In fact, using live virus did carry a risk of infection.

In several cases, live virus was recovered from the patient's blood.

The live viruses require animal or human cells as a host for production of more virus.

Volunteers have yet to be exposed to the live virus.

Four monkeys that got the vaccine were injected with the live virus a month later.

In his search, he unearthed bodies but failed to find any live viruses.

The vaccine, given in the second year of life, is made with live, but weakened, viruses.

It is particularly important to check about vaccinations because many of them contain live virus.

None of these people can be given the current vaccine, which uses a live virus.

Mandates strict controls for the use of any live virus at such research facilities.