Abstract
Modified vaccinia virus Ankara (MVA) is the vector of choice for human and veterinary applications due to its strong safety profile and immunogenicity in vivo. The use of MVA and MVA-vectored vaccines against human and animal diseases must comply with regulatory requirements as they pertain to environmental risk assessment, particularly the characterization of potential adverse effects to humans, animals and the environment. MVA and recombinant MVA are widely believed to pose low or negligible risk to ecosystem health. However, key aspects of MVA biology require further research in order to provide data needed to evaluate the potential risks that may occur due to the use of MVA and MVA-vectored vaccines. The purpose of this paper is to identify knowledge gaps in the biology of MVA and recombinant MVA that are of relevance to its hazard characterization and discuss ongoing and future experiments aimed at providing data necessary to fill in the knowledge gaps. In addition, we presented arguments for the inclusion of uncertainty analysis and experimental investigation of verifiable worst-case scenarios in the environmental risk assessment of MVA and recombinant MVA. These will contribute to improved risk assessment of MVA and recombinant MVA vaccines.
Highlights
Modified vaccinia virus Ankara (MVA) was originally generated by serial passages of chorioallantois Vaccinia virus Ankara (CVA) in chicken embryo fibroblast cells (CEF)
Since MVA is subjected to selection pressure during production of a high titer virus stock intended for vaccination, it is essential to examine the genome stability of the virus across master seed virus (MSV) + 1 to MSV + 5 in human cell lines and in immune-competent and immune-compromised animal models
Even when recombinant poxvirus vaccines are released in areas where some knowledge exists on the characteristics and occurrence of naturally circulating relatives, no systematic study has been undertaken post release to monitor the occurrence of potential adverse effect due to the interactions between genetically modified poxvirus vaccines and naturally circulating OPVs
Summary
Vaccines and vaccine vectors are termed genetically modified (GM) if recombinant gene technology is used to create the vaccine or vector. Recombinant AdV vectors have the advantage of high transduction efficiency, a high level of transgene expression, broad cell tropism and the ability to infect both dividing and non-dividing cells [5]. Retrovirus and AAV vectors provide long-term gene expression and they are not plagued with pre-existing immunity. Their package size is limited to 4.5 and. SeV infects human epithelial cells efficiently and can be administered intranasally This reduces the influence of pre-existing immunity compared to intramuscular administration [13]. These advantages/benefits of the various GMVs are being exploited in improving virus-based GM vaccines, while efforts are underway to reduce their limitations
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
