A Virus

A virus is an ultramicroscopic infectious organism that, having no independent metabolic activity, can replicate only within a cell of another host organism. A virus consists of a core of nucleic acid, either RNA or DNA, surrounded by a coating of antigenic protein and sometimes a lipid layer surrounds it as well. The virus provides the genetic code for replication, and the host cell provides the necessary energy and raw materials. There are more than 200 …

…may never be synthesized. The kind of research needed to develop a modified live virus vaccine simply could not be done, given the scope of the problem. That is, only a few people would be working in labs who would need to be vaccinated, and a vaccine might want to stockpile in the event of an epidemic. Nevertheless, these are not the scale of circumstances under which the development of a vaccine could be afforded.