World at crossroads in swine flu crisis, conference told

Monday, May 18, 2009

World at crossroads in swine flu crisis, conference told

Time is GMT + 8 hours
Posted: 18-May-2009 04:29 hrs

A railway conductor (L) and a passenger wear facemasks at a station in Kobe, Hyogo prefecture, in western Japan. The swine influenza virus could fizzle out, trigger a "mild" pandemic still capable of claiming many lives or become a historic killer, a major medical conference was told on Sunday.

The swine influenza virus could fizzle out, trigger a "mild" pandemic still capable of claiming many lives or become a historic killer, a major medical conference was told on Sunday.

Renowned European virologist Albert Osterhaus urged watchdogs to keep up their guard, even if the new strain of H1N1 virus had turned out to be less worrisome than thought a few weeks ago.

"The current H1N1 threat is serious," Osterhaus said in a briefing to European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) in Helsinki, the first major medical forum to be held since the crisis erupted on April 24.

"The virus has three options," said Osterhaus, a professor of the Erasmus Medical Centre at the University of Rotterdam in the Netherlands.
"First, it could disappear spontaneously, but I'm not convinced that this will be the case.

"It could also cause a mild pandemic, like Asian flu," he said, referring to a 1957-8 outbreak that killed between one million and four million people.

By comparison, normal -- so-called seasonal -- flu kills between a quarter to half a million people each year, according to the World Health Organisation (WHO).

"In a doom(sday) scenario, we could have a severe pandemic, similar to the Spanish flu, and that could arise out of a mutation of the virus," Osterhaus said, referring to the 1918-19 pandemic believed to have killed some 50 million people.

He cautioned about the grimmest ideas: "I'm not predicting that any of these things is going to happen but even if there's only a 10 percent chance that you would have of a scenario like that, we had better be prepared."

Drawing on the latest data, Osterhaus and fellow expert Javier Garau, a professor at Spain's University of Barcelona, provided this snapshot of the virus and the combat against it:

-- INFECTIOUSNESS:
From May 3 to May 17, the number of worldwide cases rose from 900 to more than 8,000, spreading to countries in Europe and Asia.

H1N1 may be slightly more infectious than a seasonal virus. On average, every infected individual goes on to infect 1.4 to 1.6 other people.

A high proportion of cases are occurring among young people, which suggests older people may have some immunity from past exposure to a similar virus, said Garau.

People can be contagious a day prior to the onset of disease and up to seven days afterwards.

-- VIRULENCE:
The new flu is roughly on a par with seasonal flu in terms of its death toll.
It shows none of the genetic markers of highly lethal pathogens such as Asia's H5N1 "bird flu" virus. The worry, though, is that this could happen if the microbe swaps genes with other viruses.

Cases show classic symptoms "of a mild influenza," with sore throat, fever and headache, although there is also a high percentage with nausea and gastro-intestinal upset, said Garau.

-- TREATMENT:
The new virus responds to the oseltamivir, the frontline antiviral drug called Tamiflu, which has been stockpiled as a result of the bird flu scare.

A concern is that the new virus may pick up genes from seasonal flu viruses that in the past two seasons have shown signs of resistance to the drug.

-- VACCINE:
A vaccine can be produced against the current strain H1N1, but could be powerless if the virus makes a big genetic leap.

In addition, roughly six months will be needed before the first dose emerges from vaccine plants and a shortage of manufacturing capacity means maybe only a billion of the world's 6.7 billion people could be innoculated initially, said Osterhaus.

These problems pose a dilemma, for vaccine strategists will shortly have to decide which is the greater threat: is it seasonal flu virus? Or is it swine flu virus, which could in any case fade away or shift into a different target?

"It is a very difficult decision to take," said Osterhaus, who argued for "a flexible approach" capable at least of aiming at both threats.

The annual four-day ECCMID conference winds up on Tuesday. — AFP

From TODAY, 18-May-2009; see the source article here.