WHO raises pandemic threat level... again

M-O-O-N, that spells Phase 5:

The World Health Organization on Wednesday raised its global pandemic alert level to five — its second highest level — meaning a pandemic is imminent and countries must finalize preparations to deal with the outbreak of swine flu.

"Based on assessments of all available information and following several expert consultations, I have decided to raise the current level of influenza pandemic alert from Phase 4 to Phase 5," WHO director general Margaret Chan said during a briefing from the organization's headquarters in Geneva.

Phase 5 is called when there is human-to-human spread of a virus in at least two countries in one region, according to WHO's pandemic response guidelines.

Chan said the new alert level is a signal for governments around the world to take action with "increased urgency and at an accelerated pace."

Meanwhile, the idea that two different strains are involved has been raised again:

A leading West Australian virologist says it is possible the Mexican outbreak of swine flu could be a different strain to the virus detected in the United States.

More than 150 people in Mexico have died from the virus while there have been no fatalities in the US.

Dr David Smith from Pathwest says there could be a number of reasons for this, but it is an unusual situation.

"We are seeing two very different descriptions of disease with apparently more severe disease occurring in Mexico," he said.

"And then the cases as have occurred outside of Mexico have been quite mild infections people have recovered from. It is unusual to see that much difference in the patterns of disease by what appear to be very similar viruses.

"If we don't know exactly what the strain is and how it compares genetically to the one that's coming from the US," he said.

"It's something we need to know if that is the case or not, but that may not necessarily be the case, the apparent differences may be explained by other reasons."

Dr Smith says it is likely both countries have the same strain but researchers will need to wait for the results of genetic testing to be sure.

From the ABC. Let's hope it's not two different strains, and that the other explanations given in the Slate article cited in my previous post are the reason. Because if it is two strains, it would be only a matter of time before the more virulent one hops Mexico's borders. On the other hand, it's also possible that infection with the mild strain will confer immunity to the virulent one.

Meanwhile, though, they're backtracking on the number of reported deaths; they're now saying only seven deaths in Mexico and one in the US can be definitely linked to this outbreak. So maybe this isn't as big a deal as previously thought. No doubt we'll know soon enough.