary vaccines using non-animal methods. The initiative that started on 1 March 2016 aims to provide the data to support the "Consistency Approach" for quality control of established vaccines, where current quality control approaches are often relying on in vivo methods.

VAC2VAC is a public-private consortium of twenty partners, involving experts from veterinary and human vaccine industry in a partnership with official medicines control laboratories, academia, translational research organisations, and vaccinology alliances. To achieve their goal, the project partners will develop, optimise and evaluate physico-chemical and immunochemical methods, cell-based and other assays for routine batch quality, safety and efficacy testing of vaccines. This will be done in collaboration and consultation with regulatory agencies. The ultimate goal of the project is to develop tests and approaches that will allow acceptance of the "Consistency Approach" for established vaccines by the regulatory agencies and thereby significantly reducing in the future the use of animals for batch testing in routine vaccine production.


Check new publications of VAC2VAC:

Variability of in vivo potency tests of Diphtheria, Tetanus and acellular Pertussis (DTaP) vaccines

Coen A.L. Stalpers, Irene A. Retmana, Jeroen L.A. Pennings, Rob J. Vandebriel, Coenraad F.M. Hendriksen, Arnoud M. Akkermans, Marcel H.N. Hoefnagel


For batch release of legacy vaccines such as DTaP, in vivo potency release assays are required. We quantified the variability of in vivo potency release assays for four DTaP (Diphtheria, Tetanus, acellular Pertussis) products of different manufacturers. With their large CV (Coefficients of Variance) ranging from 16% to 132%, these in vivo assays are of limited value to ensure their potency is consistent and similar to the clinical batches used for the marketing authorisation. Our data show that, although individual potency test results show high variability, the DTaP batches are manufactured with great consistency, because repeated potency testing yields similar averages for the different batches. The economic impact of variability of in vivo tests is significant since it may result in the need for greater amount of antigen than may be required or for repeating a test.


For monitoring the consistency of potency, in vitro assays are superior to in vivo assays. Animal-free potency determination is common practice for newly developed vaccines under modern GMP quality systems. However, replacement of in vivo potency tests for legacy vaccines like DTaP is challenging and would require a ‘reverse characterisation’ strategy in which the antigens are further characterised at the level of drug substance and drug product to identify critical quality attributes (CQA) that can be tested with in vitro assays. Based on these an updated set of release tests without animal tests can be proposed. Our data can serve as benchmark for the innovative methods. Download full article

Human plasmacytoid dendritic cells at the crossroad of type I interferon-regulated B cell differentiation and antiviral response to tick-borne encephalitis virus

Marilena P. Etna, Aurora Signorazzi, Daniela Ricci, Martina Severa, Fabiana Rizzo, Elena Giacomini, Andrea Gaggioli, Isabelle Bekeredjian-Ding, Anke Huckriede, Eliana M. Coccia

PloS Pathogens

The Tick-borne encephalitis virus (TBEV) causes different disease symptoms varying from asymptomatic infection to severe encephalitis and meningitis suggesting a crucial role of the human host immune system in determining the fate of the infection. There is a need to understand the mechanisms underpinning TBEV-host interactions leading to protective immunity. To this aim, we studied the response of human peripheral blood mononuclear cells (PBMC) to the whole formaldehyde inactivated TBEV (I-TBEV), the drug substance of Encepur, one of the five commercially available vaccine. Immunophenotyping, transcriptome and cytokine profiling of PBMC revealed that I-TBEV generates differentiation of a sub-population of plasmacytoid dendritic cells (pDC) that is specialized in type I interferon (IFN) production. In contrast, likely due to the presence of aluminum hydroxide, Encepur vaccine was a poor pDC stimulus. We demonstrated I-TBEV-induced type I IFN together with Interleukin 6 and BAFF to be critical for B cell differentiation to plasmablasts as measured by immunophenotyping and immunoglobulin production. Robust type I IFN secretion was induced by pDC with the concerted action of both viral E glycoprotein and RNA mirroring previous data on dual stimulation of pDC by both S. aureus and influenza virus protein and nucleic acid that leads to a type I IFN-mediated sustained immune response. E glycoprotein neutralization or high temperature denaturation and inhibition of Toll-like receptor 7 signalling confirmed the importance of preserving the functional integrity of these key viral molecules during the inactivation procedure and manufacturing process to produce a vaccine able to stimulate strong immune responses. Download full article