As of 27 April 2009, the United States Government has reported 40 laboratory confirmed human cases of swine influenza 'A' type H1N1 with no deaths, Mexico has 26 confirmed human cases with 7 deaths, Canada has reported 6 cases with no deaths, the UK 2 cases with no deaths and Spain 1 case with no deaths.

The World Health Organisation (WHO) has raised the level of influenza pandemic alert from the current Phase 3 to Phase 4 based upon epidemiological data demonstrating human-to-human transmission and the ability of the virus to cause community-level outbreaks.  The infection route is person-to-person droplet and the spread of the infection from Mexico was inevitable, although the mortality rate suggested from the Mexico epidemic has not been replicated in cases seen in North America and Europe, which is reassuring.  The number of presenting cases in Mexico has also reduced in the past few days.

Current evidence suggests a much greater prevalence of the illness in Mexico than was originally reported, with the mortality rate not being as dramatic as reported in the media. Additionally the virus has some significant similarities to seasonal flu for which many of us have "cross immunity".  The change to a higher phase of pandemic alert indicates that the likelihood of a pandemic has increased, but not that a pandemic is inevitable.  As further information becomes available, WHO may decide to either revert to phase 3 or raise the level of alert to another phase.

Given the widespread presence of the virus, the WHO consider that containment of the outbreak is not feasible.  The current focus should be on mitigation measures.  Although the Foreign & Commonwealth Officer are advising against all but essential travel to Mexico, the WHO have recommended not to close borders and not to restrict international travel. 

To read more - click here