Serial passage

Serial passage is the process of growing bacteria or a virus in iterations. For instance, a virus may be grown in one environment, and then a portion of that virus population can be removed and put into a new environment. This process is repeated with as many stages as desired, and then the final product is studied, often in comparison with the original virus.

This sort of facilitated transmission is often conducted in a laboratory setting, because it is of scientific interest to observe how the virus or bacterium that is being passed evolves over the course of the experiment. In particular, serial passage can be quite useful in studies that seek to alter the virulence of a virus or other pathogen. One consequence of this is that serial passage can be useful in creating vaccines, since scientists can apply serial passage and create a strain of a pathogen that has low virulence, yet has comparable immunogenicity to the original strain.^[1] This can also create strains that are more transmissible in addition to lower virulence, as demonstrated by A/H5N1 passage in ferrets.^[2]