How long until WHO declares alert level 5?
On 27 April 2009, the World Health Organisation raised the level of influenza pandemic alert from the phase 3 to phase 4.
There are 6 phases in the alert system. Phase 1 means there is no threat, while Phase 6 means a pandemic is in progress.
Phase 4 is characterized by verified human-to-human transmission of an animal or human-animal influenza reassortant virus able to cause “community-level outbreaks.” Phase 4 indicates a significant increase in risk of a pandemic but does not necessarily mean that a pandemic is a forgone conclusion.
Phase 5 is characterized by human-to-human spread of the virus into at least two countries in one WHO region. The declaration of Phase 5 is a strong signal that a pandemic is imminent.
In Scotland, it is known that a couple returning from honeymoon in Mexico are the UK’s first victims of Swine Flu. They were in the UK for 5 days before showing any symptoms of infection, and have been in contact with at least 20 other people in that time. One of their parents has now shown symptons and is awaiting test results to confirm or exclude H1N1 infection.
With the virus having an incubation period of upto 7 days, the WHO may be forced to upgrade the alert level to 5 by the end of this week.
