Phase five is marked by human-to-human spread of the virus into at least two countries in the same area of the world.

VOA: special.2009.05.06

Phase four means that a virus has gained the ability to cause community-level outbreaks.

VOA: special.2009.05.06

The WHO's Phase 5 threat warning signals that a global pandemic could be imminent, but has yet to develop, with human-to-human transmission occurring in many geographical locations.

VOA: standard.2009.04.30

a medium-term phase out of what they call inefficient fossil fuel subsidies, although this would take into account what they call vulnerable groups and their development needs.

VOA: standard.2010.06.27

But it has taken on new urgency,coming one day after the World Health Organization raised its global swine flu alert to Phase 4 on the six-point scale.

VOA: standard.2009.04.28

"But if you look into the Mekong delta, for example in Vietnam, it has shown the 30-year cycle, but the phase and amplitude is going up and then going up like that."

VOA: standard.2009.12.21

The World Health Organization says it needs to see clear evidence of sustained community transmission of the swine flu virus from person-to-person in at least two regions of the world before it raises its alert to the phase six pandemic level.

VOA: standard.2009.05.14