The World Health Organization may have inadvertently triggered a new wave of fear over the threat of a swine flu pandemic today by suggesting that up to 2 billion people could be infected if the current outbreak worsens.
"If the situation continues to evolve and the virus does become established in other countries, and we do move into a pandemic, we would expect the virus to infect many people," said WHO chief Keiji Fukuda at a press conference today. "Perhaps a third of the world's population could be infected with this virus, based on previous pandemic."
Fukuda quickly noted to reporters that he was making statement based on data from past pandemics and was not a predicting what would happen with the current swine flu outbreak.
"I do not want you to walk out of here saying that there is an estimate that 2 billion will get infected in the next year or so," he said. "Please do not interpret this as a prediction for the future."
The comment immediately ignited debate among infectious disease experts.
"I think that WHO could serve the world health better by providing a more evidence-based, sensible 'benchmark' of H1N1 infection," said Ed Hsu, associate professor of public health informatics at the University of Texas School of Health Information Sciences and School of Public Health. He argued that the 2 billion figure, based on past pandemics, does not take into account recent public health improvements. Moreover, his own research has suggested that the rate of swine flu infection in the United States may have already stabilized.
"One could reasonably question the reliability of WHO's statement of mass infection," he said. "By making such statement without strong backing WHO may risk putting its accountability on the line."
On the other side of the argument is Dr. Christian Sandrock, assistant professor of clinical medicine in the Division of Infectious Diseases at the UC Davis School of Medicine. He said the numbers cited by Fukuda are less important than the overall message, which is that we should be prepared for a second wave of swine flu later this year.
"I think this is an important discussion -- not the numbers, but the likelihood of larger spread in the second wave," he said, adding that such a discussion is crucial for vaccine development and other issues of preparedness. "Much better to do this now than later."
Still, the question of whether the public and the medical community should worry about a possible swine flu pandemic has big implications for preparing for such an event -- particularly in regard to vaccines.
As drug makers await the viral "seed strain" they need to begin manufacturing doses of swine flu vaccine by the millions, health officials are mulling what form the jabs might take -- and if Americans may be facing up to three needle jabs this fall.
The debate is not a trivial one. While infectious disease experts have said that there is much about the new strain of the H1N1 virus that they still do not know, government agencies must decide soon whether or not a swine flu vaccine will be needed -- particularly because such a vaccine would take months to develop and produce.