WHO declares swine flu a pandemic, warns moderate severity expected

衣食住行 · 发表于 2009-6-11 09:55

TORONTO - The World Health Organization declared the swine flu outbreak a pandemic Thursday, the first since the Hong Kong flu of 1968.
Director General Dr. Margaret Chan made the declaration, saying the new H1N1 virus is currently expected to lead to a pandemic of moderate severity. Her announcement in Geneva was scooped by a number of countries which earlier revealed they'd been informed of the pending move.
Chan acknowledged raising the pandemic level might create some confusion and concern, but stressed the move doesn't mean the virus is becoming more virulent. Pandemic status relates to geographic spread, not disease severity, she said.
"We are satisfied that this virus is spreading to a number of countries and it is not stoppable," Chan said of the decision to formally declare what many experts have been describing for some time.
Dr. Allison McGeer, an influenza expert at Toronto's Mount Sinai Hospital, is one of those who feels the declaration is simply an acknowledgment of reality. But she nonetheless welcomed the move.
"From a science perspective, anybody will tell you that this has been a pandemic for weeks," said McGeer, who suggested political and other concerns have mired the WHO in a declaration process that has trailed behind the science.
"You can understand why the World Health Organization is having trouble but it does put you in this really odd situation of having a zebra out there that you can't call a zebra."
As of Wednesday, 74 countries had declared 27,737 confirmed cases of swine flu and 141 deaths.
Canada, one of the hardest hit countries, has confirmed 2,978 case in all provinces and territories but Newfoundland and Labrador. The deaths of four Canadians have been linked to infection with the virus.
Ontario is the hardest hit province, with 1,562 confirmed cases. But recent spikes in Nunavut, with 96 cases, and Manitoba, with 56, have been described by the WHO as being of serious concern.
Indigenous populations were badly hit in previous pandemics and evidence of severe illness in some northern Manitoba First Nations communities has the WHO worried that the pattern may be playing out again with this virus.
The swine flu virus was first spotted in California in mid-April, in two children who had had no exposure to pigs. The U.S. Centers for Disease Control alerted the WHO, as required under the International Health Regulations. Within days, word emerged that Mexico was experiencing an alarming outbreak that looked like severe influenza.
Quick work by Mexican, Canadian and U.S. scientists pieced together that the outbreaks were caused by the same virus, which was spreading rapidly. The WHO raised the pandemic alert level to Phase 4 on April 27, and then to Phase 5 two days later.
Under the WHO's pandemic alert level, a pandemic is declared at Phase 6 when the WHO sees evidence of sustained spread in the community in countries in two different WHO regions. In recent weeks spread in the United Kingdom, Spain, Japan and Australia has at various times threatened to push the world across that threshold.
But on Thursday, Chan declined to reveal which country or countries' spread led to her decision. She said a combination of factors contributed to the call.
Those included evidence of transmission in a number of countries and acknowledgment by some unnamed countries that their surveillance systems may not be catching community spread.
As well, there are reports that the new virus may be crowding out seasonal flu strains and that groups badly hit in earlier pandemics - young healthy adults, pregnant women and aboriginal communities - may be harder hit by this virus than by seasonal flu strains.
Chan put the evidence and her intention to declare a pandemic to the experts on the WHO's emergency committee in a teleconference Thursday. None of the experts - whose names the WHO does not make public - disagreed with the decision to declare a pandemic, she said.
The WHO's unwillingness to reveal which country or region had taken the virus across the threshold was criticized by a flu expert who had earlier suggested the agency's scientific credibility was in peril because of its delay in declaring a pandemic.
"While the announcement is welcome in terms of addressing the science, the lack of transparency in terms of which country's activities factored in the decision is disappointing," said Dr. Michael Osterholm, director of the Center for Infectious Diseases Research and Policy at the University of Minnesota.
"Transparency is everything. If public health science is to have credibility in government, the private sector, and even with the general public, transparency has to be our highest priority. And this doesn't feel very transparent."
Canadian officials confirmed they had been notified of the jump to Phase 6. They planned to respond later Thursday and it was expected they would address Canada's intention to make H1N1 vaccine. The country has a long-standing contract with vaccine giant GlaxoSmithKline that ensures the first pandemic vaccine produced at the company's Ste-Foy, Que., plant will be reserved for Canadians.
While vaccine manufacturers have begun working on an H1N1 vaccine, many steps have to be taken before vaccine will be available to the public. Trial lots must be produced and tested for safety and to determine what sized dose - and how many - each person might need for protection.
The WHO has said it will likely be four to six months before the first batches of vaccine are available for use.

bigwood · 发表于 2009-6-11 10:27

{:3_106:}

vilna · 发表于 2009-6-11 11:26

{:3_106:} 世卫终于把甲型H1N1流感大流行警戒级别提升至最高的第六级提到六级------全球大流行了～～～～～

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