For the vaccine to become a viable option as a commercial product, it must be manufactured on a large scale with appropriate processing to meet the demands of the regulatory requirements of safety and efficacy. Currently the DISC-HSV is propagated in the CR2 cell line. The CR2 cell line is an adherent cell and therefore routine culture was performed in roller bottle cultures. Whilst this method of cell growth and virus production is suitable for development work it is not a desirable system for the manufacture of the virus on a larger scale. The use of microcarriers as a support for anchorage-dependent cells has been reported previously (Hu et al., 1985; Van Wezel, 1973) . Anchorage-dependant cell lines have been cultured to produce a variety of viruses on a large scale (Talbot et al., 1989; Lesko et al., 1993; Baijot et al., 1987; Meignier, 1978) . Some cell lines such as Vero and MRC5 have been propagated on microcarriers to produce human viral vaccines (Fabry et al., 1989; Griffiths et al., 1980; Montagnon et al., 1981) . Griffiths et al. (1982) have demonstrated HSV-2 production from cells cultured on low (2 g l −1 ) concentrations of Cytodex microcarriers. The yields obtained were ten-fold lower when compared to those achieved from a roller bottle system. It was hoped that our current microcarrier system would produce equivalent productivity when compared to the standard roller bottle process.