WHO:
Up to 2 billion people could be infected by swine flu if the current outbreak turns into a pandemic lasting two years, the World Health Organization said Thursday.
WHO flu chief Keiji Fukuda said the historical record of flu pandemics indicates one-third of the world's population gets infected in such outbreaks. Independent experts agreed that the estimate was possible but pointed out that many would not show any symptoms.
That's "if", but it does explain some of the caution, and puts "mild" flu into some perspective. As the article notes, not everyone would be ill. But with that many people affected, some would be bound to have severe illness. In any case, it's a pandmeic potential virus, and the story is just beginning.
Early data on the H1N1 (swine) flu suggest it has the "potential for efficient, rapid spread among countries," the CDC said.
And when a lot of people are sick, some will get very sick, including previously healthy people (hospital stats focus on sicker patients, and early data may be skewed).
Sufficient information on 22 hospitalized patients showed that 12, or about half, had underlying medical conditions that might have increased risk, but half did not, that is, they were previously healthy individuals, many of them young. There were 11 cases of pneumonia among the hospitalized. 8 wound up in intensive care, 4 had respiratory failure and 2 died.
More perspective from senior virologist Robert Webster:
Webster said underestimating the swine flu virus would be a huge mistake. "This H1N1 hasn't been overblown. It's a puppy, it's an infant, and it's growing," he said. "This virus has got the whole human population in the world to breed in -- it's just happened. What we have to do is to watch it, and it may become a wimp and disappear, or it may become nasty."